Tugboat Doubles

[FenlandPaul]

Even though I’m no fan of feisty, sticky temperatures during the day, the opportunity to do some casual observing in shorts and flipflops brings a rare joy.  Popped out at about 8.30pm with the dob to have a scoot around some binaries in Lyra, armed with the Cambridge Double Star Atlas.  The sky was slightly hazy and so became increasingly milky as the near-full moon got higher.  Seeing was fairly good – Antoniadi II, occasionally III.

Beta Lyrae (Sheliak) was first up.  A lovely loose quadruple with the primary markedly brighter than the other components, which had position angles that I estimated (in order of brightness) at 180, 350 and 040.  All components seemed white to me.  In the same field, just to the south, was a rather lovely fainter pair than seemed to me light orange and a slightly dirty blue-white.  I couldn’t get any of these position angles to match up to the Cambridge DSA, so I might have been missing something here!

β648 (Lyra).  I couldn’t confirm the split of this one.  Primary is orange and there was a possible elongation westward but definitely not a clear split.

17 Lyrae.  White primary with a much fainter companion at PA estimated as 290.  What was really attractive about this pair was the way that the tiny companion seemed to tow the primary across the field of view.  I’ve decided to call these pairs “Tugboat Doubles”.

∑2474 and ∑2470 (Lyra).  This was the real treat of the evening and led to me emitting a gasp of delight.  In the same field of view were two similarly orientated, similar brightness pairs.  ∑2470 was the northernmost of the pair, with its white components with a PA of around 290.  ∑2474 was to the south and was more orange in colour, with a PA nearer 280.  For my money, this underdog double-double is a lovelier sight than Epsilon Lyrae.

Theta Lyrae.  Wide pair with an orange primary and companion at PA of around 105.

Eta Lyrae.  Brilliant white primary with a companion maybe 50” away and at PA of 130.  In the same field to the south west was a nice contrasty pair with a faintly orange primary and slightly blue-white secondary, which were slightly wider apart than Eta’s components.

Zeta Lyrae.  A lovely, wide white pair with a PA of around 160.

That’s the first doubles-only night I’ve had for some time and it was thoroughly enjoyable.  Estimating position angle through an undriven scope is fairly easy, with the stars drifting west (although don’t forget field orientation differs if you use a diagonal in a frac!).  At some point I need to do some field timings in different eyepieces with this scope so I can estimate separation as well. 

Thanks for reading!

Paul

[Stu]

 A nice evening Paul, a good way to make the most of the conditions. 2470/2474 are great aren't they? The Double Double's Double as I've heard it called

[cotterless45]

Brilliant ! Try Aries next time , some real thrillers there.

"Star splitters " in July 2015 , gives Sheliak from Aa down to EF. Also in the vicinity , HJ 1349 , Σ2407 and TAR3. All the main stars in Lyra are doubles except for γ.

17 Lyrae is a yellow and blue delight with a distant third star. Σ2474 and co. Are the better " other double double" , much easier and nicer agreed !

good hunting,

Nick.

[wookie1965]

Cannot wait go hunting doubles and triples when I get my Frac. 

[alan potts]

Very nice report as is the norm from yourself, the sky here is very milky as well, low down you cannot even see the mountains, never a good sign.

Alan.