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Comp or Check "Not Detected" ???

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B.P.Vietje's picture
Comp or Check "Not Detected" ???

I uploaded a 200-frame time series of a suspect variable (NSV 15146 at 00 41 39.76  +40 12 27.4), and thanks to the sequence team, was able to see the new Comp (95) and Check star (93) in the field to the east of the target.

Saved a sequence as usual, and attempted a time sereis.  Got an unusual message I've never encountered.  Both the comp and check stars were correctly identified, apertures correctly placed, and exposure is fine, but the check star (93) throws an error message:  "Not Detected"

HUH?  Color me confused.  Ideas?

Thank you and clear skies,


Brad Vietje, VBPA

Newbury, VT

MZK's picture


Can you run single image photometry? Is SNR low? Should be brighter than comp. Do Comps have all filter mags?

Share images to MZK?


B.P.Vietje's picture
"Not Detected"

Hi Ken,

Attached images might be most helpful.  ADU peak a bit low at around 8K, but SNR well over 100; 220 in the case of the "not detected" star.

New one for me.  Appreciate the help.

CTX's picture
NSV 15146 May Not Even Be Variable


While the followoing remarks have no bearing on your analysis problem I feel compelled to inform you of the following information RE this specific target (NSV 15146).

I did add these two comps, for a limited observer fov, as a favor to a student.... it is not a target that I would have observed myself.

The following information was received from a member of the VSX team who I had questioned regarding whether or not this target was actually showing any variability in advance of my adding those two comps..... you might have an interest in his remarks:

"This star was reported as having a 0.06 mag. dimming in 1979. More than 3 years of HIPPARCOS data did not show anything.

I can't rule out a long period eclipse but the amplitude is too small and the chances of catching (if it exists, which might not be the case) are very low."

Ad Astra,

Tim Crawford, Sequence Team



B.P.Vietje's picture
Thanks, Tim!

Well, as luck would have it, I'm attempting to help that very same student get some good data for analysis, so I've just learned the same about this target.

Sure thought the "not identified" message was pretty odd, though.

Thanks for helping with the field stars, even if this one was a bit of a wild goose chase.  Always something to be learned by trying something new.

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