Double stars in nearby clusters

[Size9Hex]

With Cassiopeia circling low in the north and pulling the Milky Way along behind it, it should be galaxy season. However, the waxing moon, although less than half lit, was high in the sky and casting shadows across the yard. Beautiful skies though, with the deep midnight blue of a clear moonlit sky beating the sad grey and orange dome towards town.

Hydra’s head poked above the rooftops to the south, catching my eye as a charming sparkle of stars in averted vision. Rising up into Cancer, barely visible in the moonlight. An unpromising start with...

• Delta Cancri: The faint companion invisible in the moon’s glare.

An excellent latching-on point point though, from which to begin star hopping into the Beehive Cluster...

• South 571: Easy split of identical white pair. Brighter third in a pleasing triangle.
• STF 1254: Off piste (from the Sissy Haas list). Lovely uneven pair.
• 39 Cnc: Very wide with 40 Cnc. Better in binos? Scope showed a nice yellow/white contrast though.

Leaving the cluster to stop at...

• 31 Cnc: Bright warm yellow with a splendid faint distant companion. 8mm.

...on the way to the unmissable...

• Tegmine: Spectacular! Bright yellow, close, slightly uneven double at 24mm. Primary elongated at 8mm and pinched waist becomes clear with barlow.

Over into the Coma Berenices cluster. Like the Beehive, this cluster is close to us - just a few hundred light years rather than a few thousand for the Messier clusters that lead them across the sky in the Milky Way. Sparkly star fields that overflow the eyepiece!

• STF 1633: Fabulous pair of eyes peering back! 24mm
• 12 Com: Triple. Bright yellow primary A. Well separated from the pale grey/blue C but great contrast. 24mm. B appears in averted vision within the primary glare after adding a barlow to the mix. 8mm
• STF 1639: Very close white pair. Not quite even. Distant faint third. 8mm
• 17 Com: Better in binos? Very wide slightly uneven pair 24mm.

Finishing with an outlier beyond the cluster...

• STF 1615: Easy uneven pair 24mm. Warm and cold contrasting colours. Mag 13 third member not seen. Bring out the dob!

I used a Baader zoom which I find to be very practical for casual sessions on double stars.

Take care everyone.

[Ciaran Meier]

Nice one.  Love the Beehive with the 15x70's. 

[Size9Hex]

6 minutes ago, Ciaran Meier said:

Nice one.  Love the Beehive with the 15x70's. 

I bet that’s a terrific view! Mine are 10x50s, but I often wondered about the view through a bigger pair. Do you mount yours?

[Ciaran Meier]

15 minutes ago, Size9Hex said:

I bet that’s a terrific view! Mine are 10x50s, but I often wondered about the view through a bigger pair. Do you mount yours?

Yep, bodged a DIY monopod from an extendable window cleaner and a retired camera mount. It ain't no manfrotto but it works a treat.  

The first time I had the 15x70's on the Beehive it just took my breath away.  I've an 8" newt but the view through this doesn't compare with the bins.  The bins are the Helios Stellar II from Flo, I'd say they're great value for money and probably not far optically from a set of Apollo. 

[Ciaran Meier]

4 hours ago, Size9Hex said:

South 571: Easy split of identical white pair. Brighter third in a pleasing triangle.

What catalogue is this from ? I'm using DSO planner and its not listed.  DSO planner has got all the main star catalogues and a few pretty obscure ones too.  South 571 looks like it's worth tracking  down. 

[Size9Hex]

1 hour ago, Ciaran Meier said:

What catalogue is this from ? I'm using DSO planner and its not listed.  DSO planner has got all the main star catalogues and a few pretty obscure ones too.  South 571 looks like it's worth tracking  down. 

I’ve never actually looked into the background of the catalog, but it seems to be this chap: https://en.wikipedia.org/wiki/James_South. The stars observed with (John) Herschel are denoted SHJ nnn, while those just from South himself are S nnn. The Cambridge double star atlas states that there are 118 SHJ doubles and 220 S doubles in the WDS catalog, so a little lower than the numbers stated on Wikipedia.

S 571 is also HD 73619, but it’s just one of many, many, many doubles up there. 😀  I’m following the Sissy Haas guide at the mo (hard to find now sadly), but if I wasn’t, there are some other great lists out there, e.g. http://users.compaqnet.be/doublestars/

 

[Ciaran Meier]

Cheers. Got it. Searched S571 (tried South 571 earlier) and up it popped from the Bright DS catalogue. It's listed in the WDS catalogue too. 

Checked it on the star map and turns out it's one I've noted before. It really stands out lovely in the big bins.  Tempted ?😉

Ciaran. 

 

  

[Size9Hex]

Ha ha, always tempted! 😀 Time and money though...! Maybe at some point in the future.

[F15Rules]

On 01/04/2020 at 14:55, Size9Hex said:

used a Baader zoom which I find to be very practical for casual sessions on double stars.

Nice report👍😊.

What scope were you using?

Dave

[Size9Hex]

14 hours ago, F15Rules said:

Nice report👍😊.

What scope were you using?

Dave

Thanks Dave. It’s a 5" f7.8 ED doublet from Altair which is somewhat new and I think I’m still getting used to. It’s the first large frac I’ve owned. I’d sure love to compare the view to an FS128 one day! That looks like a dream scope. 👍

[wookie1965]

Reading this did you get the third component of Tegmine I have tried quite a few times with my Tal 100rs and my 5" Meade but failed. 

[Size9Hex]

1 hour ago, wookie1965 said:

Reading this did you get the third component of Tegmine I have tried quite a few times with my Tal 100rs and my 5" Meade but failed. 

Yep. I’ve caught it a small handful of times in the 10" dob and this was the first attempt (and success) in the 5" frac. I thought it had a pinched waist rather than fully clean split. High power was needed. With the barlow, I was at 275x. Seeing conditions were good but not exceptionally so. Keep at it - I’ll bet you could get it in good seeing with either of those scopes, although perhaps as elongated/pinched rather than cleanly split. Good luck!