Aperture Photometry Tool

Image overlays, graphical representations, statistics, models, options and controls for aperture-photometry calculations are brought together into a single package.

APT is executed on desktop and laptop computers, and is free of charge under a license that limits its use to astronomical research and education.

The software may be downloaded from its official website, and requires the Java Virtual Machine to be installed on the user's computer.

[1] A companion paper[2] compares the performance of APT vs. SExtractor,[3] an established command-line software program for aperture photometry.

APT also has pixel-zapping functionality, which can be used to temporarily set the value of select pixels to NaN (not a number), effectively removing them from the aperture-photometry calculations.

APT handles the commonly used tangent or gnomonic projection (TAN, TPV, and SIP subtypes), as well as the sine (a.k.a.

The wrapper script APT.csh can be executed from a terminal window to start APT running from any machine, including those with Linux-type or Unix-type operating systems.