Sorry I may not have been clear. I have two Canon 20D cameras, one standard and the one I am offering for sale which is modded for Astro use. So i didn't mix them up i put a small letter A on the bottom of the modded one.
Some years ago Canon sold a factory modded version of their 20D model branded 20Da. I just didn't wanted anyone interested in the camera to think it was a canon factory modded version.
I have been using this camera with a Ha filter which worked well.