Re: Is "customized aperture" a candidate for AstroImageJ V5?

Posted by karenacollins on Dec 14, 2021; 5:28am
URL: http://astroimagej.170.s1.nabble.com/Is-customized-aperture-a-candidate-for-AstroImageJ-V5-tp1701p1704.html

Different aperture sizes within an image will not be implemented in v5, at least initially. From my perspective, this capability might be useful in certain circumstances, but for time-series photometry, better results will be obtained using stars of similar brightness, so apertures of the same size should be nearly ideal for most cases. We'll have to weight the additional complexity in the user interface (and in the code) to support multiple aperture sizes per image. We will most likely introduce the capability to have multiple apertures sizes for a single photometry run. Then the user (or an automated algorithm) can select the best overall aperture size. Unless your images have large distortions from center to the edges, measuring FWHM of different stars in the image will give a similar FWHM value. You can test this by alt-clicking on a star to draw the radial profile and read off FWHM. High contrast display of images will cause fainter stars to aperture to be "smaller" than brighter stars, but the FWHM will measure about the same, at least until the sky background starts to dominate the signal from the star.

Karen