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The Multiple Mysteries of Multiple Stars: OΣ 298 and KZA 105

There are double stars, and there are triple stars, and there are multiple stars . . . . . . . and then there are multiple stars.

Odd multiple stars . . . . . . . with attributes you would never think of attributing to multiple stars . . . . . . . with characteristics that are very uncharacteristic of multiple stars . . . . . . with odd quirks you would never in your wildest imagination imagine to be possible of multiple stars.

But that’s really all I can reveal in the first few paragraphs of this cryptic discussion.  Because in order to lure you further into the labyrinthine depths lurking beyond the bottom edge of this paragraph, I have to put a halt to the hints – except to say you’re in for a pair of uniquely unique surprises.

So if I’ve awakened your curiosity, and (or) if you’re harboring a stellar craving for adventure, follow me into the dark photonic wilderness . . . . . . . . . . . . . . .

Actually, we’ve been in this area before, but with a discretely zealous measure of zeal I left our intriguing targets unlabeled:

We’re returning to Nu-1 and Nu-2 (ν1 and ν2) in Boötes, so follow the line that runs northeast from Delta (δ) Boötis through Mu (μ) Boötis (Alkalurops) to ν1, ν2. (Stellarium screen image with labels added, click to enlarge).

We’re returning to Nu-1 and Nu-2 (ν1 and ν2) in Boötes, so follow the line that runs northeast from Delta (δ) Boötis through Mu (μ) Boötis (Alkalurops) to ν1, ν2. (Stellarium screen image with labels added, click to enlarge).

From Nu-1 and Nu-2 (ν1 and ν2), slide southeast one degree to 5.25 magnitude Phi (φ) Bootis, a pleasing yellowish G8 sun.  From there, reverse your direction ninety degrees to the southwest and drop less than half a degree to our goal, seventh magnitude OΣ 298 (STT 298).  (Stellarium screen image with labels added, click for a larger view).

From Nu-1 and Nu-2 (ν1 and ν2), slide southeast one degree to 5.25 magnitude Phi (φ) Bootis, a pleasing yellowish G8 sun. From there, reverse your direction ninety degrees to the southwest and drop less than half a degree to our goal, seventh magnitude OΣ 298 (STT 298). (Stellarium screen image with labels added, click for a larger view).

OΣ 298  (STT 298)              HIP: 76382   SAO: 64800
RA: 15h 36.0m   Dec: +39° 48’
.             Magnitudes        Separation        Position Angle         WDS
AB:         7.16,   8.44              1.167”                 181.8°                 2013
AB,C:     6.90,   7.75            121.50”                 328.0°                 2012
AB, D:    6.90, 13.94            167.40”                 224.0°                 2002
AB,E:     6.90, 12.07            456.00”                 335.0°                 1999
Distance: 71 Light Years
Hussey Orbital DiagramSpectral Classifications: “A” is K4, “B” is K5, “C” is K0
Notes:   
AB is a gravitationally attached pair, orbital data is available here.  (You can see an early attempt at determining an orbit by clicking on the thumbnail at the right).
AB is also LDS 798; AB,C is also HJL 225 and SHY 77
AB,C is physical
AB,D   ———   not yet!  We’ll get there, though . . . . . honest.  😉

OK, where to start . . . . . .

Let’s begin with the AB pair, which I should have tried to split, but overlooked completely because I was eager to get on to the three more distant members of this family of five.  With a separation of 1.167”, I should have been able to get it with the 9.25 inch SCT I was using that night.  In fact, it should be split-able with a six inch and probably a five inch refractor, the limiting factor being the 1.28 difference in magnitudes of the two stars.  But as I said, I was overcome with an irrational desire to meet the other members of this stellar troupe.

To be truthful, there was one member in particular I was searching for . . . . . . . ah, but I’m getting ahead of myself once again.  Pardon my lack of restraint.

Let’s stay with alphabetical order and proceed to AB,C, which isn’t difficult at all to find since it’s less than a magnitude fainter than the welded-together AB pair.  The orange tints of AB and AB,C (attributable to their spectral classifications of K4 and K5) are really worth pursuing on their own account since they add a decoratively tasteful touch to the sparse dark field in the eyepiece:

 East & west reversed to match the refractor view, click to enlarge the image.

East & west reversed to match the refractor view, click to enlarge the image.

Although Johann Heinrich von Mädler uncovered the AB pair in 1843, it was Otto Struve’s initials (the Greek letters OΣ) which were attached to it, possibly because Herr Otto added the 7.75 magnitude “C” component in 1867.  And if you look at the sketch, you’ll see that a line drawn from AB to “C” and extended toward the northwest edge of the field will also lead you to twelfth magnitude “E,” which was added in 1934 by G.V. Simonov, apparently while working at the Berlin Babelsberg Observatory.

And that – finally – leads us to where we’ve been headed since the first words of this piece: the mysterious and enigmatic “D”.

The 13.94 magnitudes of light listed in the Washington Double Star Catalog (WDS) for “D” is fainter than what it actually is, a fact I’m rather sure of for two reasons:  first, I had no problem seeing it in the 9.25 inch SCT, and second, I had no problem in discovering it’s true nature, which can be seen below in the inset I’ve added to the sketch of OΣ 298:

 A healthy application of averted vision was necessary to detect a definite “un-star-like” quality about the odd object in the inset.  (East & west reversed once again, click for a much better view of the inset).

A healthy application of averted vision was necessary to detect a definite “un-star-like” quality about the odd object in the inset. (East & west reversed once again, click for a much better view of the inset).

 Burnahm on STT 298As you can see in the inset at the bottom right of the sketch, there’s something rather fuzzy about that “D” component . . . . . which was also noted by S.W. Burnham in 1901 (click on the thumbnail attachment at the left).  In fact, if you read S.W.’s entry (the one in the yellow box) you’ll see this odd comment: “h 1930 is in the field; small, round, and not well defined for measurement.”  But S. W. Burnham being S.W. Burnham, he of course couldn’t resist measuring it.

 So now, what in the wonderfully weird world of multiple stars does “h 1930” refer to? Well, if you’re familiar with double star nomenclature, you would expect it to refer to number 1930 in Sir John Herschel’s Fourth Double Star Catalog of 1830-1831 (jump to p. 331 if Sir John’s essay doesn’t come up; his entry for h 1930 is near the top of page 378) – but that star happens to be way up north in Cassiopeia, where it’s twinkling under its current WDS designation, HJ 1930 – and if you recall, we’re still in Boötes.

J Herschel obsv of NGC 5966-h 1930Sir John also contributed a large catalog of deep sky objects (scroll two-thirds of the way down) which just happens to contain another object designated “h 1930”.  He described it this way: Faint, Small, gradually brighter in the middle (“F; S; R; g b M;”).  If you click on the thumbnail at the right, you’ll see his entry at the bottom of the page.   And if you look closely, you’ll see another number assigned to this object in the second column, the one labeled “Synonym,” which reads “III. 634”.  And darned if that doesn’t look like something  Sir John’s father, Sir William Herschel (who was fond of using Roman numerals in his double star designations), would use as a catalog number.

Wm. Herschel on III 634 aka NGC 5966As it turns out, Sir William was also a restless seeker of objects other than double stars, and “III. 634” is actually a catalog number from his second large catalog of deep sky objects (scroll to fifth title from the bottom).  You can see his observation by clicking on the thumbnail image at the left, where it’s described as very faint, very small (“vF. vS.”).  And, in fact, “III. 634” is now known by its number in the New General Catalog, NGC 5966.

Which is because it’s not a star – it’s a . . . . . . . galaxy.

STScI photo of OΣ 298 with labels added, east & west reversed to match the sketches.  Click on the photo for a larger view.

STScI photo of OΣ 298 with labels added, east & west reversed to match the refractor image. Click on the photo for a larger view.

To be more precise, NGC 5966, aka OΣ 298-D, is an elliptical galaxy, and may even be a quasar, although opinion on that is somewhat uncertain.  Quasars (short for quasi-stellar radio object) were first discovered in 1963, and are highly energetic sources of radio waves and visible light which are peculiarly out of proportion to their physical size.  According to the NGC/IC Project web site, the visual magnitude of NGC 5966 is 12.7, its surface brightness (a better measure of its visual brightness) is 13.4, and it measures 1.8’ x 1.2’ in size, all of which explains why I had little problem detecting its smudged appearance in the 9.25 inch SCT.   I have no idea what prompted the 13.94 magnitude listed for “D” in the WDS, but it’s clearly easier to see than that magnitude would lead one to believe.

M.G. Bigourdan on STT 298So how did a galaxy end up being cataloged as a member of a multiple star family?  Good question – and the only light I can shed on the topic is that this particular member of the group was added in 1886 by Guillaume Bigourdan, a French astronomer working out of the Paris Observatory.  Most likely he was using the great thirty-three inch Meudon Refractor, and if so, it’s surprising that he failed to realize this object wasn’t a star.  His observation can be seen by clicking on the thumbnail illustration at the right – the object now labeled as “D” is referred to in Bigourdan’s data as “AB/2 C”.  (The separation he lists matches Burnham’s information, but the position angle is off about 90 degrees, presumably an error that Burnham seems to have recognized, possibly because it was also made on one of the entries for AB).

In the meantime, as I was writing this, I was overcome with an unquenchable urge to return to OΣ 298 and see if I could break the weld on the AB pair.  And surprisingly, it was less difficult than I expected.  I suspect if I had been paying more attention to it on the night I made the first pair of sketches I would have detected a split in the two stars . . . . . . . because when I returned, I could clearly see each of them at 175x in a 14mm Radian.  The seeing was very jittery at the time, so I carefully worked my way up through 204x (a 12mm Radian) and 245x (a 10mm Radian).  I found myself encouraged enough by the 245x view to risk leaping into a magnified abyss with my trusty 7.5mm Celestron Halloween Plössl.  It very generously served up an eye-pleasing 327 diameters of shivering white light, as well as a splendid view of OΣ 298-D, aka h 1930, aka H III. 634, aka NGC 5966:

Notice the weak orange glow of the AB pair has surrendered to a weak shade of white under the increased magnification!  (East & west reversed again, click for a larger and better view).

Notice the pale orange glow of the AB pair has surrendered to a weak shade of white under the increased magnification! (East & west reversed again, click for a larger and better view).

So – an amazing multiple star with a galaxy as one of its members!

What could be stranger than that, you ask?

Well take a look at the upper right area of the eyepiece field of view in one of the first two sketches above (or take a peek here), and you’ll see a faint scattering of stars hanging on for dear life as they stretch from the north the edge of the field to the south edge.  That scattering of stars just happens to go by the collective name of KZA 105, and has a total of (ready for this?) . . . . . . . . nine members!

 KZA 105 data

.

One of the peculiarities that emerges quickly when you look closely at the table of data above is the individual members of this group of stars are assigned letters based on their increasing distance from the primary, which can also be seen in the labeled sketch below, although it’s not quite as obvious there:

 (East & west reversed to match the refractor view, click for a larger view).

East & west reversed to match the refractor view, click for a larger view.

And here’s the same sketch without the clutter caused by the labels:

The two bright stars down in the southwest corner are the AB and AB,C members of  OΣ 298.  East & west reversed again, click to enlarge.

The two bright stars down in the southwest corner are the AB and AB,C members of OΣ 298. East & west reversed again, click to enlarge.

Another peculiarity is that most of the measurements above were first made in 1982 (AI was added in 1984) with the exception of DF and HI, which were first measured in 1893 – and they just happen to also be the brightest members of the group.  My usual source for measurements from that period, S. W. Burnham’s A General Catalogue of Double Stars within 121° of the North Pole was no help, nor were other sources for that era.

In fact, tracking down information on KZA 105 resulted in several futile hours of research as there is virtually no information about this system available on line.  I did discover the initials KZA refer to S. M. Kazeza, who served as a member of the team that put the Hipparcos catalog together.  And, I found one article written by him which was published in 1984 in volume nine of the Bulletin of the Astronomical Observatoire Royale de Belgique, which is currently unavailable on line.

When you see this many stars listed as components in a system, and especially with such wide separations, it’s usually because they have similar proper motions.  Fortunately, the WDS provides the proper motion of all of the members of this group, which I included above (the numbers represent seconds of arc per thousand years, so inserting a decimal point at the beginning of each number will tell you how much each star moves in a single year).

The column labeled “First” refers to the first of a pair of stars, and the next column refers to the second of the pair.  In other words, in the case of the AB pair, the proper motion of “A” is -027 in RA and +001 in Dec, while “B” is -011 in RA and +002 in Dec.  A plus sign in front of a number indicates eastward motion in RA and northerly motion in declination; a negative sign means westward motion in RA and southerly in declination.

The table indicates a general slight motion to the west in RA and south in Dec for most of the individual stars (scan the numbers in the “Second” column).  “A” (in the “First” column) is a notable exception, moving due west at a considerably faster rate than the other members (-027 +001), “I” stands out because of its northwesterly motion (-023 +015), and “G” looks like it isn’t going anywhere at all (+000 -001).

So with the exception of “A”, “I”, and “G”, you could say there’s a general shared similarity in motion between this collection of stars.  That may partially explain why these nine stars were grouped together, but I suspect there’s more to this mystery lurking somewhere out there in the galactic darkness.

One thing, though, should be obvious from all of the above:  multiple stars can be mysterious beyond words – and they’re certainly not boring!

And before I forget about it, my thanks once again to Brian Mason at the U.S. Naval Observatory (home of the Washington Double Star Catalog) for providing me with data on both OΣ 298 and KZA 105.

Next time out we’ll take an old-fashioned star-hopping tour through the realm of the Nu twins in Corona Borealis.

Until then, Clear Skies!  😎

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A Pair of Nu Ones: Nu-1 and Nu-2 in Boötes and Corona Borealis

.                                                   There I was,
                             looking for something new
.                                                            to do,
.                                              when I ran into
.                                              Nu-1 and Nu-2.

                         And not just once, but twice!

But I suppose I should explain before the guys in the white coats get here  . . . . . . .

It was one of those cursed dark and stormy nights – again.  In fact, it was like November in May: rain pounding on the roof so hard it almost echoed inside the house; over-sized drops of water throwing themselves madly at the wooden planks of my deck, spreading out on impact like the shock waves of a supernova; and water rushing down the streets in torrents that threatened to turn into rivers wide enough to float barges of grain.  And above it all, a constant howling wind that somehow had broken the shackles of its winter chains and escaped into late spring.

So longing for a calm, clear, dark, and storm-less night, I picked up my well-worn copy of Sky & Telescope’s Pocket Atlas and began looking for future telescopic targets.  I was searching for new horizons, sights to stir the soul, un-tracked trails in the vault of wilderness beyond the storm clouds – in fact, anything to turn my thoughts away from the relentless rain.  And fortunately for my water-soaked sanity, I quickly found what I needed.

There it was, on chart number fifty-two, parked a few degrees west of the Hercules keystone — barely beyond the Herculean border in fact — arrayed one above the other in Corona Borealis: Nu-1 and Nu-2.  Or as Hipparchus might have referred to them if he had been peering over my shoulder at the atlas, ν1 and ν2 .

As my eyes roamed over the surrounding stellar terrain, they were drawn to another pair of Nu’s.  These were also barely beyond the Herculean border, this time in Boötes, unlikely as that may seem.  In fact, they’re wedged into an angle formed by the western edge of Hercules and the northern corner of Corona Borealis, parked on a shelf as it were.  And unlike the prior pair, they’re arrayed side by side – or at least they are on the chart (number fifty-three if you’re following along).

I breathed a loooooong sigh of relief, launched myself into a frenzy of stellar research, and ignored the rain as it ran riot outside my windows.

Now one of the more admirable traits shared by the two pairs of Nu twins is you can soak up the splendor of their photonic beauty with a mere fifty millimeters of aperture.  In fact, they even qualify as outstanding and easily separated binocular binaries.  But if you have more aperture, by all means bring it along – it’ll come in very handy before we’re finished.

 Pay close attention now -- there are two Nu-1's and Nu-2's (ν-1 and ν-2) on this chart!   You'll find the Boötes pair is located above and to the right of the center of the chart, or about five degrees east (left) of Beta (β) Boötis.   But we’re going to start instead with the Corona Borealis Nu's.  To get there, fix your eyes on Epsilon (ε) and Zeta (ζ) Herculis, located at the southeastern and southwestern corners of the Herculean keystone.  Extend the line that runs from Epsilon (ε) to Zeta (ζ) another four degrees to the west (there's actually a 6.4 magnitude star there) and you'll find yourself parked halfway between Xi (ξ) Coronae Borealis, located 1.5 degrees to the south, and Nu-1 (ν-1) and Nu-2 (ν-2), which are 1.5 degrees to the north.  And now let's get to work!   (Stellarium screen image with labels added, click for a larger view).

Pay close attention now — there are two Nu-1’s and Nu-2’s (ν1 and ν2) on this chart! You’ll find the Boötes pair is located above and to the right of the center of the chart, or about five degrees east (left) of Beta (β) Boötis. But we’re going to start instead with the Corona Borealis Nu’s. To get there, fix your eyes on Epsilon (ε) and Zeta (ζ) Herculis, located respectively at the southeastern and southwestern corners of the Herculean keystone. Extend the line that runs from Epsilon (ε) to Zeta (ζ) another four degrees to the west (there’s actually a 6.4 magnitude star there) and you’ll find yourself parked halfway between Xi (ξ) Coronae Borealis, located 1.5 degrees to the south, and Nu-1 (ν-1) and Nu-2 (ν-2), which are 1.5 degrees to the north.  And now let’s get to work! (Stellarium screen image with borders and labels added, click for a larger view).

Now this may seem complicated, but it’s not really.  First I’ll list the basic data for Nu-1 and Nu-2 separately, and then I’ll add the table with separations and position angles of the individual components:

Nu-1 (ν1 )  (20 Coronae Borealis) (Σ I 29, or STFA 29)      HIP: 80197   SAO: 65257
RA: 16h 22.4m   Dec: +33° 48’
Distance: 556 Light Years
Spectral Classification: M2

Nu-2 (ν2 )  (21 Coronae Borealis)     HIP: 80214   SAO: 65259
RA: 16h 22.5m  Dec: +33° 42’
Distance: 545 Light Years
Spectral Classification: K5

In the data below, Nu-1 is the “A” component, Nu-2 the “B” component
Designation          Magnitudes     Separation      Position Angle      WDS
AB (STFA 29)          5.39,   5.58          365.60”                 164°               2011
AC (HN 81)              5.39, 11.30           68.10”                  241°              2002
AD (STFA 29)          5.39, 12.90          277.10”                  153°               2002
BE (H VI 18)            5.58, 10.20          100.00”                   16°                2002

NOTE (July 2014): See update on WDS identifications, which is further down the page (just prior to the Boötes discussion).

If you’re using a 50mm or 60mm scope, or binoculars, you’ll find your attention is drawn immediately to the “A” and “B” components, Nu-1 and Nu-2.  If you’ve got more aperture, probably at least one hundred millimeters worth, you’ll be able to pry loose the “C” and “E” components.  “D” is another story entirely, which we’ll get to later.

To get started, here’s the view through my 50mm Zeiss refractor:

Even in a fifty millimeter lens, the orange hues of “A” and “B” are hard to miss.  And there are plenty of background stars, even at this aperture, to hold your interest.  (East & west reversed to match the refractor view, click for a larger version).

Even in a fifty millimeter lens, the orange hues of “A” and “B” are hard to miss. And there are plenty of background stars, even at this aperture, to hold your interest. To get the full effect of the color, click on the sketch to enlarge it. (East & west reversed to match the refractor view).

The primary and secondary, Nu-1 and Nu-2, are aligned pretty close to a north-south axis.  Nu-1 is the northernmost of the pair and is positioned slightly to the west of the more southern Nu-2 — and Nu-1 has staked out a claim on most of the companions.  In order to extricate them from the darkness, though, you need a bit more than a 50mm refractor.  I used a 9.25 inch SCT to view them, but as I mentioned earlier, you should be able to catch the AC and BE pairings with a minimum of a hundred millimeters.

Here’s the mesmerizing view I found in the SCT on the night after the sketch above was made:

This sketch was made much earlier in the evening than the previous one, so west is rotated further down to the left in this scene. The colors are absolutely un-missable when you put more light gathering power to work. (East & west reversed once again, click for a larger view).

This sketch was made much earlier in the evening than the previous one, so west is rotated further down to the left in this scene. The colors are absolutely un-missable when you put more light gathering power to work. (East & west reversed once again, click for a larger view).

Once again, Nu-1 is on the north side of the sketch, and just below it and slightly south of west you can see the 11.30 magnitude “C” companion.   The 10.20 magnitude “E” component, which is linked to Nu-2 (the “B” partner in this pair), is visible above it in the sketch, or just slightly east of north.

So where did “D” go?  At a distance of 277.10” from Nu-1 (“A”), even at a magnitude of 12.9 it should be visible in a 9.25 inch SCT.

After pinning down the “C” and “E” companions on my first visit to the Nu twins, I did some mental comparing of the separation between Nu-1 and Nu-2 (AB = 365.60”), Nu-1 and “D” (AD = 277.10”), and Nu-2 and “E” (BE = 100.00″), and quickly came to the conclusion that “D” was actually at about the same distance from Nu-1 as the “E” companion is.  Again, with a bit of mental magic, I could also see the position angles of AD (153°) and BE (16°) almost overlap at the respective distances of AD and BE.

And sure enough, when I turned to Vizier to diagram them, that’s what I found:

"D" should be where the arrow terminates in the green square at the edge of "E".  (East and west reversed to match the refractor view, click for a larger version).

“D” should be where the arrow terminates in the green square at the edge of “E”. (East and west reversed to match the refractor view, click for a larger version).

In fact, it looks as if “D” and “E” are virtually occupying the same position.  (For a tutorial on how to use the software in Vizier to plot position angles and separations, see this article in the April 2013 issue of JDSO).

I enlarged a photo of the area, which is basically the positive image of the negative one used for the Vizier plot, and came up with this result:

STScI photo flipped to match the refractor image.   For a better view of "D", click to enlarge.

STScI photo flipped to match the refractor image. For a better view of “D”, click to enlarge.

The arrow I inserted is pointing at what might be “D” – but it could also simply be an artifact of the photographic process.

Brian Mason at the US Naval Observatory (the same folks who bring us the indispensable Washington Double Star Catalog), was kind enough to supply me with the observational data for all of the components of Nu-1 and Nu-2.   There are five observations of AD recorded in the WDS data, ranging from 1913 to 2002, which show little variation.  The separation runs from 281.73″ in 1913 to 277.11″ in 2002, and the position angle from 154.3 degrees in 1913 to 153.3 degrees in 2002.   “E” shows very little motion as well — the first observation listed for it in the WDS (1879) shows a separation of 104.56″ with a PA of 15.6 degrees, again not much different than the most recent 2002 observations of 100.01″ and 15.9 degrees.

Click to enlarge!

Click to enlarge!

At this point, I turned up some very interesting details.  The 1879 observation of the BE pair was made by S.W. Burnham, and from what I can determine, he was using his six inch Clark refractor, which would seem to explain his not detecting the “D” component.  The initial 1913 observation of “D” was made by William Doberck, and after one heck of a lot of research, I discovered he was also using a six inch refractor based in his observatory in Sutton, England.  If you click on the thumbnail at the right, you’ll see four observations recorded for the AD pair, which is labeled there as BC.  Those four observations were averaged to yield the result shown in the last two columns at the right (in the red box), which match the data listed in the WDS.  And if you look closely, you’ll see the four observations were made at a magnification of 150x. (!)

Note that there is no magnitude listed there for any of the stars.   If it wasn’t for the fact that the WDS lists separate magnitudes for the “D” and “E” components, I would be tempted to say both designations are referring to the same star.  At any rate, based on the accumulated store of data, it certainly appears that “D” is really there, buried in the glare of the 10.2 magnitude “E” component.

Before we move on to Boötes, if you look at the data above for the Nu twins you’ll see two of Sir William Herschel’s catalog numbers listed under the designation column.  He discovered H VI 18, the BE pair, on July 30th, 1780, and described “B” as “red” and “E” as “garnet.”   (p. 152 of 1782 Catalog in Philosophical Transactions, Vol. 72, 1782).  In the case of the AC pair, which he designated as H N 81, he made a total of three visits: May 28th, 1791; March 20th, 1795; and March 22nd, 1795 (page 22 of the 1821 catalog, no longer available on line).

====================================================

Update: As of July, 2014, the BE listing in the WDS has been changed to BD and the “E” designation has been dropped — in other words, there are four stars in the Nu CrB system, not five.  It turns out “D” and “E” actually referred to the same star.  The key to discovering that was the realization Doberck had reversed the designations for Nu CrB “A” and “B” — his “B is the WDS “A”, and his A” is the WDS “B” . . . . . . . . which meant his BC is the WDS AD . . . . . . . . . and his AC should have been labeled BD in the WDS instead of BE.  If that sounds confusing, it’s because it is.  Steve Smith and I have combined to write a paper for the JDSO (Journal of Double Star Observers), which can be found at this link.  At any rate, here’s the updated data for Nu Coronae Borealis as of July, 2014:

Designation          Magnitudes     Separation      Position Angle        WDS
AB (STFA 29)          5.39,  5.58           354.70”                 164°                2011
AC (HN 81)             5.39, 12.62            68.10”                  241°               2002
AD (STFA 29)          5.39, 11.53           277.10”                 153°               2002
BD (H VI 18)            5.58, 11.53           100.00”                  16°                2002

====================================================

OK — let’s leap over to Boötes now and see what’s Nu.  If you look at the chart above (you can open it in a separate window here), you’ll find Nu-1 and Nu-2 Boö sitting at the northeast tip of a line drawn from Delta Boötes through Mu Boötis (Alkalurops) and extended another four degrees beyond.

Nu-1 (52 Boötis)              HIP: 75973   SAO: 45580
RA: 15h 30.9m   Dec: +40° 51’
Distance: 872 Light Years
Spectral Classification: K5

Nu-2 (53 Boötis)              HIP: 76041   SAO: 45590
RA: 15h 31.8m   Dec: +40° 54’
Designation         Magnitudes      Separation      Position Angle      WDS
AB (A 1634)           5.80,   5.80             0.05”                   32°                 2010
AB, C (Bu 1450)   5.10, 13.00           93.50”                   88°                 2002
AB, D (KZA 97)     5.10, 13.00         119.90”                 319°                 2002
Distance: 430 Light Years
Spectral Classification: A5

And the first thing to notice here is Nu-1 and Nu-2 are not cataloged as a related pair, which is not surprising considering they’re 442 light years apart!  Nevertheless, they make an enticing pair of stars for binoculars or a 50mm refractor:

And the second thing that should jump out at you from the data above is the offspring of the Nu-2 family are just a bit on the difficult side to catch sight of.  We’ll skip the AB pair (you would need equipment none of us have to split it), and instead focus our attention on the two thirteenth magnitude companions, “C” and “D.”

Let’s first take a look at Nu-1 and Nu-2 in a 50mm scope:

Nu-1 Boö one is left of center and Nu-2 Boö is right of center in this sketch.  (East & west reversed once again to match the refractor view, click to enlarge).

Nu-1 Boö one is left of center and Nu-2 Boö is right of center in this sketch. (East & west reversed once again to match the refractor view, click for a much better view).

You need a moonless sky to see the orange-ish K5 tint of Nu-1 in a fifty millimeter lens, but if you compare it closely with Nu-2, you’ll see the difference.  I was even able to detect the color differences in my Canon 10×30 IS binoculars with careful scrutiny (while I was lying flat on my back on my deck!).

If you recall our earlier fifty millimeter view of the Nu twins in Corona Borealis (easy to do – just click here), you’ll see the Boötes pair are a bit further apart.  To be more precise, the pair in Corona Borealis is separated by a distance of six arc minutes, while the Boötis duo has almost eleven arc minutes of intervening interstellar space wedged between them.  Of course, that eleven minutes of arc is actually the 442 light years of separation referred to a few paragraphs above, which is perfectly undetectable even to our telescopically aided but three-dimensionally challenged eye.

We’ll switch over to Nu-2 now, aka 53 Boötis, and see what we can see of the two thirteenth magnitude companions arrayed to the east and northwest of the primary.  But for this, you’re going to need six inches of unobstructed aperture.  It might be possible to glimpse the faint photons of “C” and “D” in a five inch refractor, but you’ll need dark skies devoid of the oceanic moisture I battle with on most nights . . . . . . .

. . . . . . . which is exactly the problem I faced when I attempted to dig those two stars out of the glare and scowl of the 5.80 magnitude AB alliance.  With persistence and penetrating visual perspicuity, though, I got ‘em – but to give you an idea of their difficulty, let’s first look at a sketch without the gray-white glow and glare:

No problem at all when the glare is gone!  “C” and “D” would have been this easy if I could have removed that radial veil. (Click for larger view, east & west reversed to match the refractor view).

No problem at all when the glare is gone! “C” and “D” would have been this easy if I could have removed that radial veil. (Click for larger view, east & west reversed to match the refractor view).

But enough of pretending and wishing for what isn’t likely.  Here’s reality:

Since averted vision isn’t much help when looking at an image on a computer screen, you’ll probably have to enlarge the image by clicking on it to see “C” and “D”. The faint star to the south of the primary isn’t cataloged as a companion. (East and west reversed once again).

Since averted vision isn’t much help when looking at an image on a computer screen, you’ll probably have to enlarge the image by clicking on it to see “C” and “D” (and even then “C” is rather hard to see). The faint star to the south of the primary isn’t cataloged as a companion.  Nu-1 is beaming in radiant orange down in the western corner of the view.  (East and west reversed once again).

And that’s just about the most realistic portrayal I’ve ever managed to coax out of a computer program!  It was every bit as hard as all that to catch sight of those two thirteenth magnitude wisps of light  —  it was averted vision all the way down.  The “C” companion was noticeably more difficult to extract from the primarial glow, which is quite consistent with its being twenty-six seconds of arc closer than “D.”   The unrelated thirteenth magnitude star to the south of the primary, which was an unexpected bonus, was about midway between “C” and “D” in difficulty.

So there you have it – two Nu pairs of stars to grace the lens of a small aperture telescope that also offer additional opportunities for those less aperture-challenged.  But there’s more to be had in the vicinity of both of these pairs of stars, so we’ll hang around in both Boötis and Corona Borealis a bit longer.  I’ve got a few more tours planned, so don’t wander away . . . . . . .

. . . . . . and Clear Skies!  😎

My 80mm Mizar Shows Me a New Way to Look at Xi (ξ) Boötis

Click on this or any of the other photos for larger views.

Several years ago I was skimming along through Cloudy Nights’ Classic Refractor Forum and I came across a discussion about an old 80mm Mizar refractor someone had purchased that turned out to have a badly chipped lens.  I followed the discussion for a few nights and read with more than a little interest of the owner solving the problem by replacing the old lens with a Carton 80mm f/15 lens.  I forgot about it after a few days, but then one evening I found myself looking at an ad for that very same telescope, with a mouth-watering photograph of it sitting on top a very tall and solid-looking wooden tripod.  Resistance never entered my mind.  My fingers flew across the computer keyboard in response to the ad, and about a week later it arrived at my door.

The long monster showed up well packed in a solid and very heavy wooden box that I opened with devilish delight.   I worked  methodically at removing all the paraphernalia from its slightly musty temporary home, laid each part out carefully, and then whistled and hummed as I pieced it together.  Everything was there, it all worked, the tripod was every bit as stable as it looked in the photo, but the old Mizar EQ head was a rather disappointing piece of –- well -– let’s call it hardware, although even that is more complimentary than it deserved.  I passed that part on to someone at a bargain price, and proceeded to place an old Polaris mount on top of those long brown wooden tripod legs, which couldn’t have been happier.

There was one other problem I had to wrestle with –- I spied it when I bought the scope –- and that was the absence of a dew shield.

Now I live on the north Oregon coast, a part of the world that is both famous and infamous for the amount of rain it gets.  Most years see ninety to one hundred inches of rain, at least sixty percent of which falls from the sky between November and February.  But even when the rain isn’t raining, the moisture content in the air at night makes the use of a dew shield and a dew heater mandatory -– without those two items, the lens of a telescope won’t survive ten minutes before succumbing to the moisture laden atmosphere.

So I had to come up with a dew shield.  That unshielded lens looked great at the end of the scope’s cream-colored tube, but telescopic life would be impossible without it.

One day I happened to be at the local hardware/lumber store and I heard a bell ring in my head as I walked past a piece of PVC tubing.   I ran back home, measured the outer diameter of the exposed lens cell, went back to the store, and found the PVC tubing was the wrong size.  I was about to give up on the idea when I stumbled across a piece of long black plastic irrigation pipe, the same stuff used for mundane things such as sewer lines.  I yanked my tape measure out of my pocket, stretched it across the opening of the pipe ——- and it was within 1/8” of what I needed.

I had ‘em cut a piece down to size, and that’s what decorates the end of that cream-colored Mizar tube.  For some reason that pipe has a real tendency to sweat, both inside and outside, so I added some flocking to the inside of the tube, which cured the inner part of the problem.  I also replaced the focuser with a Crawford Machine Crayford single-speed model, found an old Royal Optics olive green finder that was without a home, attached it to the right side of the tube –- and made the whole thing into a demon of a double star scope.

Now due to a more infamous than normal stretch of that infamous Oregon coastal weather, this poor scope hadn’t seen starlight since last November — which was about six months into the historic rainy past.  Every time I walked past it, I could feel a restless energy radiating from it –- as in “Get me under the stars!  I’m tired of being cooped up in this house!”

So I grabbed it off its storage rack a few nights ago, put it back on top of the old Polaris mount, and marched the whole thing outside.  For some reason the altitude adjustment on the mount had slipped –- it had probably sagged in disappointed expectation of ever seeing starlight again –- so I spent some time re-adjusting and lining everything up.   And when I got done, I had an absolutely delicious, mouth-watering view of Polaris.  I believe I had a 15mm TV Plössl (80x) in the scope, and it displayed the diminutive secondary with something resembling an etched crystal clear clarity.   And the Polarian primary beamed back at me from the center of a yellow-gold diffraction ring which floated and fluctuated in a slow dance around it.  Ah, yes -– another one of  those  moments!   I lingered –- what else could I do?

An 86% full waning moon was beaming lurid rays of yellow-white light onto my right shoulder and into the corner of my right eye, so I decided to swing the scope over to the star it was named for, Mizar, and let the moon bounce its beams off the back of my head.   And again, the view was stunning.  I replaced the 15mm TV Plössl with a 24mm Brandon (50x), which had the effect of pulling Mizar’s two companions closer together.  Beautiful, beautiful, beautiful  ……………… beautiful.  Alcor sat to one side — I could swear it was admiring the view, too –- and right in the middle was Greg’s side car, also known as Sidus Ludoviciana, or Ludwig’s Star.

Then I slid sideways to Alkaid at the end of the Dipper’s handle and aimed a few degrees above it to the northeast to catch a pair of Boötean beauties, Kappa (κ) and Iota (ι) Boötis.   Both pairs of doubles decorated the field at the same time in the Brandon, but I had to look carefully to pick out Iota’s 7.4 magnitude companion (the fainter of the two secondaries), since the moon was doing its best now to turn the sky to daylight.  It was getting more than a little help from a damp haze in the air which was hard at work employing every available molecule of moisture to magnify the moon’s reflected photons.

Next I panned over to Izar and spent thirty minutes or so prying the secondary off of the primary, which I finally managed reasonably well with the 15mm Plössl, and then I looked up and saw a weak glimmer of light coming from about where Xi (ξ) Boötis was supposedly shining.   So I pointed the Mizar’s long white tube in that direction, peered into one of the finders, centered it, and then pulled up my chair and sat down for a long look.

Xi (ξ) Boötis  (Σ1888)                HIP: 72659    SAO: 101250
RA: 14h 51.4m    Dec: +19° 06′
*****  Magnitudes      Separation       PA           Latest Data
AB:      4.8,   7.0                  5.9″            306°        WDS 2012
AC:      4.8, 12.6                71.6″           340°        WDS 2008
AD:      4.8,   9.6              161.1″           286°        WDS 2008
AE:      4.8,   8.7              268.6″           100°        WDS 2009
AF:      4.8,   9.2              333.8″              41°        WDS 2009
Distance: 22.1 Light Years
Spectral Classification:  G8 (A), K5 (B)

The “D” companion can be see just to the west of the AB pair, and the two northernmost of the north-south aligned trio on the opposite side are the “F” and “E” components.  “C” was hiding behind a veil of bright moonlight.  (East & west reversed, click for a larger view).

I was still using the 24mm Brandon, and in its minimal 50x, “B” was barely separated from “A” –- which made the view all that more attractive.  The seeing was slipping slowly from a III to a II, so occasionally the secondary would get yanked back into the primary, and then it would suddenly pop loose again, where it would stay for several seconds.  My eyes roamed across the entire field, caught especially by the trio of stars in a north-south alignment just to the east of the dancing primary/secondary pair –- but they kept coming back to that dance, again and again.

After several minutes of that, I became more aware of the motion in the eyepiece.  There’s no drive on the mount, so the entire field was drifting to the west, which was to the left side of the field of view as I was situated  ——  and it impressed me as a waltz in slow motion.   And then my mind suddenly re-configured the stars in the field into the shape of a goose or a swan.  The primary/secondary pairing was the head, the three stars to their east in the north-south alignment were the wings, and further east  at a distance of about twenty-five arc minutes, were a detached pair of stars that served as the tail.

It was fascinating to sit there and watch that slow motion flight take place.   The entire field of view in that eyepiece amounts to something like a full degree –- that, coupled with the low 50x magnification, was more than enough to result in a very slow trip from the east edge of the field to the west.  I didn’t time it, but I would guess it took close to a minute for the entire configuration to wing its way across the field.

It was another one of  those  moments.

It’s uncanny how they unexpectedly dawn on you.   Suddenly  the view in the eyepiece –- regardless of whether it’s boringly normal or particularly captivating –- takes on a new dimension.   Something that was there all along, but beyond the boundary of conscious awareness, quickly blossoms into view –- and nothing about that field of view strikes you as “boring” or “normal” again.

And that’s what happened.

And when that happens, I’ve learned you don’t leave it quickly.  Your role in the continuing drama of the unfolding of the universe is to sit there at that particular moment in time and soak it all up.   And I did.   For something like thirty minutes.  I didn’t budge, I didn’t move, I barely breathed.   Just me, a 24mm Brandon, an old Polaris mount, a slow motion control, and that long, creamy white Mizar telescopic tube, pointing through the moonlight at a narrow swath of interstellar space twenty-two light years away.

P U R E   bliss!

Fire in my Fingers: 44 Boötis and its Shadow, OΣ 291

About the middle of this past April, a message from Neil English landed in my inbox, asking if I had looked at 44 Boötis, followed by a description that caused my focuser fingers to start twitching and itching.  He had resolved its 1.4” separation at 225x in his five inch Russian Tal 125 refractor, Tonya, but left me hanging from the end of my focuser when he wondered out loud if it could be resolved with a four inch refractor.  I didn’t hang there for long, though, because a few days later I received another message from Neil which featured a drumroll, and then a — “no problem!”  Using his Skylight four inch f/15, he netted a pair of crowded airy disks at 250x, and at 300x he found a sliver of black sky running between the two stars.

And of course that did it. Now I had to see it for myself – in my f/13 version of the Skylight 100mm refractor.  And I expected a tough time of it, too, because the skies above me are seldom calm enough to yield up their secrets when I try to penetrate the two arc second separation barrier.

So I proceeded to impatiently wait for the weather to cooperate, and just when I was about to give up until the middle of July, I stuck my head outside and found myself looking at clear midnight skies.  Clear, yes – at least over the upper two-thirds of the sky – but lurking around the fringes of the horizon were the familiar sinister hints of dense obscuring forms that I knew were accumulating energy enough to make a sudden lunge for the zenith.  And as it turned out, they were busy soaking up enough of a surplus to deliver a few totally unexpected surprises.

44 Boötis  (Σ 1909)     HIP: 73695     SAO: 45357
RA: 15h 03.8m   Dec: +47° 39′
Magnitudes: 5.2, 6.1  (B is variable, 5.8 to 6.4)
Separation:  1.4″
Position Angle: 63°  WDS (2012)
Distance: 42 Light Years
Spectral Classification: F7, K4

NOTE: The separation is closing quickly on this pair.  As of Jan 1st, 2017, the WDS shows it narrowing to 0.685″ at 73.8° and in 2018 it narrows further to 0.534″ at 79.0°.  By 2020, it’s down to 0.273″ at 112.0°.

Once I found my way up to my destination, I had a sneaking suspicion I had been here before.  Sure enough, after checking my Boötes files, I found I had wandered as far east as 39 Boötis back in July of last year, but stopped there since it was at the end of an extended tour through the Herdsman’s club.  So I had little problem recognizing the area, but for those who haven’t been here, I’ll be glad to provide some directions:

There are a couple of ways to get here. One is to draw a line from Kappa (κ ) Boötis to 39 Boötis, and extend it about two degrees further to reach 44 Boötis. Another way is to finish the rectangle started by the lines that run from Beta (β) to Gamma (γ) to Lambda (γ). The northeast corner of the completed rectangle will place you just to the west of 44 Boötis and OΣ 291. The first approach is shown on the chart above in yellow and the second in turquoise. (Stellarium screen image with labels added, click for a larger view).

So after overcoming the shock of seeing stars shining in scintillating midnight splendor above me, I set up my four inch refractor and aimed it into the void north of Boötes’ upper diamond-shaped framework.  And I found myself face to face with another pleasant surprise.

I could see 44 Boötis plainly enough, with no aid to my vision other than my glasses.  It was a bit faint through the atmospheric moisture left by the breezes drifting in from the ocean, but still fairly easy to see for one very basic reason – there were three stars clustered together up there, not one — as I soon discovered when I peered into the eyepiece end of the 8×50 finder on my scope (see inset in chart above)

I looked down at the Sky & Telescope’s Pocket Sky Atlas chart I was holding in my hand (it’s chart number 42 if you’re using it) – and sure enough, it showed three stars where I had expected only one.  The one in the middle was my goal, the one to the southwest was the star we’re going to look at shortly, OΣ 291, and the one to the northeast turned out to be 47 Boötis.  That one also happens to be a double, cataloged as Bu 1086, with magnitudes of 5.6 and 13.3, separated by 6.6” – more than a bit beyond my reach, I suspect, because of the wide magnitude difference.

At any rate, all three of those stars, sitting there very calmly in the eyepiece of the finder scope about half a degree apart, made for a rather stunning and unexpected sight.  And it certainly never hurts to get off to a rollicking good start when trying to shake the rust out of a pair of rain saturated eyes.

H 53, an unexpected bonus, is shown here at the upper right — the magnitudes are 8.9 and 10.9, separated by 87.2″ at a PA of 358* (WDS 1999) (East and west reversed, click for a larger view).

But it was time now to get to the serious stuff.  I surveyed the scene at 87x with a 15mm Televue Plössl – which netted me the view shown at the right — and then began reaching for implements of separation.  Now honestly, I wasn’t expecting a whole lot here – as I said, the skies just don’t surrender much around these parts except on rare occasions.   In order to keep attention focused on the object of my obsession, I wanted to stick to small fields of view, so I started with a 9mm UO Ortho, which yielded 144x.  And all I could detect was a single star, jiggling back and forth just enough to defy my efforts to bring it into focus.

UO 9mm Ortho, 144x

I settled for what seemed a reasonable focus compromise since it wouldn’t hold still for a tenth of a second – and then suddenly that vibrating image came to a screeching halt – and bless my darned damp Star Splitter hat if that single star didn’t suddenly become two stars hangin’ onto each other!

Hold on, Hannah, there’s hope up in them thar heavens tonightLet’s try that gleamin’ li’l 7.5mm Celestron Plössl!

7.5mm Celestron Plössl, 173x

We did, and at 173x, the image sprouted into a stunning figure eight!  Muchas gracias, ya li’l orange and black chrome cylinder of dee-light!

Well, now  ———

I had to pause to recover my windage and my unaccountably altered vocabulary  ———-

it was time to double up on the ocular power.

15mm TV Plössl at 2.4x, 208x

Out of the eyepiece box came a 2.4x Dakin Barlow, into it went the 15mm TV Plössl I used earlier for the wide view, and then both of them were placed carefully into the diagonal.  And at 208x, I found myself looking at the barest sliver of a hair split.  YES!

And while my right eye was hypnotically tranced over the eyepiece, I caught a sudden flash of light out the corner of the left one.  What the ………… ?

A fireball?  I looked up from the eyepiece  ———-  nothing.  Just a clear sky, the fog still hovering over the ocean, the ocean still whispering to the shoreline half a mile away — but no smoke, and certainly no fireball trail hanging anywhere in the sky.

Hmmmmm.  Well, since the night was still rollicking its way forward in good form, I swapped a 12.5mm UO Ortho into the Barlow, refocused, and at 250x ————–

I HAD A SOLID SPLIT!

Solid!  Black sky!  Between both stars!

And then there was another flash.

I looked up again.  Fireball?  Nope.  Headlights?  Nope.  Not a car in sight, nor one to be heard —- and the sky was still clear, and the ocean was still whispering away in the background …………….

What in the quasi-stellar blue blazes was ……………….. ??????

Then I remembered I had left 44 Boötis bouncing around all by itself in the eyepiece, so I went back to it, stared until I was thoroughly saturated, and as I glanced up again, I saw it – lightning!   And the sky directly overhead was still clear.  As a bell.  I got up, walked around, looked over toward the east, and I could see the clouds and fog beginning to move slowly in my direction.  Another flash, and this time it looked like it was coming from the Coast Range mountains to my east.

Well, so be it.  I’d had about three nights over the past four months when the skies were clear for longer than fifteen minutes, and it was obvious this one wasn’t going to last much longer, either.  Right now the sky above me was clear, so I wasn’t budging, lightning or not – even it if meant fire in my fingers.  And since I didn’t see any angry looking jagged bolts aimed in my direction, I put it out of my mind and went back to the telescope, stared at the miracle in the eyepiece until it started doing double-flips, and then nudged the scope over to OΣ 291.

OΣ 291         HIP:73454    SAO: 45326
RA: 15h 00.6m   Dec: +47° 17′
Magnitudes: 6.3, 9.6
Separation: 35.4″
Position Angle: 156°  (WDS 2009)
Distance: 477 Light Years
Spectral Classification: B9

Lurking in the shadow of 44 Bootis,  OΣ 291 offers a pleasant contrast in magnitude and separation  …………  east & west reversed, click for the full size view.

Now this was a pleasant contrast to 44 Boötis, and the reason was that its wider separation, along with the three magnitude difference between primary and secondary, required a different kind of hard staring into the eyepiece.  My eyes had been fixed on those two tight dancing little globes of orange light for so long, that I had to really look hard at first to pick out the 9.6 magnitude secondary of Otto Struve’s two hundred and ninety-first discovery.  But it was merely a matter of visual accommodation, and once I accomplished it, I was rather delighted with what I saw.  These two stars – 44 Boötis and OΣ 291 — really complement each other well.  By the way, if you have a surplus of telescope aperture, you’ll find a 15.7 magnitude cluster of galaxies, Abell 2018, suspended in the sky almost directly behind OΣ 291.

*********************************************************************************************

I was beginning to feel rather exposed, sitting there in the middle of my deck, hunched over a long black telescope tube capable of doing double-duty as a lightning rod — and there were still occasional flashes over in the east that seemed to be moving my way.  So I stood up, turned around to see what the state of affairs was to my southwest, and saw the sky was beginning to turn bright, which could only mean one thing: invasion of the fiendish fog.

When it comes hurtling in from the ocean, it approaches over the dimly lit downtown area in a low dive, and the few lights along the main street are reflected off of it’s damp underbelly, turning the brightness level of the night sky up by several orders of magnitude.  Actually, it’s an amazing thing to see – a pitch black night can suddenly become bright enough to almost cast shadows in less than a minute.

I could see it was also beginning to sweep in from the north and the east – in other words, I was surrounded.  And considering that there were still a few flashes over in the east, I figured the fog was really gently prodding me to pack it in for the night.  Which I did, somewhat reluctantly, but smiling nonetheless, as I thought about that dancing display of circular orange orbs I had been privileged to witness.

Now there are a couple of things about 44 Boötis that are worth circling back to retrieve.

The first is that the 6.1 magnitude secondary is a variable star.  Specifically, it’s a class W UMa variable, fluctuating in brightness from 5.8 to 6.4, with a period of 0.2678159 days – which translates into six hours and twenty-five minutes.  A plot of it’s light curve can be found here. Recent studies have also turned up what appears to be a brown dwarf orbiting the secondary, and rather brief information on that can be found here and here.

The second is the fact that the orbit of the secondary around the primary is closing fast, and by 2021 the separation will be down to 0.23 seconds of arc.  So if you want to see it, you better look quickly!  An excellent graph of its orbit can be found here (scroll halfway down the page), along with a list of the changing separation and position angle by year.  A detailed study of the convergence of the primary and secondary can be found here.

44 Boötis was actually discovered by Sir William Herschel on August 17th, 1781, and cataloged by him as H I 15.  He measured the two stars at 1.5” apart with a PA of 240 degrees, and compared them to Castor in appearance (source).  Sirs John Herschel and James South measured a separation of 2.3” and a PA of 229 degrees in 1821, Wilhelm von Struve measured 2.9” and 234 degrees in 1832, and Admiral William Smyth measured 3.3” and 235 degrees in 1834. He looked at it again in 1842, and found it had widened even further, to 3.7” at 236 degrees.  So before the middle of the 19th century, there was a general awareness that 44 Boötis was, to use the Admiral’s words, “a remarkable and highly interesting star.”  (The Bedford Catalog, p. 334)

*********************************************************************************************

While I had been busy feasting my vision on the dual orange splendor of 44 Boötis, the quiet of the night was interrupted several times by the high pitched cry of a few geese as they flew over somewhere above me.  Since they don’t sport identification lights, I had no idea how many were up there, or where exactly they were, despite the flashes of lightning.  But gradually I became aware that the few voices had become those of several flocks, and all of them were moving to the northwest, which took them out over the ocean.  I could picture them turning north once they reached the water, heading for their nesting grounds on the headlands just a few miles from where I sat, something I’ve seen them do hundreds of times in the light of day.

Now there have been more than a few nights when I’ve been serenaded under the stars by a couple of widely separated packs of partying coyotes, but I can’t ever remember a time when the geese flew in large flocks above me in the pitch black sky.  It was an eerie experience, sitting there under the stars, with occasional flashes of lightning from somewhere, while “their cryin’ voices trailed ahint them on the air —– .”

That line suddenly came to me – I had totally forgotten it – from a Scottish poem I came across several years ago.  It’s buried in the final stanza, and it’s appropriately titled “The Wild Geese”.  So by way of saying thanks to Neil for suggesting the splendorous 44 Boötis, here’s that last stanza:

And far abune the Angus straths I saw the wild geese flee,
A lang, lang skein o’ beatin’ wings wi’ their heids towards the sea,
And aye their cryin’ voices trailed ahint them on the air —–“
“O Wind, hae maircy, haud yer whisht, for I daurna listen mair!”

From “The Wild Geese,” by Violet Jacobs
The Scottish Poems of Violet Jacobs, Oliver & Boyd: Edinburgh, 1945, p. 83

Maybe the London born Skylight 100mm f/13 refractor I was peering into has a slight Scottish heritage hidden in it, or maybe there’s an uncanny quality wrapped up mysteriously in its marvelous mystique  –——- or maybe I was just fortunate to be in the right place at the right time.  Whatever it was —– it was kinda neat.

May yer skies be “maircyful” clair!  😎

Beam Me up to Boötes: 13 Boötis, Σ1834, Σ1843, and 39 Boötis

Boötes captured here as he climbs down from the meridian and begins his descent into the west with his club waving high over his head. (Stellarium screen image with labels added, click for a larger view).

Tonight we’re beaming up to a remote sector of northwestern Boötes to explore a dim, neglected section of sky that cuts a narrow swath through the middle of the Herdsman’s club.  There isn’t any blinding light from dualing doubles to be seen here — although the last one comes close — but there are certainly some subtle visual delights to be savored in this no-man’s land of sparse light.

But the first question you probably have has to do with what in the world drew me to these stars.

Star atlases are like road maps, promising unique adventures in unknown territory.  When I see the names of little known towns in the middle of nowhere on a map, I can’t help but wonder what the real thing looks like up close.  Or when I scan a U.S. Forest Service map of a wilderness area and see faint trails wandering through a maze of topographic contours, my imagination runs rampant with thoughts of the sights to be seen there.

And it’s no different when I look at a star atlas and see those horizontal lines drawn through the dots that represent stars — my curiosity soars to the surface with thoughts of what those dim points of light must look like.  That’s especially the case if I see a star that’s marked as a double, but without an identifying name next to it — which is the way the last three stars we’re going to look at here are shown in the Sky and Telescope Pocket Atlas.  Or especially if I see a star not labeled as a double when I’ve seen it referred to as one in a printed source — which describes the first one.

And that’s where we’re going now ……………………..

All four of the stars for this tour — 13 Boötis, Σ 1834, Σ 1843, and 39 Boötis — are shown here in bold. (Stellarium screen image with labels added, click on the chart to enlarge it).

13 Boötis (H VI 112)          HIP: 69068    SAO: 44905
RA: 14h 08m   Dec: +49° 27′
Magnitudes: 5.5, 11.0
Separation:  75.5″
Position Angle: 271°  (WDS 2005)
Distance: 557 Light Years
Spectral Classification: M1.5

If you draw a line from Lambda (λ) Boötis to Kappa (κ) Boötis, you’ll find 13 Boötis lying at the midway point and about an arc minute west of it.  I can pick out it’s fifth magnitude glow with both of my naked eyes working in harmony, thanks to dark skies, and it’s distinctive reddish glow is easily spotted in binoculars or a finder.

This one caught my eye because I saw it referred to in the Cambridge Double Star Atlas with William Herschel‘s distinctive designation.  In his catalog of 1782 to 1784, the Roman Numeral “VI” (6) identifies it as having a separation of between one and two arc minutes.  If William Herschel took the time to catalog it, I figured it was worth my time to look at it.

13 Boötis, a red-orange gem . . . (east and west reversed to match the refractor view, click to enlarge).

And it’s a red-orange-gold gem that is a feast for the eyes.  The secondary is a delectable dot of faint light, but is several magnitudes too dim for detecting color in the average sized back yard telescope.  I’ve found it’s easily visible in everything from an 85mm to a six inch refractor.  And a bit of averted vision in a 60mm f15 scope brought it into view several different times for me in a 20mm TV Plössl (45x), which will give you something to shoot for.

Haas doesn’t list this one in her book, and Admiral William Smyth apparently ignored it also.  But William H. didn’t, and I haven’t, and if you like red or orange or gold in your stars, neither should you!

Σ 1834        HIP: 70066    SAO: 45000
RA: 14h 20.3m   Dec: +48° 30′
Magnitudes: 8.1, 8.3
Separation:  1.6″
Position Angle: 104°  (WDS 2011)
Distance: 232 Light Years
Spectral Classification: F9

But now we move on to some sterner stuff — perilously close points of dim light in a rarely traveled star lane.  We’re going to bisect the Boötes club, so a short hop of two arc minutes due east with a slight bias to the south will take you through the lower third of it and just past its edge.  This one can be tough to find — if you get lost, note that it forms an extended right angle triangle with 6.3 magnitude HIP 69862 and fifth magnitude HIP 69951, straddling the line that runs from Lambda (λ) to Theta (θ) Boötis.  That trick has bailed me out on this one more than once.

And once you’ve found it, we’ve got some serious work to do.

When I first came across the numbers on this, I really doubted I would have much luck splitting it with anything short of six inches of aperture.  My first try was with a Meade AR-5, which has five inches of glass, and much to my surprise, this pair rolled over and surrendered without a fight.  In an 18mm Radian (66x) it was barely elongated, in a 14mm Radian (84x) it was clearly elongated, and in a 10mm Radian (118x) I found myself staring at a hair-split pair of subtle-hued yellow-white stars so close to each other that the black space between them almost wasn’t there.  The always dependable 7.5mm Celestron Super Plössl carved a dark and definite slice between the stars and served them up on a velvet black background.

The subtle and captivating beauty of a hair split star . . . east and west reversed again, click on the sketch for a larger view.

The subtle beauty of that view was absorbing, captivating, hypnotizing — a Star Splitter’s heaven even.  A good comparison is the “B-C” pairing of Σ 761  in Orion as seen in a 60mm refractor.  The magnitudes of that pair are similar, 8.4 and 8.6, but they’re much wider at 9.0″.  In the 60mm lens, though, those magnitudes are dim enough to make them difficult to separate — so in that sense, the views are uncannily similar.  More on Σ 761 and its brighter and more complex neighbor, Sigma (σ) Orionis can be found here and here.

Lured by the promise of that view, I returned the next night with my six inch f10 refractor for another small taste of heaven.  This time the two stars were touching in a 14mm Radian (109x), elongated and trying to get free of each other in a 12mm Radian (127x), and split by a bit more than a couple of hairs in a 10mm Radian at 150x, as shown in the sketch.  I had a more defined split in the 7.5mm Celestron Plössl (203x), which prompted me to try a 4mm AT Plössl.  But at 380x those two eighth magnitude stars were having trouble squeezing enough photons through the pinhole on the field stop of the lens to illuminate the other end of it, so I went back to the 10mm Radian.

Now I’ve been back to Σ 1834 several times with smaller scopes since the observations described above, and I’ve found that under category III seeing conditions, I can split it in a four inch refractor.  But it’s tight — you have to look very closely to get it, and there’s a limit as to how much magnification you can use before reaching the point where the light from the two stars becomes too faint to work with.   I almost got it with a TV85 one night when seeing conditions were similar, but there was just too much movement in the eyepiece to be sure of it.  It may be possible under much better seeing conditions.

But now that we’ve strained our eyes so strenuously on this closely separated pair of faint stars, let’s give them a rest and move on to something a bit more comfortable.

Σ 1843        HIP: 70447    SAO: 45045
RA: 14h 24m 39s  Dec: +47° 49′ 50″
Magnitudes   A:  7.7    B : 9.2    C:  9.7
Separation    AB:  20.9″        AC: 98.9″
Position Angles   AB:  180°    AC:  59°    (WDS 2011 for both)
Distance: 361 Light Years
Spectral Classification: F4

Σ 1843 is about three quarters of a degree to the south and east of Σ 1834 — and yes, it’s easy to get the numbers of these two stars mixed up.  And I’ve found it can be a difficult one to locate as well, despite its short distance from our previous star.  The best visual aid is to look at it as the first in a short arc of three stars — seen in the last chart above, or the one below– as you move slightly southeast towards it.

Now if you just happened to stumble across this compact little triple star without knowing what it was, you would probably make a quick mental note of it and keep going.  But after I spent a prolonged period of time dissecting Σ 1834 in a very confined and restricted circle of space, this was really a welcome contrast — the difference was immediate and obvious.   When my eyes took in the wider separations of the three stars, I felt like I was cavorting in an open field.

Σ 1843 is a compact triple sporting more space than it may seem at first. Click for a larger view, east and west reversed once more.

My first sighting of it was with the AR-5 in an 18mm Radian (66x).  All three stars were easily seen, but I needed to look up the position angle of “C” in order to distinguish it from another star of similar magnitude located about the same distance to the northwest of the primary.  The primary I saw as white, and I was able to pick out a slight tint of reddish-orange in “B” — no luck with seeing color in “C.”

At magnitudes of 9.2 and 9.7, the “B” and “C” components can be difficult to pick out in a 60mm scope.  In the Lafayette 60/800 I have mounted on the AR-5, I needed to look closely with a 20mm TV Plössl (40x) to see the AB and AC splits.  With a 15mm TV Plössl (53x), AB was a very tight pair and “C” almost faded from sight without the use of averted vision.  I tried a couple of .965″ eyepieces in that scope and found I needed averted vision to separate “A” from “B” in an H20mm, but it was easy with direct vision in an HM12.5mm (64x).

I swapped those two little eyepieces into the AR-5 for a quick look and was really struck by the difference in the view.  Everything I could see in the 18mm Radian was visible in the two .965″ eyepieces, but the tighter radius of the field pulled everything into a more compact circle, shrinking the already diminutive points of starlight as well.  A different experience, but one worth repeating.

A smaller version of the previous chart, just to make your tour a bit easier. 😉 (Click to enlarge!)

39 Boötis (Σ 1890)
HIP: 72524   SAO: 45231
RA: 14h 49.7m
Dec: + 48° 43′
Magnitudes: 6.3, 6.7
Separation:  2.5″
Position Angle: 45°
(WDS 2010)
Distance: 229 Light Years
Spectral Class: F6, F5

Now we’ll leap about three degrees to the northeast and get clear of this club the Hunter is waving in the air and reward ourselves with a brighter and more colorful pair of stars.  Draw a line from Σ 1843 so that it goes midway between 6.5 magnitude HIP 71235 and 5.7 magnitude HIP 71280 and it will take you right to 39 Boötis.

Admiral William Smyth approached it from Polaris, however, by extending a line to Beta (β) Ursa Minoris, also known as Kochab, “and prolonging it just as far again.”  (The Bedford Catalog, p. 329)   That works, although the distance from Polaris to Kochab is about fifteen degrees, and from Kochab to 39 Boötis is a bit more than 25 degrees.  You’ll need dark skies to see it, however.  Mine are normally dark enough that I can just pick it out with averted vision, but using the finder on the scope or a pair of binoculars is less strain on the old naked eyes.

As you’ll notice right away, this pair is considerably brighter than anything we’ve looked at so far.  Two things add to its beauty — its color and the close separation of the two stars.  Although, as Haas notes, they’re not too close for a 60mm scope:

Showcase pair.  60mm, 120x: A pair of touching twins, whitish gold in color, that are just bright enough for a 60mm to show them sharply.”

“Showcase pair. 60mm, 120x: A pair of touching twins, whitish gold in color . . .” but shown here with a bit more space between them as seen in a six inch refractor. Click for a larger view.

She credits Webb with seeing white in both stars, and Admiral Smyth saw white and lilac, which must have been his favorite color, one I have yet to see in a star.  What I did see, though, was identical colors in both stars — gold with a slight tint of red.  At any rate, the brighter and richer colors were a welcome sight in comparison to the prior stellar sightings.

My 60mm f/15 Carton lensed scope was just able to pry this pair apart with the aid of an 11mm TV Plössl at 82x, and at the time I tried, the seeing had started to deteriorate to the point that there was no sense in adding more magnification.  I also managed a clean split in a TV85 with a 6mm Celestron Ortho (100x), but the advantages of aperture were apparent in the 152mm f/10 refractor.  As the sketch shows, both components were clearly separated at 127x in a 12mm Radian.  But it was their color that really grabbed my attention — a soft, glowing gold that gleamed against a very dark sky.  If it hadn’t been for the vibrations caused by the seeing conditions, I almost would have thought I was looking at a painting.  A real pleasure, especially after the dim terrain we’ve been picking our way through up until now.

And that pretty well puts a Star Splitter’s cap on a wonderful series of nights I spent searching this area.  I must have gone back half a dozen times to look at these four stars with apertures ranging from sixty to two hundred millimeters, and to familiarize myself with the territory.  I can throw away the map for it now — it’s imprinted so well in my memory, I should have no problem negotiating through it again in another month or so.

Thanks to the cooperation of the sun, we’re entering the time of year now when darkness begins just a bit earlier each evening — and that has the effect of almost suspending the westward march of the constellations since it’s possible to begin viewing a bit earlier each night.  So Boötes will still be perched in the southwest shortly after dark, beckoning to me with his club.

And resistance is futile.

Clear Skies!

Captured by Color: The Multiple Thrills of Xi (ξ) Boötis

What in the world is it about some of these stars that keeps me glued to the eyepiece for more than an hour at a time?  This one I found to be irresistible, magnetic, stunning — heck, it was even charismatic in a chromacolor sort of way.  It really was that good.

Boötes, the Hunter, on the hunt for a colorful pair of stars. (Stellarium screen image with labels added, click on the image to enlarge)

I have no idea now where I first came across a reference to Xi (ξ) Boötis, but at a visual magnitude of 4.7, it’s one of the many gems of the sky that glow in the dim fourth and fifth magnitude range that escapes easy visual detection — yet it’s relatively easy to pick out of a reasonably dark sky once you’ve identified its location on a star chart.  I really wish I knew how many more are twinkling up there in relative obscurity — there must be hundreds.

Fairly easy to locate, it can be found about eight degrees due east of Arcturus, or about the same distance directly south of Izar, since it occupies one corner of an equilateral triangle anchored by all three stars.  I was going from memory when I aimed a TV85 at it, and I landed on Omicron (ο) Boötis instead, which absolutely would NOT split.  And for good reason, too — it’s only a single star.  🙂

But that dim light came on upstairs soon enough.  I looked at a chart,  moved a few degrees to the northeast — and when Xi (ξ) hovered into view, my hour of stellar bliss began.  Wow.

Xi (ξ) Boötis forms an equilateral triangle with Izar to its north, and Arcturus to its west. (Stellarium screen image with labels added, click for a larger view)

Xi (ξ) Boötis  (Σ 1888)        HIP: 72659    SAO: 101250
RA: 14h 51.4m    Dec: +19° 06′
*****     Magnitudes           Separation         PA         Latest Data
AB:      4.76,   6.95                 5.6″            302°        WDS 2015
AC:      4.76, 13.83                69.9″           342°        WDS 2015
AD:      4.76, 11.73              158.6″           286°        WDS 2015
AE:      4.76,   8.65              271.5″             98°        WDS 2015
AF:      4.76,   9.20              337.5″             37°        WDS 2015
Distance: 22.1 Light Years
Spectral Classification:  G8 (A), K5 (B)

NOTE: Magnitudes, separations, and PA updated to match current WDS as of 12/2/2016

My instrument of first approach was a 12mm Radian (50x), which prompted me to sit up straight and look closely.  At first glance, I saw only a single star, but with a bit of intense staring, the very small dot of the secondary revealed itself.

The larger one beams back at you with a soft and pale radiance, the smaller one gleams very intensely and richly . . . (East and west reversed to match refractor view — TIP: turn off the lights for a better view!)

This was really a splendid sight — the primary was a light shade of glowing red with a touch of orange, and there was just enough white mixed in to lighten up the overall color.  The secondary was an intense little spot of light virtually identical in color, but much richer.  The contrast between those two colors reeled me in so quickly I didn’t know I had been hooked.

The reported colors on this star have been all over the place.  In a 60mm at 25x, Haas describes it as a “bright white star touching a vivid little gray star.”  I haven’t seen it in a 60mm scope, but I’m curious as to whether I’ll see the same colors.  She credits Webb with “yellow, purplish red,” and Hartung with “yellow and deep orange,” which was at least closer to what I saw.  The always quote-worthy Admiral Smyth described it in The Bedford Catalogue as

“A binary star, in the left knee of Boötes; being the northernmost of the four stars forming his leg, and 10° east of Arcturus.  “A” 3 ½, orange; “B” 6 ½, purple; the colors in fine contrast.”   (p. 328)

And somewhere I saw a reference to it as red and blue.

In comparison to the sun, these two stars are somewhat of a rarity, having both less luminosity and less mass than our star.  It’s their relatively close proximity to us that keeps them from being out of reach of my telescope, and is responsible for the dazzling show I saw.  More on Xi (ξ) can be found here  on Jim Kaler’s Star Site.

But to get back to the current observation  —-  with the seeing wavering between average (III) and medium poor (II),  I couldn’t see any reason not to try a 10mm Radian (60x).  That pried the two stars apart just a slight bit more, leaving me hungry for a larger slice of dark sky, so I reached down into my eyepiece box and pulled out an 8mm Radian (75x).

Ahhhhhhh   …………   that went a long way toward curing my craving.  But as usually happens after appetite appeasement, I developed a strong thirst.  So my right arm reached down into the depths of the eyepiece box and came out with a 6mm Radian — and 100x.

What blessed bliss!  I traversed that field of view several times, lingering over every visible star in it, and in between traverses, I took another drink of those vibrant colors.

Located about five arc minutes east of the primary is a trio of ninth magnitude stars oriented on a north-south line which kept calling to me.  They reminded of me another stellar sight I’ve spent many an evening or morning with, Eta (η) Persei.  Like this one, it also has a distinctive reddish glow which is very appealing, and it also has a line of three stars spread out in a row opposite the primary, but on the west side instead.  And it’s a multiple star as well  ………….

……….  which I’ve neglected to mention so far.  Stunned as I was by the view, I still couldn’t help but suspect that some of the dim stars surrounding Xi (ξ) could be companions, but the data I had at that moment only provided the statistics for two stars.  So the next morning I checked that old standby, the Washington Double Star Catalog, and found Xi (ξ) had another four companions scattered around it!  I was able to go back to the sketch I had made and identify all of them except for “C.”  At a magnitude of 12.6, it might be within reach of the TV85, but I really think the separation of 71.6″ is close enough for it to drown in the glow of the primary.  Shouldn’t be any problem with four inches of aperture or more, though, so I’ll try again on the next clear night.  In a six inch scope, it should even be possible to detect some color in the “D,” “E,” and “F” companions.  (I did pry “C” free from the glare a few days later, and added the inset at the lower right to the sketch above — see the first comment below).

And I discovered something while I was sketching this star field.  I was using a red flashlight with an adjustable dimmer, but as I’ve found many times before, despite keeping the light as low as possible, it still affects my dark adaptation just a bit.  Not for long, but enough that when I leaned back over the eyepiece, it took about fifteen to thirty seconds to get back to normal.  What I noticed, though, was when I first looked into the eyepiece, the colors of the primary and secondary were richer and the background sky was blacker.  I suppose that’s not surprising, considering the slight loss in dark adaptation, but the effect is mesmerizing.  If I hadn’t been hooked already, I certainly was now.

So imagine a velvet black background that is as devoid of light as it can be.  Glowing at the center of it are two red-orange dots of light — the larger one beaming back at you with a soft and pale radiance, the smaller one gleaming very intensely and richly at very close to the same color.  Now try to pull yourself away from it and go on to another star.

I tried.

But I couldn’t.

Believe me, I tried about a dozen times — but every time I pulled back from the eyepiece and looked up at my next target, I was consumed with a craving for another round of those vibrant reddish-orange photons.  So back to the eyepiece again  …  and again   ……..   and again    …………..    and several more agains.

And when I finally did succeed in overcoming Xi’s (ξ) magnetic pull, it was to take a peek at Izar — another reddish-orange star.

What can I say  — I’m probably a few hundred thousand parsecs past hope.  😉

Under the Influence of Arcturus: Pi (π) Boötis, Eta (η) Boötis, Σ1772, Σ1825, S 656

Boötes, the Herdsman, shown here reaching for the sky. (Stellarium screen image with labels added, click to enlarge)

Boötes seems to have more than its fair share of double stars — I can easily count about thirty of them on the main Boötes chart of the Cambridge Double Star Atlas, and there are at least ten more to be found around the fringes of a couple of other charts.   I can’t help suspecting that when The Herdsman is hidden from sight in the daylight, or lurking on the opposite side of the globe, he’s busy dealing for double stars with his neighbors.  At any rate, if you’re in search of multiple stellar scintillation, this can be a particularly productive happy hunting grounds.

On the other hand, if you like your stellar scintillation singular and on the particularly bright side, Arcturus really deserves a place at the top of your list.  It gleams at a brilliant magnitude of 0.2, making it the fourth brightest star in the sky.  Located a mere thirty-seven light years from where we orbit our own star, it’s surrounded by five very intriguing multiple stars that are under the influence of its soft glowing orange light.  Three of them are doubles, one is a triple, and there’s even a quadruple hiding here.

And when you invoke some of the Greek terminology in this group of stars, such as Eta (η) and Pi (π), it’s possible to work up an appetite.  Consider this conversation that might be taking place right at this very moment between two Arcturians:

“So, Blârgörkh, may I inquire as to what you ingested for an after dinner supplement this opulent orange evening?”

“I Eta Pi.”  (I η π)   …………………..

…………………..    But we better move on.   🙄

We’ll start this tour in the west and work our way back to the east — and yes, there’s a good reason for picking this direction.  The first night I went in search of these five objects, I started in the east and before I could get to Σ 1772 and S 656, they were swallowed by a cluster of ravenous coastal pines.  So if you have similar obnoxious obstructions to wrestle with, this will help to avoid them.

And now    ……   on to Arcturus!

We’ll use Arcturus as a base for this star hopping adventure since it sits pretty much at the center of our search area — and anyway, on a dark night it’s comforting to have it’s orange light nearby in case we get lost. (Stellarium screen image with labels added, click for a larger view)

Eta (η) Boötis (Muphrid) (SHJ 169)         HIP: 67927    SAO: 100766
RA: 13h 54.7m   Dec: +18° 24′
Magnitudes: 2.7, 10.0
Separation:  113″
Position Angle: 86°  (WDS 2011)
Distance: 37 Light Years
Stellar Classification: G0

We’ll start with Eta (η), also known as Muphrid, also known as SHJ 169, and located four degrees west of Arcturus.  At a magnitude of 2.7, it’s the third brightest star in Boötes, so it would deserve a bit of recognition even if it wasn’t drawing our Star Splitting attention.  Besides being located at about the same distance from us as Arcturus, it has begun to enter the “red giant” stage, so one of these days it will rival Arcturus in brightness.  As far as the name goes — well no one really knows.  It’s ancestry is Arabic, but beyond that, it’s a bit obscure.  So we’ll leave it that way for now, although more information can be found on Jim Kaler’s Star Site.    And, if you’re wondering about the SHJ designation, that comes from it’s place in James South and John Herschel‘s joint catalog of 1824 — on some star maps you’ll see the prefix “Sh” used instead, as in Sh 169.

I sketched this while trying to peer through an insistent towering cloud hovering in the southwest, so there may be a few stars less here than what you would see in a four inch refractor under better conditions.  (East & west reversed to match the refractor view).

I sketched this while trying to peer through an insistent towering cloud hovering in the southwest, so there may be a few stars less here than what you would see in a four inch refractor under better conditions. (East & west reversed to match the refractor view).

This is an easy, wide double, although the tenth magnitude secondary can be a bit tricky if the moon is full.  Fortunately, my first night with this one was about thirty minutes before a very bright waning moon rotated over the horizon.  In my six inch f/8 Celestron refractor at 87x, the primary was a light shade of orange with a bit of white in it.  The secondary was way too faint for seeing color, but otherwise it was no contest to find.  Admiral Smyth  saw “pale yellow” in the primary and “lilac” in the tenth magnitude secondary — but I can’t imagine how.   Haas describes the primary as “Sun-yellow,” and the secondary as “a misty little dot.”

Faint  and misty would be a better description of it.  In my 60mm f/13.3 refractor it’s tenth magnitude dimness performed a dance of disappearance and reappearance.  I had a glimpse of it in a 20mm TV Plössl (40x), lost it completely when I moved up to its 15mm sibling (53x), but got it back again with the 11mm (73x) TV Plössl.  Then I had the brilliant idea that dropping back to a 24mm Brandon (33x) would defeat the glow and allow that tenth magnitude dim dot to pop into view  ……  but it didn’t quite work out that way.  It was as baffling in the Brandon as it was in the 20mm Plössl.  The seven magnitudes of difference in brightness between the two stars was really stretching the optical limits of the small refractor, so I patted it on the objective,  said “good job,” and gave it a rest.

Σ 1772  (1 Boötis)          HIP: 66727    SAO: 82942
RA: 13h 40.7m   Dec: +19° 57′
Magnitudes   AB: 5.8, 9.6     AC: 5.8, 11.9     AD: 5.8, 7.4
Separation    AB: 4.5″            AC: 87.3″           AD: 208.4″
Position Angle   AB: 133°     AC: 25°              AD:  1°
Data    AB: WDS 2010     AC: WDS 2001      AD: WDS 2010
Distance: 303 Light Years
Spectral Classifications:  A1 for all three components

Now if you take a peek in your finder (or look at  the second chart above) you should see two stars, 7 Boötis (magnitude of 5.7) and HIP 67521 (magnitude of 6.8),  just southwest of Eta (η).  These two form a line that points northwest to our next star, Σ 1772.  And a stunning little four-ple it is, too.

I had a mere glimpse of this one in the six inch Celestron about a week prior to the observation shown in the sketch, but it was inhaled by the pine trees and all I was left with was a tantalizing taste of what could have been.  So I was more than eager to get back to it the first time the clouds parted, which took well over a week.  Was it worth the wait?  Is Jupiter a gas giant?

Yes, and Yes!

View to match that in a refractor once again. Look closely or you’ll miss “B”! (Click to enlarge)

Now this one isn’t over-poweringly bright, but it kind of pulls you in by catching your eye with it’s two white wonders, “A” and “D”, which Admiral Smyth described as “sapphire blue” and “smalt blue.”  And if you look closely, you can even pry 11.9 magnitude “C” out of the darkness in a 60mm refractor with some judicious use of averted vision — provided you have dark, reasonably transparent skies.  I couldn’t see it in my 60mm f/16.7 at 50x, found it at 67x with averted vision, and lost it again at 91x — another dance of disappearance at the outer limits of the optical twilight zone.

But I recognized immediately that something was missing — 9.6 magnitude “B!”

Now, you would think that even with almost four magnitudes of difference, 4.6″ would be enough separation to spy this uncooperative companion with relative ease — or at least I did.  And I really should know better by now — call it a case of over zealous zeal.  Invoking the 2.51 rule — meaning each decrease in starlight of a full magnitude reduces the visible light by a factor of 2.51 —  we find that “B” is about 39 times dimmer than “A” (that’s 2.51 to the fourth power).  Now really, that still doesn’t seem like a lot, especially considering that for the star we just looked at, Eta (η), the tenth magnitude “B” component is 628 times dimmer than the primary.  But we’re not helped at all by the fact that this 9.6 magnitude “B” is little more than a diminutive dot of light — and 4.6″ is nowhere near far enough away for that pinpoint of light to escape the glare engulfing it from “A.”  So what all that adds up to is the fact that “B” is a bit of a battle.

In my six inch Celestron with an 18mm Radian (68x), I had a hint of it.  Moving up a few notches to a 14mm Radian (87x) was enough to grab it from the glare, and as the sketch shows, it surrendered a solid split to a 2x Barlow loaded with a 24mm Brandon (101x).  It still seemed to need more distance, though, so it was a real stroke of inspiration when I pulled the 15mm TV Plössl from it’s perch in the diagonal of the 60/1000 and dropped it into the Barlow.  That allowed a leap skyward to 162x and a nice slice of black sky between the two stars — but as usual in my seeing challenged skies, it was hopping and twisting and diving and lurching and fidgeting and vibrating so much it was more than my eyes could keep track of for long.

So I backed off to the 14mm Radian again and just absorbed the view for another few minutes, until I glanced up and saw the approaching trees beckoning with their boughs …………….

S 656          HIP: 67543    SAO: 83022
RA: 13h 50.4m   Dec: +21° 17′
Magnitudes: 6.9, 7.4
Separation:  86.9″
Position Angle: 208°   (WDS 2011)
Distance: 338 Light Years
Spectral Classification: G0

…………….  and I decided I better get moving before S 656 was gobbled up again.

Now this is another one of those situations where I found myself attracted to the configuration of the stars in the field of view more than the double star itself.  After sliding two degrees to the northeast in the 8×50 finder, I leaned over to look in the 20mm TV Plössl (50x) sitting in the 60mm scope, and found my eyes drawn immediately to the two stars at the center of the field — and the one to the west, and the one to the east.  There’s really little else in the field of view to compete for your attention.

6 Boötis is shown at the lower middle left in this sketch, HIP 67591 is at the upper middle right. (Click for a larger view).

If you look at the sketch, you can see that the “B” component of S 656 forms a line with 4.9 magnitude 6 Boötis to it’s west, and the “A” component forms a parallel line running in the opposite direction to 8.5 magnitude HIP 67591.  Six Boötis is a beautiful star in it’s own right — a reddish-orange class K star located 368 light years from us.  It’s partner on the opposite side of the field of view is notable for it’s distance, 1424 light years — which helps explain it’s lesser stellar magnitude.

But, this is about double stars, and James South’s  catalog number S 656 is no slouch.  Both stars are white, although there seems to be enough of a tinge of yellow in them to subdue the white light and lose the glowing headlight effect you get in bright class A and B stars.  This is really a view that is ideal for a 60mm scope, but it doesn’t lose anything in a larger aperture, either.  In the six inch Celestron, the subdued white glow of the “A” and “B” components is a rather remarkable contrast with the reddish-orange hue of the significantly brighter 6 Boötis.

So take your pick — sixty millimeters or six inches, or anything in between — and allow your eyes to relax in the expansive field of view as the photons of these four stars nourish your neurons.

Σ 1825           HIP: 69751    SAO: 83259
RA: 14h 16.5m   Dec: +20° 07′
Magnitudes: 6.5, 8.4
Separation:  4.2″
Position Angle: 154°   (WDS 2012)
Distance: 105 Light Years
Stellar Classification: F6

Now this one  …….  this one is a star of a different color.  But at a degree north of Arcturus, it’s easy to find.

I’ll turn it over to Haas first:

125mm, 83x: A fine star that’s nicely placed.  It’s a bright amber-yellow star almost touching a little silvery globe.  Easily spotted just outside the viewfield of Arcturus, which is about one degree to the south-southwest.”

Now my color perceptors didn’t quite see it that way  —  they reported orange and blue-white.

But regardless of color, I had to look real close to see two stars . . . click to enlarge.

But regardless of color, I had to look real close  to see two  stars.  It’s not that it’s a difficult double, but I had spent so much time soaking up the wide, comfortable field surrounding S 656 that it took a few moments to force my eyes back together in order to focus on the center of the field.

I came back to this one a few nights later, when my eyes hadn’t been widened by S 656 and it’s associates, and came away with a totally different impression.  I was using my six inch f/10 refractor on a night with very stable seeing (IV) and transparency that was almost as good — and found the view in an 18mm Radian (84x) was simply beautiful.  That little silvery globe that Haas saw was nestled right up against the primary at a bit more than hair split distance — and it struck me as a very delicate jewel of silver-blue light.  This pair of stars pretty much dominates a fairly sparse field, although there is an interesting pattern of tenth and eleventh magnitude stars stretched across it to the north and west.

And if you look closely and carefully, that silvery little globe can be glimpsed in a 60mm f/16.7 scope at 50x  — but you gotta peer pretty intently to catch it.

Pi (π) Boötis   (Σ 1864)  (H III 8)          HIP: 71762    SAO: 101139
RA: 14h 40.7m   Dec: +16° 25′
Magnitudes   AB:  4.9, 5.8    AC: 4.9,10.6
Separation    AB:  5.4″          AC: 127″
Position Angles    AB: 111°  (WDS 2010)      AC: 163°   (WDS 2009)
Distance: 317 Light Years
Stellar Classification: B9, A6

And now, if Blârgörkh hasn’t eaten it, we’ll head for the highlight of this tour.

Zeta (ζ) Boötis is located at the joint of the Hunter’s eastern knee, and Pi (π) is just a short two and half degrees north of it.  Easy as pie  …..  or a piece of cake  …..  depending on what you’re having with tea after this tour.

. . . this gleaming white pair of stars with a whisper of gold in the primary . . . (Click to enlarge)

. . . this gleaming white pair of stars with a whisper of gold in the primary . . . (Click to enlarge)

Now this one IS a pair of headlights coming at you on a dark highway, especially if you’re using four or more inches of aperture.  I don’t know where it’s been all my life, but if someone had introduced me to this gleaming white pair of stars with a whisper of gold in the primary a few decades ago, I would have become engaged on the spot.  They really are an attention grabber.  At the other extreme, the faint 10.6 magnitude “C” companion is easy to overlook — although at a respectable distance of just over two arc minutes, it’s visible in a 60mm scope with a bit of averted vision under dark skies.

But the A-B pair is a very attractive sight in a 60mm scope as well, which is what Haas was using when she described them as a “showcase pair . . . split by a hair at 35x.”  My experience was the same, in both a 60mm f/15 at 46x and a 60mm f/16.7 at 50x.  The beauty of the 60mm aperture is that it forces you to look closely to see the split.  And if you do, what you’ll see are two very sharp, very well defined gleaming white stars that are so close together they couldn’t be any closer and still be separate.  And that kind of split in a 60mm scope ranks right at the top of the many optical delights I’ve experienced.

Now if you had been splitting stars with the Herschels two hundred years ago, you might not have seen it that way.  Jim Kaler writes that these two stars were about two seconds of arc further apart when William Herschel first observed them back in those pre-headlight days.   But even then, they must have been a blinding sight in that huge reflector.  (Click on the photo that comes up at the top of that page and you’ll get a much better view of the scope).

I’ll be returning to Pi (π) every time I have a clear sky this summer — in fact, I’ve already been back back to it a couple of times since the night I made the sketch.  The brilliant white light escaping from these two white suns just begs to be captured in the circular confines of a telescope tube.

Next time out — wide wonders and perilously close points of light in the northern reaches of Boötes!

……….  and since that ravenous Arcturian, Blârgörkh, left a piece of pie (π), I’ll go grab it while he’s practicing his Greek.

May your skies be clear and strewn with doubles of delight!  😎

(WDS data updated 7/16/2013)