Zeta Herculis and other doubles

[Size9Hex]

The constellations really whizz past quickly in the spring as the evenings stay light for longer. Lyra, Cygnus and Ophiuchus already stepping up by the end of the evening. Beautiful and peaceful out there last night, and pleasantly warm for April. A small bat on manoeuvre above, silent except for a few clicks.

Started in late twilight with a quick look at the crescent Venus and then latched onto Polaris for a star hop across a still blue sky.

Super happy to split Zeta Herculis at the end of the evening. Have tried a number of times over the years without success!

[edit - After a reply below which prompted a closer look, I think I was mistaken with the Zeta Herculis split]

Notes below in reverse order - seems that’s how Sky Safari exports them!

Hercules

• Zeta Herculis - Tough! Bright yellow. Barlowed 8mm reveals a grey spec dancing intermittently just outside in the first diffraction ring.

Bootes

• STT 292 - Very wide. Small orange and smaller grey. 24mm.
• 49 Boo - Wide pair but great contrast. Warm yellow bright primary and smaller grey partner. 24mm.
• STT 298 - Wide seemingly dull pair. Primary is rod shaped at 8mm though and narrowly split with a barlow. Nice!
• Alkalurops - Brilliant! Wide but great contrast. Pale yellow and pale grey/blue. 24mm. At 8mm the grey companion splits into a tight slightly uneven pair too! Beautiful.
• STTA 137 - Wide uneven couple. 24mm.
• STF 1889 - Close rather uneven double in an attractive field of scattered wide pairs. 24mm.
• 39 Boo - A terrific pair of eyes. 8mm.
• BX Boo - Wide rather uneven colourless pair. 24mm.
• Asellus Secundus - Wide bright and uneven. Warm white and battleship grey. 24mm. Fab.
• Asellus Tertius - Splendid view with Secundus in 24mm. Bright uneven pair. Slightly warm yellow primary and grey companioon.
• STF 1812 - Closish uneven pair. 24mm. 8mm pulls out a wide very faint 3rd.
• STF 1850 - Charming wide white pair. Almost even and not too bright. 24mm
• Izar - Brilliant! Bright yellow primary and a splendid smaller close diamond companion. 8mm.
• STF 1785 - Very close almost even. 8mm. A hint of gold?
• STF 1793 - Smashing! Close but clean split at 24mm. Colourless and a little uneven.
• S 656 - Wide pair in a lovely kite/turtle asterism.
• 1 Boo - Wide bino double. Meh... but wait! 8mm plus barlow pulls a faint companion from the glare of the primary!
• Muphrid - Warm white to yellow bright primary and wide faint companion. 24mm.
• STF 1825 - Close uneven colourless pair. 8mm.

Ursa Minor

• HJ 2682 - Smashing uneven flattened isoceles triple. AB easy at 24mm. Faint C easier at 16mm.
• STF 1798 - Elegant close uneven colourless pair. Suspected at 24mm but obvious at 8mm.
• HJ 2733 - Bright warm yellow/orange primary. 8mm pulls out wide faint companion in AV.
• STF 1972 - Lovely wide bright slightly uneven double. Nice scattered field stars. 24mm.
• STF 2034 - Extremely close. Just split in barlowed 8mm. Almost even white pair.
• Polaris - In twilight. Yellow with a small companion. 24mm.

Failed on a couple too. STF 1816, STT 289 and STF 1909. Oh, and a cheeky detour to the brilliant granulated M3 while in Bootes.

Safe and happy Easter everyone. Hope others are finding the some peace and a feeling of normality at the eyepiece (or indeed in any way at all) at the moment too.

Edited April 13, 2020 by Size9Hex
Zeta Herculis, even tougher than I thought...

[John]

Very nice list there Paul and many congrats on Zeta Herc - a toughie !

 

[Size9Hex]

5 minutes ago, John said:

Very nice list there Paul and many congrats on Zeta Herc - a toughie !

 

Thank you John. I’ve taken a large amount of inspiration from you and your posts on this one for sure. 👍

[chiltonstar]

Good stuff Paul! What aperture scope are you using - I normally get the secondary of Zeta Her almost on the first diff ring, so presumably you are larger than my 'umble 180 mm??

Chris

[Stu]

Excellent stuff Paul, a very good haul there. Might have to Nick your list 👍👍

Well done on Zeta Herc. I’ve only managed it once, well twice if you count it through two different scopes on the same night; OO 8” f8 and Mewlon 210. It needed excellent seeing, I’ve tried and failed for years!

[Size9Hex]

11 hours ago, chiltonstar said:

Good stuff Paul! What aperture scope are you using - I normally get the secondary of Zeta Her almost on the first diff ring, so presumably you are larger than my 'umble 180 mm??

Chris

This is uncomfortable, but I’ve had to conclude I was mistaken in believing I’d seen it. It’s a 5" scope. After reading your comment, I’ve looked a bit more into how large the diffraction pattern would actually be in my scope, vs. the separation of this double, and it just doesn’t stack up with my observation. I thought there was an intermittent grey speck, consistently appearing in the same place. After making the observation, I confirmed it matched the position angle in Sky Safari (which I deliberately hadn’t checked beforehand). But, it was too far from the primary. I’m rather confused by what I saw, or at least thought I saw. Some effect from imperfect seeing or imperfect vision or even just wishful thinking maybe. I though I’d been careful with this observation (as I hope I am with all) before calling it. With doubles, I estimate the position angle and need to see it match within a small number of degrees, but I’m a bit less strict on the magnitude, separation and colour which I find harder to estimate well (but have to "look/feel right"). I also compare against the displayed view in Sky Safari. But this one got through. Feel pretty dumb. . Will have to go back to this one (yet again!) for another look!

[Stu]

1 hour ago, Size9Hex said:

This is uncomfortable, but I’ve had to conclude I was mistaken in believing I’d seen it. It’s a 5" scope. After reading your comment, I’ve looked a bit more into how large the diffraction pattern would actually be in my scope, vs. the separation of this double, and it just doesn’t stack up with my observation. I thought there was an intermittent grey speck, consistently appearing in the same place. After making the observation, I confirmed it matched the position angle in Sky Safari (which I deliberately hadn’t checked beforehand). But, it was too far from the primary. I’m rather confused by what I saw, or at least thought I saw. Some effect from imperfect seeing or imperfect vision or even just wishful thinking maybe. I though I’d been careful with this observation (as I hope I am with all) before calling it. With doubles, I estimate the position angle and need to see it match within a small number of degrees, but I’m a bit less strict on the magnitude, separation and colour which I find harder to estimate well (but have to "look/feel right"). I also compare against the displayed view in Sky Safari. But this one got through. Feel pretty dumb. . Will have to go back to this one (yet again!) for another look!

No need to feel dumb Paul. It was a diligently made observation and you’ve reassessed it subsequently and honestly which is what counts. I’m sure there are observations of tough doubles reported on here which may be mistaken but remain unquestioned.

I'm sure you will get it at some point, a lot is down to seeing conditions, as said I struggled years, the benefit of which was that I knew clearly when I did actually see it, and was able to repeat the observation the same night in a different scope.

[Size9Hex]

Thank you @Stu, kind words.

I’ve recorded the occasion below so I can look back and chuckle! 😀

[John]

This is a highly magnified sketch that I made of Zeta Hercules when I first managed to split it a few years back. This was with my ED120. The secondary star appeared as a greyish lump in the diffraction ring rather than a neat star. My 130mm refractor shows it a little more clearly split than this. When Hercules is higher the split will get a little easier to see:

 

[chiltonstar]

Certainly, with my 127 Mak - almost 5" (actually 119mm), it is visible on occasion, and shows up on an image when the seeing is excellent++, eg:-

Chris

 

 

[Size9Hex]

Thank you @John that’s a very helpful sketch and notes on where/what to look for. What I saw (or thought I saw) was less bright, and also further out from the primary.

As I think about it, although I’ve observed perhaps a few hundred double stars over the years, very few stand out as having had a primary with a diffraction pattern that interferes with a fainter secondary. There have been plenty that are very close/touching, but these were faint enough to not have visible diffraction patterns, or plenty of others with a visible diffraction pattern, but the secondary being far enough out to not be part of it - or bright enough to hold it’s own weight.

I wonder is there a knack/approach/method to these type of binaries.

[kerrylewis]

I’ve finally split my nemesis!

After a cracking evening chasing doubles through Virgo, the Ursas, Draco etc , I realised that seeing was very good having split a few close ones that have been a challenge before. So I decided to wait for Hercules to clear my unfavourite tree and give old Zeta a go. 
 
I ramped up the magnification using the Vixen HR 2.4mm (with the 100mm Tak) and after letting things settle down the star image was very steady with clear Airey disc rings. I was guided by John’s excellent sketch and there on the  first ring was the elongated grey blob in the right position!

I have tried before without success. I also erroneously thought I’d got it once in the past and even described it as ‘easy’ on this forum attracting scorn and derision!

So - a great feeling having cracked it at last but also some disappointment because it doesn’t actually look like a double does it?! Having viewed some crackers earlier on ranging from close matched bright pairs to those with faint companions, old Zeta just doesn’t compare as a spectacle. 

But  I did it - and a special thinks to @John without whom this may have not been possible 😀

 

 

[Size9Hex]

1 hour ago, kerrylewis said:

I’ve finally split my nemesis!

Nice one Kerry. Great to hear that you’ve split it. Sterling effort! Glad I’m not the only one to view it as a nemesis! For no good reason, it’s bugging me in a way that others (e.g. Sirius B ) aren’t. Thanks for your comment about a previous attempt on it too. It’s nice to hear of another similar experience on this.

[kerrylewis]

31 minutes ago, Size9Hex said:

Nice one Kerry. Great to hear that you’ve split it. Sterling effort! Glad I’m not the only one to view it as a nemesis! For no good reason, it’s bugging me in a way that others (e.g. Sirius B ) aren’t. Thanks for your comment about a previous attempt on it too. It’s nice to hear of another similar experience on this.

Hello Paul. 
I meant to refer to your experience in my post. I never satisfactorily explained to myself how I made that mistake - for all know I might have been looking at the wrong star! 😀