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Q Cyg 126 comp star variable?

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lmk's picture
Q Cyg 126 comp star variable?

While estimating Q Cyg a short time ago, I noticed the 126 comp unusually bright, around 12.0-12.2? There were no other comps in this range on my chart to allow a good estimate. Could someone check please?






Will get the sequence team working on it.




FRF's picture
I have made several DSLR

I have made several DSLR images of the SS Cyg field in the past few years during my "Vendégcsillag-kereső" (Gues Star Hunter) programme. I think the 'comp 126' of Q Cyg is also visible on most of my images. I'll check it later.


Clear skies,


FRF's picture
Btw. Vend4 lies only ~20'

Btw. Vend4 lies only ~20' from SS Cyg. A nice SR variable, good target for visual observers too.

lmk's picture
12 comp star needed

Could someone on the chart team, add a few comps in the 11.5 - 12 range, to assist with this issue? I'd lke to try check the 126 again this evening, weather permitting. (I'll do a CHET also).




lmk's picture
126 is brighter

Thanks for the quick response by the chart team! I checked the 126 comp just now, and it was similar to last night. Using the new 120 and 124 comps, I estimate the 126 is 12.25 +/-0.1 So, this raises some questions:

1. Is this star actually brighter now than when the photometry was taken (I assume it was APASS?)

2. It somehow stands out more to me than earlier. I have observed Q Cyg many times, and only yesterday noted 126 being unusually bright. But, this is only a subjective assessment, I never actually estimated it!

3. If it is not variable, then there is some kind of photometric error, or some peculiarity of spectrum to make it appear 0.3 brighter visually than 12.569V.

I hope some others can take a look at this 126. Thanks,



Sebastian Otero
Sebastian Otero's picture
Previous observations

Hi Mike,

There is no evidence of variability in NSVS data. APASS gives V= 12.48, somewhat brighter than the 12.57 from Henden photometry that is used for the sequence data, but I've seen that usually APASS is some hundreds of a magnitude brighter so I'd trust the Henden value which is consistent with the transformed values from UCAC3 and CMC15 (12.57 and 12.55).

It looks like if this star is variable, this is something new. This may also explain why you found it unusually bright, this suggests you used int in the past without noticing any discrepance.

It would be very interesting if someone could make standard V observations right now!


dks's picture
Q Cyg 126 comp star observation

I've been doing photometry of Q Cyg for the last ~3 years, using 126 as the comp star. I dug through my old photometry (61 nights' worth) and don't see any obvious variation in this star relative to other comps in the field. My last photometry of this field was on 2016-01-04/5 and the 126 star was at a normal brightness relative to other comps at that time. Using the other comps stars its AAVSO magnitude value of 12.569 appears to be pretty accurate. This in no way rules out variability, though, since 61 short observation runs over three years is a microscopic sample!

Shawn Dvorak (Orlando, Florida) 

lmk's picture
126 is somewhat variable

I just observed it again this evening at 0600UT and it was noticeable fainter, more in line with its "usual" brightness. I estimated 12.45 based on the new 120 and 124 comps. Therefore, I only saw at brighter, around 12.25 for two nights, Jan 8 and 9 around this same UT. It is rapidly dropping down into the trees for me at my latitude, so can't followup much longer this season.

I think we need to add this star to the AID, please?



wstein's picture
126 does not appear variable

Observed this star with V filter on 9 Jan 2016 (JD397.563).  Nine images gave a V magnitude of 12.588 +/- 0.009. 

W. Stein (SWIL)

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