M81 LRGB 10x180s

Hi Jerry, I assume it was done with a refractor but could you please tell me the aperture?

It was a Skywatcher Maksutov-Newtonian 190mm f/5.

The LRGB filters were exposed for 10 x 3 mins each.

The QHY23 was cooled to -20 degrees.

The RGB were binned 2x2 and then upscaled to match the L which was 1x1.

Aligned and stacked in ImagesPlus, with colour combination and processing in PS CS.

Ah, ok, thank you.