One method of searching for variable stars within a field, which is also useful in image magnitude calibration, is to generate a plot of magnitude error vs magnitude. When run with batch photometry of time series images, the variable stars show large error due to inconsistent relative magnitude, while the stablest stars may be selected as comparison stars and catalogue values can be used for absolute photometry. When run on a single image, the magnitude error can still be used, but then something like a check of VSX may need to be done before selecting comparison stars.
While considering how to implement magnitude calibration within Afterglow Access, it would be great if a means of generating such a plot and using it to identify variables when running batch photometry can be done. Such a tool would have interesting educational applications, but I think also would be very useful for magnitude calibration.
One method of searching for variable stars within a field, which is also useful in image magnitude calibration, is to generate a plot of magnitude error vs magnitude. When run with batch photometry of time series images, the variable stars show large error due to inconsistent relative magnitude, while the stablest stars may be selected as comparison stars and catalogue values can be used for absolute photometry. When run on a single image, the magnitude error can still be used, but then something like a check of VSX may need to be done before selecting comparison stars.
While considering how to implement magnitude calibration within Afterglow Access, it would be great if a means of generating such a plot and using it to identify variables when running batch photometry can be done. Such a tool would have interesting educational applications, but I think also would be very useful for magnitude calibration.