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Double Trouble in Draco: Eta (η) Draconis, 26 Draconis, and Psi (ψ) Draconis

Draconian.

A word, an adjective actually, that generally indicates severity with respect to what it refers to — as in “draconian” punishment.  It derives from an ancient Athenian official by the name of Draco, who seems to have earned a permanent place in our language by prescribing severe punishment for minor infractions of Athenian law.

In other words, “Draconian” has nothing whatever to do with that long, winding, dragon-like constellation known as Draco.

Unless  ………..  you happen to encounter a certain pair of double stars.

One of them gets credit for transforming an enthusiastic, dedicated, die-hard double-star enthusiast into a distant-eyed zombie who for several weeks muttered incomprehensible and unintelligible sounds to no one in particular while staring in the general direction of Draco.  The only halfway intelligible sound I heard from him, repeated at intervals of 4.8 seconds, was:  “Eta bee, Eta bee, Eta bee . . . ”   ——   and 4.8″ just happens to be the separation of Eta “B” Draconis from Eta “A” Draconis.

And the other pair?  Well, it’s hard to know what to make of it  ………  since part of it isn’t there.

So consider yourself warned.

You are about to enter the Draconian Zone.  Restraint straps are mandatory.

Welcome, Earthling ….. you are in the Draconian Zone, where what is isn’t and what was wasn’t ……. a world entered only by the very brave …………… a world avoided only by the very intelligent. (Stellarium screen image with labels added — for a larger version, click carefully and stand back quickly).

And if you can survive the first two stops without developing an irrational fear of double stars — or the dark of night — the reward will be a real gem of multiple starlight at the last stop.

Buckle that strap.

And hang on.

Eta (η) Draconis can be found by starting at the distinctive rectangle formed by Beta (β), Gamma (γ), Xi (ξ), and Nu (ν). Draw a line from 2.2 magnitude Gamma (γ) Draconis to 4.9 magnitude Nu (ν) Draconis (better known as the Dragon’s Eyes), a distance of about five degrees, and then extend it twice that length to the northeast, and you’ll find Eta (η) beckoning to you. (Stellarium screen image, click for a larger version)

Eta (η ) Draconis   (OΣ 312)  (STT 312 in WDS)     HIP: 80331    SAO: 17074
RA: 16h 24.0m   Dec: +61° 31′
*****                   Magnitudes    Separation   Position Angle   WDS Data
AB:                         2.8,  8.2                 4.8″               139°                 1996
AB-C:                    2.8,   8.1            566.1″               240°                 1991
AD: (Bu 9008)     2.8, 14.3           110.9″                  87°                 2000
AF: (SMY 9002)   2.8, 11.5           363.7″                  18°                 2000
Distance: 88 Light Years
Spectral Classification: G8 (A only)

When I look at my observing notes on this one, all I see, repeated like a mantra of omission, is “no luck, no luck, no luck.”   The “no luck” is in reference to Eta “B” — the “C” and “F” companions  (seen in the sketch below) were a breeze by comparison, but of course “D” was a bit beyond my visual thresh-hold.

Now really, I knew this one would be difficult.  But even though the secondary is about 250 times fainter than the primary, I sure wouldn’t have called it impossible based on past experiences.  After all, I split Polaris all the time, and the magnitudes are 2.0 and 9.1, meaning the secondary is 627 times fainter than the primary.  Ahhhh …….. but then there’s the difference in separation — 18.2″ between Polaris “A” and “B” — versus 4.8″ for Eta “A” and “B”.

Which is always hard to account for.  But I should have known.

So I tried with my five inch Meade, I tried with my six inch Celestron, I tried with my six inch f/10 refractor — heck, I even tried with my eight inch Celestron SCT!  But nothing, nada, nichts  — as in null, as in no, as in not there.  I began muttering things in the dark.  And sometimes in the daylight.  “Eta “B”, Eta “B”, Eta “B”    ………….   every 4.8 seconds.

But I kept coming back, tugged at by an irrational obsession that had to be cured.  Of course, it didn’t help one bit that I thought I had seen it several times — but some people see ghosts, too.

Still, there was the color of that primary — a deep, rich, vibrant gold.  Really, it was worth the wait for the unlikely just to stare at Eta “A”‘s rich beauty sparkling in a jet black velvet sky.

So well past the point of expecting a sighting of the unseeable, I pointed an Astro-Tech 90mm f/6.7 refractor at Eta (η) — all I really wanted to do at that aperture was soak up some more of those luscious gold photons. And then, quite slowly actually, I realized I was looking right at what I hadn’t been able to see countless times before — a very, very miniscule point of white light parked very tightly against the edge of it’s much larger parent.

In an 8mm Radian, sitting in a 2x Barlow — 150x.

OK — it’s not like I wasn’t still looking for it.

“Eta “B”, Eta “B”, Eta “B” ……….. wait a second ……………. THERE IT IS! (East & west reversed to match refractor image, click for a version without this caption).

BUT I GOT IT!!!

Thinking back on the difficulty of the ordeal now, it seems I should have paid more attention to Haas’s description: “A brilliant lemon-yellow star almost touched by an elusive wisp of light.”  That was at 350x in a 125mm scope.

But it was that word — “elusive” — which somehow escaped me — elusively.

This is the strangest part of all, though: since catching sight of the elusive “B”, I’ve seen it in a four inch refractor and the six inch f/10 with very little problem at all.  The seeing HAS to be stable — at least a III — or you don’t have the first hint of a chance.  And your focus has to be very precise — very, very  precise — because that ghost-like wisp of light is on the shy side of shy.  And too much magnification only makes it more hopeless — you have to find the elusive middle magnification range.

The main thing — and seriously, I think this is a key ingredient in improving anyone’s observing skills — is that you have to be persistent, to the point even of being dangerously obsessed.  You have to keep looking, keep staring, keep coming back.  And the most surprising thing of all is once you’ve succeeded, the next time you look, it’s rare that your object doesn’t pop right into view with no struggle at all.

Makes you wonder how you ever missed it to start with.

Anyway  …………  make sure that restraint strap is still tight.  We’re going to move deeper into the Draconian Zone now.  Have no fear — I can get us out of here quickly.  I’ve been here several times before and I’ve always made it back.

……………….    At least so far.

You can follow the mysterious and unpredictable dark path to 26 Draconis by first leaping from Eta (η) to Zeta (ζ). Then extend a line southwest to Xi (ξ), and if you look closely on a dark moonless night, you’ll spy 26 Draconis at the halfway point. Or, take a peek in an 8×50 finder, and you should find a glowing gold dot of light beaming back at you. (Stellarium screen image, labels added, click for a possibly hypnotizing view.)

26 Draconis            HIP: 86036    SAO: 17546
RA: 17h 35.0m   Dec: +61° 53′
*****                        Magnitudes    Separation  Position Angle   WDS Data
AB: (Bu 962)             5.3,   8.5               .72″                307°                 2013
AB-C: (LDS 2736)   5.3, 10.2          737.6″                161°                 1999
AB-D: (SDR 1)         5.3,  11.6            23.9″                252°                  2003
Distance: 46 Light Years
Spectral Classifications:  GO (for A), F8 (for C)
Status: AB is closing rapidly, orbital chart can be found here

OK, we’ve arrived.  And it’s not as bad as you thought it would be, right?

But permit me to to show you what attracted me to this place in the first place:

AB-C is a showcase pair.  Gould, 200mm: ‘A bright yellow star with a wide faint companion; at 200x the primary star shows a close companion that’s seen with difficulty.’ ”  (Sissy Haas, Double Stars for Small Telescopes, p. 71, 2006 Edition)

Not quite a showcase to be seen here, but the lovely unattended gold beauty of 26 Draconis is stunning nonetheless! (East & west reversed, click for a larger image).

Obviously something’s not right — as you can see in the sketch at the right, there’s no showcase shining here.

Now it’s not “AB”, aka Burnham 962, that we’re concerned with here — “the close companion seen with difficulty.”  With three magnitudes of difference separated by .72″, we’ll need seeing even steadier than the rock of Gibraltar to see it, and we’re not going to get it on the north coast of Oregon under a meandering jet stream.  So that’s not what’s missing from the sketch.

What’s missing is the other half of the showcase pair.  In her book, Haas lists that missing half as “C” — as in “AB-C”  — and assigns it a magnitude of 8.1, a separation of 25.1″, and a PA of 241 degrees.  And that 8.1 magnitude star is nowhere to be seen in the sketch.

This image has been rotated to more closely match the sketch above. “C” is clearly shown here, and the faint star just to the west of the primary identified with the question marks may be our missing star. (STScI photo, click for a larger view).

But hold on to your spinning head!  As you can see above, the WDS (Washington Double Star Catalog) shows “C” to be a 10.2 magnitude star separated by 737.6″ (about 12.5 arcminutes) from “AB” at a PA of 161 degrees — and that star can be seen easily enough in the sketch above or the STScI photo shown at the left.

Now notice, if you will, that the WDS data above includes an “AB-D” pair, with “D” located 23.9″ from the primary at a position angle of 252 degrees — both very close to Haas’s data — and a magnitude of 11.6.  So at a minimum, it appears that the data for  “C” and “D” inadvertently got swapped around in the Haas book.  But what about the 8.1 magnitude Haas assigns to the “showcase” star?   And who in the heck does SDR refer to?  Where in the world of perplexing photons  is  “D”, anyway?

Well, if you look at the STScI photo, there is a very faint star — about 12th or 13th magnitude — just a bit west of the 240 to 245 degree position, which I’ve identified with question marks.  I’ve dragged the internet for some source of illumination and come up with an empty net, except for a discussion on Cloudy Nights that pretty much reached all the same conclusions I did.

However — one very handy source of information is the discovery dates of stars listed in the WDS catalog data, and in this case it does shed a few photons on the situation.  Bu 962, the “AB” pair, was discovered in 1879; LDS 2736, the “AB-C” pair was discovered in 1898; and our mystery star, SDR-1 — the “AB-D” pair — was discovered in  …………..  1996!   It all could just be a series of mistakes, but it really looks as though there is a basis for some kind of recorded observation having been made here.   Someone saw something at some point — apparently in 1996.

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

STScI photo, plots down in Vizier, click for a larger view.

STScI photo, plots down in Vizier, click for a larger view.

UPDATE:  When I wrote this post back in September of 2011, there was no magnitude listed in the WDS for the “D” component, and the most recent date for it at that time was from 1999.   Thanks to an email from Peter Morris, I was made aware that the WDS data now includes a magnitude of 11.60 for “D”, as well as an updated position angle of 252°, no change in the separation — and those figures are as of 2003.  All of which have been included now in the data line for 26 Draconis, as well as in the information in the text above.   Since September of 2011, I’ve found it’s possible to plot position angles and separations for individual stars using software made available in Vizier.  I’ve done that now, and the photo is shown here at the right.  There’s no date shown for the STScI photo, but it appears to be prior to 1999.   Both of the arrows in the photo are drawn to match the 23.90″ separation listed in the WDS for the “D” component.  I drew the lower arrow of the two out to the star that proved to be “D”, which the software plotted at a position angle of 232°.  The second arrow is drawn to match the 252° PA now listed in the WDS as being current for 2003.  SO — we now know where “D” is — apparently — and when I get a chance, there’s nothing better I would love to do than go back to 26 Draconis with more magnification to confirm it as well as to see if “D” has continued to move north.

And now, back to where we were before I interrupted the flow:

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

But ………  on the other hand  ……….  you may have noticed that 5.3 magnitude “AB” shines with a very deep gold color, a gold very much like that of Eta “A”, although a bit paler because of its dimmer magnitude  —-  so once again, this wasn’t a total loss.  I’m afraid I’ve spent so much time in the depths of the Draconian Zone that I’ve become addicted to the mellow tones of that rich gold — it illuminates the pitch black sky like a gleaming jewel inlaid on black satin.  But it’s the high pitched, quivering tones of the Twilight Zone Theme as it floats hauntingly out of the Draconian darkness that really sets my Star Splitter cap spinning.  😉

So let’s not linger any longer.  We need to get out of here.  Warp speed, Mr. Sulu!  Set course for Psi (ψ) Draconis!

To start your escape from 26 Draconis, leap backwards in time to Zeta (ζ), then quickly turn to the northwest and spring forward four degrees to reach Psi (ψ). You’ll see it at the northeast corner of a triangle formed by Chi (χ), Psi (ψ), and Phi (φ) — but don’t confuse those last two with Sci Fi (or ψ φ), as in Science Fiction.   (Altered once again from an original Stellarium screen image, click to see the chart without the caption).

Psi (ψ) Draconis   (Σ 2241)  (H IV 7 — AB only)          HIP: 86614    SAO: 8890
RA: 17h 41.9m   Dec: +72° 09′
Magnitudes   AB: 4.6, 5.6      AC: 4.6, 11.3      AD: 4.6, 12.7
Separation    AB: 15.3″          AC: 79.2″             AD: 105.7″
Position Angle    AB: 69°  (WDS 2012)   AC: 108°  (WDS 1999)    AD: 67°   (WDS 1999)
Distance: 72 Light Years
Stellar Classifications   A, C, and D: F5      B: F8
Status:  AB is physical, orbital chart can be seen here

Ahhhhhhhhhhhh ……….. the simple, uncomplicated beauty of a straight forward quadruple star — without multiple designations and no devious surprises.

Loosen that restraining strap, sit back, and just soak up the pure beauty of all this starlight — we’re in a friendly sector of the galaxy now.

When this unique little gem landed in my field of view, I could feel my eyes exhale a Psi (ψ) of relief.  No searching, no straining — it’s all right there in front of you, and easily taken in with a single glance in apertures of four inches or more.

The well balanced gold beauty of an uncomplicated quadruple star — a sight for sore eyes already well exhausted by seaching for elusive companions. (East & west reversed, click for a better balanced version without this caption).

And we’re back to gold once again, too — which certainly seems to be a Draconian characteristic.  For another taste of Draco gold, you might want to take a look at nearby Epsilon (ε) sometime, located four degrees to the west of Psi (ψ).

Now this is a paler version of gold than what I saw in Eta (η) Draconis — a more accurate description is gold with a distinctive pale white mixed into it — and I would call the color of the 5.6 magnitude secondary an imitation of that pale white.  Haas and I are close on color, at least on the primary — she describes both “A” and “B” as “lemony white.”  Admiral Smyth has them down as “pearly white” — and Haas quotes Webb with “whitish yellow, lilac.”  I have yet to see a lilac star, but it sure does seem a popular color for being so elusive.  But she has the description absolutely correct on this — a “showcase pair” it is, especially after the barren territories we’ve just fled.

The 11.1 and 12.6 magnitude “C” and “D” companions were obvious as a pair of dragon’s eyes in my six inch Celestron refractor, but I’ll leave their color to your imagination.  Although seeing those two in a 60mm scope takes a bit of effort, I could discern 11.1 magnitude “C” dancing dimly in a bright, moonlit sky — with averted vision — in my 60mm f13.3 Lafayette refractor.   What I really love about those two stars is their staggered positions south of the primary and secondary — discovering patterns like that is one of the joys of double star observing.  At any rate, the comforting, uncomplicated beauty of Psi (ψ) has earned it a place on my list of favorites.

Now wasn’t this fun?  Tempting fate in the dark tempestuous depths of the Draconian zone?  Of course, it’s always more fun when you get away unscathed — and we not only did, but were rewarded royally for our effort at the end of our escapade.  Adventuring every now and then into those unpredictable realms where the more intelligent among us have enough sense not to tread kind of spices up the old viewing experience.

But that’s enough of delving into Draco and dragons for a while — I fear I’ve been overcome by an irrational and irresistible urge to see what stellar lizards are like, so I’m off to get a closer look.  Follow me if you dare!

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11 Responses

  1. I, too, observed this quadruple this past Monday, not knowing it is more than a binary. The Lit. on the Astro League Double Star Club List doesn’t include the other two. I get them as both “brownish/white.” I got a theta of 19º and rho of 28.5″. I included 8 field stars in my sketch at 90X with my Plossl 26mm, OTA: C925. Again, I’d like to post my sketch.

    • Hmmm , , , Sorry, but I don’t see any way to post a graphic in a Word Press comment – but I’ll explore it.

      • OK – there is a work around. If you post your image somewhere else – on one of the free photo sites, or on Facebook, or some other site you have access to you, you can put the URL in your comment. The Url you put in a comment is clickable and will take a person to the image. If you go this route, I strongly suggest you copy and past the URL – one typo and it won’t work, so copy and paste is much safer. Hope this help. it would be nice to see your drawings.

  2. OK, here’s the link to my FB page with the sketch loaded as a Wall Photo: http://www.facebook.com/profile.php?id=630628441 (Steve – I’m taking the liberty here of adding the direct link to the image as it took me a while to find it – hope you don’t mind – https://www.facebook.com/photo.php?fbid=10150340305038442&set=a.104157458441.91029.630628441&type=1&theater
    Greg)

  3. Wow! Cool. That’s right off the Wall Photos page, right? Anyway, there it is. Hope you like it. That’s what I say through my C925 w/ my Plossl 26mm @ 90X…

    • Thanks, Steve – a sketch is always helpful – and it’s just simply fun to see how others see these stars. Now I have to go find my notes on Psi Draconis 😉

      • It looks a little to me like the two stars to the close in to the east are the “C” and “D” companions. The P.A.’s and Sep.’s seem to match, although I didn’t calibrate them at the time. If I get a chance soon, I’ll have another look at this system and report back…
        Thanks again for the help posting the sketch.

    • Nice sketch, Steve! Glad we could get access to it in the Comments section. I noticed your directions are opposite of mine – they’re oriented the same way the image would be in a reflector. Are you viewing through the SCT without a diagonal? That would account for it, at any rate.

      Anyway, keep the sketches coming – they’re always welcome!

      John

  4. John, I’m drawing ’em “like I see ’em.” I “sleep” the scope; let everything drift east – incoming stars are from the east. Then I slew north and incoming stars are north. Then I mark N & E on the log’s ocular circle and start plotting. I do use a diagonal in most cases…

    • Actually, in this case I may not have used my diagonal as it is pretty low to the northern horizon at that time in the morning. I’ll make a note on my logs from here on to make it clear to the viewer.

  5. I was able to just get a hairline split of Psi Draconis with the 10Z0 IS Canons – Darn they’re good! I couldn’t split the same pair with the 15X70 Celestrons on a stable parallelogram mount.

    Now seeing was sloppy and clouds were coming in and maybe the i difference in aperture made things worse, but I just haven’t seen these kinds of pinpoint stars in other binos – the kind I’m getting with the IS Canon’s – that image stabilization really makes a difference.

    It remarkably subtle. One moment you have a star dancing around and then, almost like watching a print develop in a tray, you realize you’re seeing two perfect stars.

    What’s fun with Draco and the binos is you can go on a neat progression from 16/17 at 90 seconds, to Nu at 60 Seconds, to Psi at 30 seconds – and all with stars that are pretty close to one another in magnitude.

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