|
I take it that you haven't done done photometry before.... How linear is the CCD for your target and comp stars for the exposure time you have chosen? Linearity falls off at both ends (over and under exposure) of most CCD camera's. Can I assume you used the 12"? 5 seconds in a 12" scope isn't going to produce a very high SNR for a magnitude 14 target meaning that whatever occultation you may record will be well inside the noise and linearity for such exposures is also questionable.
You have an option to stack your images (say 5-6 consecutive images) and then re-measure. Yes, your timing of the occultation will suffer but you should be able to get 0.05mag accuracy (or close to it) in the photometry and get around the extensive noise in your data.
(To achieve 2% photometry in my 14" I have to integrate for ~ 60 seconds on mag 14 minor planets)
|