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6 Struves in Boötes

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6 Struves in Boötes was created by flt158

Hello my double star friends. 

I was noticing I was going to have very clear skies on Wednesday night 15th June 2022. So I pumped myself up and decided to place my William Optics 158mm f/7 apochromatic refractor with its small WO 70mm f/6 apo attached. But I fully recognised that the double stars I had presented myself were seriously close to the zenith. Therefore I lengthened the tripod legs to a much higher position. This meant my focusing knobs wouldn’t collide with the Berlebach Planet alt-az mount. It worked!
You see, my doubles were all in northwest Boötes.
Sunset occurred at 21.54 Irish Summer Time.
There really was no wind; and the air temperature was 16˚ Celsius.
The first stars were refusing to appear with my unaided eyes until shortly before 11pm.
So not much time to split the following systems as I had promised to stop observing at midnight. Because of mirror diagonals my north is upper left and my east is upper right. Time to put the skates on! 

I have 6 Struve doubles for you all. Facts and figures are, as ever, from www.stelledoppie.it 

1. I starhopped from 1.9 mag Eta Ursae Majoris (Alkaid). Then straight up north to a rather famous double – double. The first, which was on the left, was Kappa Boӧtis. This double has the alternative designation STF 1821 and it is a true binary. Magnitudes: A = 4.5. B = 6.6. Sep = 13.8”. PA = 235˚. I was welcomed by the beauty of STF 1821. 

2. Immediately east (to the right) of Kappa Boo is Iota Boӧtis. It is otherwise called STFA 26 and is also a true binary. Magnitudes: A = 4.8. B = 7.4. Sep = 39”. PA =33˚. With my 28mm 2” eyepiece 40x it’s a wonderful sight to see these extraordinary binaries separated and placed side my side when they are so close to the zenith.

These next 4 systems I have never observed before. 

3. North of 4.2 mag Lambda Boӧtis is a dim optical double called STF 1826. Magnitudes: A = 8.9. B = 9.7. Sep = 4.5”. PA = 310˚. I was greatly surprised to notice that the 2 stars were trying to split at a mere 40x. Of course 112x did this double justice. I could see that the primary was F8 yellow-white, I also thought the secondary was slight blue. 

4. The A & B of STF 1843 is a true binary. C is optical. Magnitudes: A = 7.7. B = 9.2. C = 9.7. Sep’s = 19.8” and 100.8”. PA’s = 186˚ and 63˚, There was no hassle seeing all 3 stars separated at 40x of course. But I thought I should check out the colours as there are interesting. A is definitely F4 yellow-white and C is G5 yellow okay. According to Simbad B’s spectral class is F5. As I increased to 112x I thought it had a slight orange tinge rather than a simple yellow-white. If others decide to study STF 1843, please feel free to come back to me regarding its colours. Thank you!

5. STF 1834 is a true binary for sure. It has a Grade 3 orbit and is slowly widening year after year. Magnitudes: A = 8.1. B = 8.3. Sep = <1.65”. PA = <104˚. I was on tenterhooks as to what magnification I would need to separate STF 1834 although I knew I would win at some point. So the good news is I could see the 2 stars touching at 112x. But grand success was to be had at 140x. And what a beautiful sight it is! The primary is yellow-white the secondary is white. STF 1834 was the showpiece double of the night. 

6. Midnight was closing in on yours truly. I had one more faint double to seek out. STF 1806 is a true binary. Magnitudes: A = 10.1. B = 11. Sep = 13.1”. PA = 173˚. I had no problem separating this double at 40x – even though both stars were so faint. At 112x I noticed that the primary was F8 yellow-white. The secondary was white. 

There were other doubles in the same area; but I had great difficulty seeing the secondary of BU 715 which is very near STF 1834. So I decided on not chasing even more difficult ones. Maybe if the sky had been darker I would have had better success with BU 715.

However I was very pleased with my one hour observing session. 

Thank you for reading my report. 

Comments are, as always, very welcome. 

Clear skies from Aubrey.              
The following user(s) said Thank You: michael_murphy, Fermidox, Until_then-Goodnight!
1 week 3 days ago #111286

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Replied by Fermidox on topic 6 Struves in Boötes

Another super report Aubrey, and fair play to you for continuing to observe during these short summer nights.

Finbarr.
The following user(s) said Thank You: flt158, Until_then-Goodnight!
1 week 2 days ago #111288

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Replied by flt158 on topic 6 Struves in Boötes

Thank you very much, Finbarr. 
And a thank-you to you Michael also for your "like". 

One vintage double star aficionado with a 20cm reflector on Cloudy Nights has given me his colours regarding STF 1843: yellow and auburn. This seems remarkably close to yours truly.  

Clear skies from Aubrey. 
 
The following user(s) said Thank You: Fermidox, Until_then-Goodnight!
1 week 2 days ago #111289

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Replied by Until_then-Goodnight! on topic 6 Struves in Boötes

Hi Aubrey,

It seems from your excellent report you had a wonderful hour under the stars. With the Summer Solstice around the the corner it won't be too long before can give BU 715 a go. 

Clear skies,

Darren.
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1 week 1 day ago #111290

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Replied by flt158 on topic 6 Struves in Boötes

Hello everyone. 

I'm sorry I haven't replied until now. 
I've had a heavy cold. 
2 days of sneezing and a chesty cough. 
Thankfully a great medicine has begun to work. 

Darren: yes I would love to have another go at BU 715. 
But I wonder when that will occur. 
I definitely need darker skies. 
Maybe I will need to wait for next spring when this tough double will reappear in the eastern sky. 

Still STF 1834 was a magnificent find. I would recommend that binary to anyone!
I will have to wait for a little while before I'm well enough to set up Galileo  again.  

Clear skies to everyone from Aubrey. 
6 days 7 hours ago #111297

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Replied by Until_then-Goodnight! on topic 6 Struves in Boötes

Hi Aubrey, 

Sorry to read that you're feeling poorly, but hopefully you'll be back to full strength soon. 

Take care, 

Darren. 
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5 days 22 hours ago #111299

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