"R. Kantrowitz" wrote in
:

You need about 200-225x and steady skies in a 4 inch apo. 150x is too
low. I've tried filters, they dim the image too much, as does very
high magnification. The companion does fall on the first diffraction
ring. Turn off the drive and watch the direction of drift. The
companion will appear as a small blue disk leading the primary. The
best nights are usually hazy, even slightly murky, with very steady
seeing. Antares should be nearly due south to get some altitude.

Some would say (I would say) green. g. I saw it last year in 8" SCT with
an off axis mask, and this year in a 6" Newt.