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A few Ursa Major doubles

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#1 John Fitzgerald

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Posted 30 May 2020 - 11:35 AM

Last night was a good session with my 6" f/8 triplet.  As usual, I used my 7mm Delite for 173x.  The seeing was somewhat better than it has been the last few months, probably 5 to 6 on the Pickering scale, with moments of 7.

 

STF 1770 m 6.9,8.2 sep 1.8" at PA 128.  This is a very nice double to observe.  Thought to be a binary.

 

STF 1795 m 6.9,9.8 sep 7.9" at PA 3.  The companion looks fainter than stated, at least to me. Uncertain binary.

 

STF 1830 m 9.3,10.3, sep 10.6" at PA 312.  1830 is components e,f, of this system which includes STF 1831 m 7.2, 9.6 sep 5.8" at PA 138.  There is another star, about mag 7, in between these two pairs, which are separated by 138".  I did not observe the 12th and 13th mag components of this seven star system due to bright moonlight relatively nearby.  The STF 1830 pair is optical, the close pair (STF 1831) is an uncertain binary, as are c,d.  The two brighter stars are presumed a physical, though widely separated, connection.


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#2 nerich

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Posted 30 May 2020 - 01:03 PM

Nice! Thanks John. STF 1830/1831 and 1795 have been duly added to my observing list. I had previously added 1770, upon reading the Admiral's enticing description: 

"A close double star, toward the tip of the Bear's tail. A 6, topaz yellow; B 8, livid (...) This exquisite object is one of Σ's "aureae vicinae," being No. 1770 of the Great Dorpat Catalogue."

Between his report and yours, I now have two hearty recommendations for this pair. Maybe, just maybe, it will happen tonight! 

I'm not the best judge of magnitude, but I'll let you what I see with the B component of STF 1795. 


Edited by nerich, 30 May 2020 - 01:03 PM.

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#3 chrysalis

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Posted 30 May 2020 - 01:40 PM

Per Webb:

 

STF 1770.JPG


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#4 John Fitzgerald

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Posted 30 May 2020 - 08:37 PM

I'm getting ready to head out to the little dome again.  Maybe I'll have more double star content in the morning.....


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