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STF 2631 in Sagitta

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#1 ssmith

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Posted 13 September 2019 - 04:52 PM

Photographed this one last night using my C9.25 and the colors were particularly vivid.

 

The primary is a G0 but I couldn't find the spectral properties for the secondary.

The color indexes for the components are +1.09 & +0.2.

 

These stars contrast nicely with the nearby orange star HD 345775 which has a color index of +1.47.

 

STF2631 Sge C9 9-12-19 mean 3fr.jpg

 


Edited by ssmith, 13 September 2019 - 05:13 PM.

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#2 John Fitzgerald

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Posted 13 September 2019 - 05:01 PM

STF 2631 in Sagitta:  I will plan to have a look next chance I get.


Edited by John Fitzgerald, 13 September 2019 - 05:20 PM.


#3 ssmith

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Posted 13 September 2019 - 05:15 PM

Thanks John - I had it labeled properly in my photo.  I corrected the title of the topic.



#4 Far Star

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Posted 14 September 2019 - 06:39 AM

Very nice photo!



#5 fred1871

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Posted 14 September 2019 - 07:40 AM

Fine image, as per usual from you, Steve...

 

The colour indexes, assuming you mean B-V, +1.09 is a fit for a spectral K-type star, +0.2 for type A, and +1.47 for M.

Interesting, if the spectrum of the +1.09 is listed as G0.

 

Could be some further investigation to do. smile.gif

Or my calibration listing is way off... frown.gif



#6 ssmith

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Posted 14 September 2019 - 10:20 AM

Fred - 

 

I went back and took a look at the Simbad reference for the special type.  They gave it a quality rating of “D” which is pretty poor (A through E with E being the poorest rating).  Also there wasn’t a bibliographic reference given.

 

I’d say it would be fair to assume that the spectral class could be way off.



#7 azure1961p

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Posted 15 September 2019 - 07:39 AM

Steve,

 

Great shot, love that blue.  As always I like the way you format your work.

 

Pete



#8 John Fitzgerald

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Posted 16 September 2019 - 10:18 AM

Last night I observed STF 2631.  Nice, easy, at 173x in my 152mm.

 

Also observed STF 2634, which, to me, was a very similar double, also looked yellow and blue.

 

Also, STF 2651, which is equal, both looked white or bluish white, and was seen at 304x.  Rather tight, and almost east and west orientation. WDS gives m8.4, 8.4, dist 0”.9.  PA 280.


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