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Cavorting with Caph: Part 1 – Caph’s Acolytes: MLB 36, SCA 1, and SMA 2

Actually, to put things in the proper order, what happened was Caph captured me first with a promise of a string of six of clear nights.  That would be enough to entice any cloud-cursed Star Splitter . . . . . . so before I even knew I was a compliant captive, I found myself cavorting though its star-silvered surroundings to my heart’s content.

I really should shed some Sirius serious light, though, on how and why I was captured by this rather run-of-the-mill example of a solar furnace.  After all, it’s just your average class F star (F2 to be more precise), which means it should mainly appear white with a hint of yellow — but every time we met I was struck by its slightly tarnished gold hue.  And it’s not what you would call a showpiece double — not with its pair of 11.3 and 13.7 magnitude companions squinting back at you through the glowing ether surrounding Caph.  And compared to the other principal stellar characters in Cassiopeia, it’s only the second dog in the pack, meaning it’s the Beta (β) of the constellation, not the Alpha (α).

You have to turn to its multi-talented supporting cast to unlock the secret:

Caph is seen here at the center of its surrounding brood of stellar relatives. You’re going to see it a few more times, so you can memorize all those locations a little later. (Stellarium screen image with lots of labels added, click for a full frame view).

Not only is Caph surrounded by silver star dust, but no less than fifteen of the stars that illuminate all that stellar class dust are double, triple, or quadruple stars that lie within reach of a five or six inch telescope.  And even more amazing, they’re all within a single finder field of Caph.  Whereas most 8×50 finders have roughly a five degree field of view, the circle in the chart above is only about three degrees in diameter.  But we don’t even need that much space, since Caph’s supporting cast are all within a 1.3 degree radius of its yellow-gold glow.  So regardless of what finder you might happen to have, they all should fit quite comfortably into its field of view.

Add Caph and its two companions to the mix, and you have a total of sixteen multiple stars waiting for you to pull up a chair and pay them a visit.   Some of them are easy to converse with, some are a bit difficult, and a couple can be a little challenging at times — but each of them is possessed of distinctly different personalities.

So now that you know the how and the why, it’s time we commenced to cavort!

Caph — Beta (β) Cassiopeiae  (AGC 15)           HIP: 746    SAO: 21133
RA: 00h 09.2m   Dec: +59° 09′
Magnitudes   AB: 2.30, 13.70    AC: 2.30, 11.30
Separation    AB: 66.10″             AC: 344.50″
Position Angles  AB: 268° (WDS 2007)   AC: 318°  (WDS 1999)
Distance: 54 Light Years
Spectral Classification: F2

Since Caph is the centerpiece of this series, we’ll put it at the center of our field of view right now and bring it into sharp focus.  You’ll have to excuse its glare, though — it has a tendency to radiate excessively in an exuberant wavelength.

Admiral Smyth described the “C” companion as an “acolyte”, which certainly seems to fit it. (East & west reversed to match the refractor view, click on the sketch for a better view).

(STSci Photo, click to enlarge)

Now missing from the sketch is Caph’s over-powering glow.  You can get a better idea of it by clicking on the inset at the right, although the glow there is actually worse than it appears in the eyepiece.  Add the sketch and the photo together, divide by two, and you’ll come close to the eyepiece view.

The trouble with all that glowing ether, of course, is it hides the 13.7 magnitude “B” companion completely.  I’m not certain it’s visible in the photo, either, although there are a couple of possible candidates there.  On the other hand, 11.3 magnitude “C” was easy enough to identify once I used MegaStar to measure the distances on my sketch and in the photo.

I was better able to fathom my mysterious attraction to Caph when I decoded the initials of the identifier attached to it in the Washington Double Star Catalog (WDS), AGC 15.  It just so happens those three letters belong to Alvan Graham Clark of Alvan Clark & Sons (he was one of the suns sons), the optical artists who created the famous Clark refractors during the last half of the 19th century.  With what must have been a sharp eye and a great lens, he discovered the 13.7 magnitude “B” companion in 1889.

Clark’s double star career started with the discovery of Sirius “B” in 1861, now cataloged as AGC 1 in the WDS.  At the time, Sirius “B”, an 8.5 magnitude white dwarf, was 10.4″ from the bright white primary, blazing away brilliantly at an over-powering magnitude of -1.46.  Just to confirm A. G. Clark’s visual acuity on Caph and Sirius “B” was no fluke, he also ferreted out Sirius’s 14.0 magnitude “D” component in 1865, when it was 44.3″  from that overwhelming minus magnitude glare.  The 15.46 magnitudes of difference between the two stars means the “D” component is about 1.4 million times fainter than the primary (2.5115.46, or 2.51 to the 15.46th power).

Getting back to Caph, I was left wondering who discovered its impossible to see 11.3 magnitude “C” companion.  The WDS lists the first date of observation for Caph as 1838, which coincides with Admiral William H. Smyth’s observation listed on pages two and three of The Bedford Catalog.  And sure enough, that observation identifies the “C” companion for what appears to be the first time (a search through the catalogs of both Herschels, both Struves, and James South came up empty).  Even though he supplied both a position angle (339.6 degrees) and a separation (201.0″), the loquacious Admiral seems to have received no lasting credit for it.  At the least, it deserves the label of WHS 1 – for which I officially nominate it now ….. unofficially.

There are two more double stars in that sketch above waiting to be excavated from Caph’s exuberant glare, so let’s cavort northwesterly to MLB 36.

MLB 36         SAO: 21121  (No HIP number)
RA: 00h 08.2m   Dec: +59° 13′
Magnitudes: 9.8, 12.1
Separation:  7.4″
Position Angle: 359°  (WDS 2008)
Distance: ?????
Spectral Classification: B9
Discovered in 1910 by W. Milburn, who served as an assistant to T.H.E.C Espin of England

This one took me for quite a spin.  If you look at both the photo and the sketch above, you’ll see a 10.8 magnitude star which is about 45″ to the northeast of MBL 36.  I couldn’t see a secondary shadowing either that star or the one that proved to be MBL 36, so I turned to my computer and dug out the photo of the Caph area shown above at the right.  Sure enough, if you look carefully, you can see a small dot of light budding from the 9.8 magnitude primary of MLB 36 at the correct position angle (that photo is slightly tilted to the northeast).

Back to the telescope I went, with intentions of pushing the over-exuberant Caph out of the scene.  By sliding it out of view to the east and using the narrow field and high magnification of a 5mm Radian (240x), I was able to clearly see the 12.1 magnitude secondary that was visible in the photograph.  Once I had that secondary pinned down visually, I found it was possible to get distinct glimpses of it in the 12.5mm Astro-Tech Plössl I used for the sketch, even when Caph was positioned at the center of the field of view.

There’s still one more double star sitting up there in that sketch of Caph, which is:

SCA 1         (No HIP or SAO number)
RA: 00h 09.7m   Dec: +59° 00′
Magnitudes: 11.3, 12.3
Separation:  14.2″
Position Angle: 269°  (WDS 2001)
Distance:  ?????
Spectral Class: ?????

And as you can see, there seems to be a dearth of data for some of these stars — rather hair straining, especially since it plays havoc with my proclivity for interstellar spatial orientation.  Knowing a star’s distance, even if only an approximation, satisfies an uncanny need I seem to have for knowing where that star is in relation to where I am.  At any rate, I’ve mined all the sources I can find for both the distance and spectral classification, with absolutely no luck.  I didn’t do much better with this star’s identifier either, other than to find some references to papers published by M. Scardia, an astronomer based in Cambridge, England, who has quite a lot of research on stellar objects credited to him.

But of course the real reason for discussing this star has to do with the challenge of separating the secondary from the primary.  And to do that, I had to politely push Caph out of view once again, and when I did, I was able to get this view:

SCA 1 is barely out of Caph-range near the north edge of the field.  (East & west reversed once more, click on the sketch for a larger view).

You can see the SCA 1 pair is positioned at the right edge of the field of view in the sketch, which is because Caph was barely out of view at the right (northwest).  Moving SCA 1 toward the center of the field of view brought Caph’s glaring glow back into play, which tended to make the 12.3 magnitude secondary vanish from view.  Even in this 15 arc minute diameter field of view, I was barely able to find enough space for the SCA-1 pair to shine separately.

And no, it’s not the most rousing double star view I’ve ever seen, BUT  —–  the mere fact that I can sit on a deck in the northwest corner of Oregon and stare who-knows-how-many light years into interstellar space and separate a pair of eleventh and twelfth magnitude stars fourteen-point-two seconds of arc apart, both of which are billions of times fainter than our own star as seen from my deck in the daylight . . . . . . . . . . . . . . . sometimes it’s not all that hard to find yourself awed and humbled at the same time.

There’s one more star hovering within radiating range of Caph, and that’s another obscure little devil, better known as:

SMA 2     (No HIP or SAO number)
RA: 00h 06.4m   Dec: +59° 00′
Magnitudes: 11.1, 12.1
Separation:  13.7″
Position Angle: 261°  (WDS 1999)
Distance:  ?????
Spectral Class: ?????

To get to SMA 2, which is situated about 23 arc minutes to the west and slightly south of Caph, I had to persuade Caph to leave the field of view once more, which it did for the third time with one last stellar glare.  By gently pushing Caph to the east edge of the 22 arc minute field of view of a 14mm Radian (109x), I could see SMA 2 begin to appear on the opposite side of the field (west).  Another nudge and Caph disappeared as SMA 2 took up residency at the center of the field in a 10mm Radian (152x).

A dim pair that come with their own special silver lining. (East & west reversed, click on the sketch for a much better view).

Again, a dim pair, and not particularly hard to separate at 152x, but it has the merit of being at the center of an interesting field of stars.  In the south quadrant of the field, 9.2 magnitude SAO 21089 casts its yellow tinted light into the center of the black field, which is answered by a 10.1 and 10.2 magnitude pair of stars just to the north and northwest of SMA 2.  Both of those stars are inclined more strongly towards the southwest than the SMA 2 pair, providing a contrast in separation, position angle, and brightness.  If you visualize those two southwest leaning stars as the base of a triangle, the SMA 2 duo provides a punctuating double dot of light to what you might call a four-starred triangle.  Hey, there’s always a silver lining — you just have to learn to see it.

The initials SMA represent a rather interesting astronomer, William Marshall Smart.  Born in Scotland in 1899, he spent most of his astronomical career at Cambridge and the University of Glasgow, and wrote a book on positional astronomy (calculation of eclipses, transits, and occultations) that is still in use today, Textbook on Spherical Astronomy.  A full account of Smart’s career can be found here.

Near the northwest edge of the field is another double star, which proved to be a bit beyond reach of my light grasping six inch f/10 refractor, probably due to too much murk-like moisture in the air.  STI 1270 is composed of an 11.6 magnitude primary and a 12.9 magnitude secondary, separated by six arc seconds at a position angle of 95 degrees (WDS 1999).

In part two, we’ll look at three brighter and very diverse members of the Caph-ian family, so don’t touch that dial!  (or mouse, either).


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