Seeking advice setting aperture photometry annuli...
Here is the problem.
As I understand matters, I should set the inner annulus (circle) to capture the light from the target star (Iris provides a "growth curve" tool to assist this), have a buffer to avoid close stars and set an outer annulus far enough away that it is not affected by light from the target or nearby stars. Then (ideally) I should use the same aperture settings for ALL measurements.
BD Pavonis presents me with a bit of dilemma. Referring to chart 12409GS, the problem is achieving the ideal aperture settings for the stars in the chart given as 12.6, 13.8 and 14.3 in particular.
The issue is finding a suitable common outer annulus.
Do you simply fit the outer annulus as best as the star field allows?
Or do you keep the inner measuring annulus the same and fit the outer annulus for each star idividually?
Thanks in advance.