APT (Astro Photography Tool) is described as 'APT stands for "AstroPhotography Tool" and it is like Swiss army knife for your astro imaging sessions. No matter what you are imaging with - Canon EOS, Nikon, CCD or CMOS astro camera, APT has the right tool for planning, collimating, aligning, focusing, framing' and is an app in the education & reference category. There are more than 10 alternatives to APT (Astro Photography Tool) for Windows, Mac, Linux, iPhone and Raspberry Pi. The best APT (Astro Photography Tool) alternative is N.I.N.A., which is both free and Open Source. Other great apps like APT (Astro Photography Tool) are SharpCap, Nebulosity, Sequence Generator Pro and BackyardEOS.