American Association of Variable Star Observers (AAVSO)
Sun, 05/09/2021 - 10:47


I am following V1405 Cas nova and performing V and Ir measurement of it (note that I am still a newbie in this field). The last days the nova has brighten significantly and it is now difficult to find comp stars with good SNR. While I tend to get an SNR of 400+ on the nova, the comp stars have an SNR ranging within 20-60 (for Ir I had last night only 20 in SNR for comp stars).


Any suggestions on what to do here to improve my measurements?

Should I stack a few frames?

Currently, exposures for V and Ir are within 1 to 2 sek, thus I am not sure if stacking will help that much. What is the lowest SNR one should accept for comp star (e.g. if I only have 15 in SNR, should I even bother to register it)?

Thanks in advance.


American Association of Variable Star Observers (AAVSO)
Stacking will help with…

Stacking will help with bright stars in situations like this when no bright comp stars can be found in the FOV. If you stack enough images that the total exposure tuime will be like the exposure time you used when the nava was fainter, the comp stars will also have the same SNR as before (well almost, there is noise added by the camera each time you take a frame, so add some extra exposure time).