Hello,
I have difficulties with aperture photometry near the edges.
I have noticed that at less than 75 pixels (approximately), photometry becomes inapplicable (my outer radius = 31 pixels): is this due to incorrect handling on my part or is it a precautionary measure (which is not applied in VPHOT, I have checked).
I noticed this when trying to apply the aperture to an AAVSO comparison star near edge. Thank you.
If there is not enough space for the aperture circles, then photometry is not possible. This is normal.
Another reason why the star may not be taken into account is that it contains at least one pixel above the limit defined in the preferences (or below the lower limit).
If it is not the case, perhaps there is a bit too much protection against the edges.
As my signal is not saturated, far from it, I also assume that an internal limit has been applied.
In my example, this hypothetical distance limit is not necessary, moreover, VPHOT allows me to do this precisely on this star…
You can force it by making a selection around the star (big enough). Then right-click.
If you want to do it on the single image, choose PSF. If you want to apply it to the sequence, choose PSF for sequence.
Great! The handling is already working better, but unfortunately there is still a problem: I can’t get several stars to appear at the same time on the graph to retrieve the output data (.CSV):
If magnitude 1 is not displayed this is because magnitude 1 computation failed. It should be detailed in the console.
Also, you use registered data that have been interpolated. This is not recommended. It is better to use sequence where the registration is only computed in memory.
Yesss!
Console message :
“L’analyse photométrique a échoué pour l’image 66 (pas assez de fond de ciel)”
it’s good now. My selection green dotted line around the star was too small. Thanks a lot 
