Splitting Tools for Zeta (ζ) Lyra: Zeta yields to a 15X70 binocular hand held, or 8X40 binoculat mounted; 50mm scope splits it easily.
Finding and splitting these three wide pairs on a Summer or Fall evening should be a great way to get started with doubles – and if you’re already a veteran, they’re still worth a look. Veterans may find it more challenging to give them a try with binoculars – or that little, old 50mm refractor you bought on a whim!
Naming them is a bit more difficult for SHJ 282AC is listed in the Double Star Club (and elsewhere) as OΣ 525 and may be identified on your star charts simply as HIP92833. The Cambridge Double Star Atlas lists it both ways – OΣ 525/ SH 282. But this naming thing is a footnote – let’s get to the meat of the matter, how to find them.
First, these three are easy to find. All you have to do is locate one of the brightest stars in the sky – Vega. Then work from there. (Vega is the second brightest star in the northern hemisphere and about as close to magnitude zero as you can get. In Suummer and Fall it’s high overhead in the evening for northern hemisphere observers.)
As with most constellations, I have difficulty making a lyre out of the stars of Lyra, but I have no problem seeing two linked asterisms – a triangle and distinctive parallelogram.
I always find my way about Lyra in two steps. First I find Vega and the two stars that form a triangle with it. The northern most of these stars is the famous Double-Double. The other is our first target tonight, Zeta (ζ) Lyrae.
Zeta forms a bridge then to the rest of Lyra which is nicely marked by a parallelogram. Zeta marks the northwest corner and Beta (β) Lyrae (Sheliak), the southwest corner of this parallelogram. I always use Beta as a guide to finding the wonderful little Ring Nebula, M57. It’s about three-quarters of a degree to the east. If you’re familiar with it, you can use it as one corner of a triangle that consist of Beta, M57 and SHJ 282AC. If you don’t know – or can’t spot – M57, just go straight to SHJ 282AC. It’s little more than a degree northeast of Beta and at sixth magnitude considerably brighter than M57. (Hmmm…the shoe fits better on the other foot! If you’re looking for M57 then SHJ 282AC might actually be a help in finding it!)
These stars are all remarkably similar in the distance between them – about three quarters of a minute of arc. And Zeta and Beta are almost identical in position angle – so you can use Zeta to tell you where to look for the secondary to Beta and that should be a help since there’s five magnitudes difference in the Beta pair making the 8.6 magnitude secondary a little more difficult to spot in a small scope.
I, of course, used the 60mm Televue, my standard for the DSC-60 project. (For project details go here.)
John has already posted an excellent report on Zeta and Beta and you’ll find his write up here, so I won’t repeat all the details.
Zeta (ζ) Lyrae
Stats from the Double Star Club List:
|Zeta Lyrae||18h 44m.8||+37° 36′||4.3, 5.9||44″||150|
Haas lists the secondary a little brighter – 5.6. This pair is about 154 light years from us and has spectral classifications A, F0.
I found this split nicely using a 24mm Panoptic – 15X. I actually started with a 24 – 8 zoom, but really didn’t like the views I was getting. The 13mm Nagler gives a really solid feel at 28X and it was fun to crank it up a bit with a 5 mm Nagler – 72X. With that last I saw the colors of this pair as silver and violet. Lots of stars share the field of view, even at 72X, but none crowd it.
Don’t take my color report too seriously, however – people seem to be all over the map on the color of these stars. Haas reports a paid of “goldish white” stars and says Smyth saw them as “topaz, greenish,” while Webb saw “greenish white, and yellow.” John saw them as yellow and white in a 60mm – but saw both having a yellow tint when he switched to a 6-inch. Oh boy! Time to move on to Beta.
Here’s the DSC listing for Beta.
|Beta Lyrae||18h 50m.1||+33° 22′||3.4, 8.6||46″||149°|
And here’s John’s summary of facts:
Beta (β) Lyrae (Sheliak)
RA: 18h 50.1m Dec: +33° 22′
Mag: AB – 3.6, 6.7 AE: 3.6, 9.9 AF: 3.6, 9.9
Sep: AB – 46″ AE: 67″ AF: 85″
PA: AB – 150° AE: 317° AF: 19°
Distance: 881.5 Light Years
Spectral Classification for A & B: B7, A8
Notice that John includes a couple of other components. You don’t need to see these for the DSC, just the A-B components. But please note the large difference in reported magnitude between the DSC list and John’s numbers. John list these stars as 3.6 and 6.7 – which are the magnitudes found in Haas and in the Washington Double Star Catalog. I trust John’s sources and I can’t explain why the DSC list appears to be off – but I suggest you simply take it as a warning that the DSC numbers may not only be dated, but have some other errors in them. I include them because this is the official list for the Double Star Club certificate.
When I get looking for Beta in the scope I find it easy to confuse with the other southern corner star until I remember that one of these stars has several other bright stars in the field – and Beta is pretty much alone. I found the five magnitude range between primary and secondary made this a challenge at 15X, but a downright elegant sight at 28X. I saw the primary as white and – maybe this is a blessing – I could make out no color in the faint secondary. Haas has it as “sapphire” and Smyth – bless his colorful eyes – saw it as “pale grey.” Guess I could go with either of those descriptions, especially if I were using a larger scope – but in the 60mm I just am not ready to say.
Now color is the hallmark of our third easy double – in fact, Webb describes it as a “beautiful miniature” of Albireo – Beta Cygni. That comparison didn’t jump out at me, but I did see a pale orange primary and blue secondary.
The other hallmark here is the name. The DSC list identifies this as “Otto Struve 525.” Not really. OΣ 525 is the primary and the “B” component and thankfully the DSC is not asking you to split that – especially with a 60mm. That pair is 6.1 and 9.1 and just 1.8″ of arc apart! But look at the magnitudes in the DSC listing, as well as the generous separation of 45″ and it seems obvious they are talking about another pair – a pair both Haas and the Washington Double Star Catalog identify as SHJ 282AC.
Now honestly, I don’t understand enough about the nomenclature to know what’s most proper in this case. Seems to me it should be SHJ 282AC which gives the credit for this star to South, J. and Herschel, J. But OΣ 525 does refer to the same primary and Starry Nights Pro simply list it as HIP92833.
So if you’re going for the DSC certificate, you’re looking at OΣ 525, but that really means the easier of two pairs – technically the AC pair.
|Otto Struve 525||18h 54m.9||+33° 58′||6.0, 7.7||45″||350°|
This combination is a whopping 1,339 light years from us and the primary has a spectral classification of G8III. Notice that spectrum puts it on the orange side of yellow, so that fits my vision of a “pale orange primary” and also fits the comparison to Albireo where I always think of the primary as “gold.”
Can’t wait to give these three a shot with mounted 15X70 binoculars.