Horsehead season; idea for controlling Alnitak

[ollypenrice]

Alnitak is, of course the bane of our lives in Horsey images so here's an idea that I'm going to try ASAP. The star grossly flares, bloats and tries to dominate the image so we want to keep it down.

The main componenet of Alnitak is an 09 spectral class blue supergiant. The nebulosity around it is Ha dominated, so red. How to get less Alnitak and more nebulosity? Use a red filter.

When I have my shortish red exposures all ready for the final image I intend to try to apply just the area around Alnitak to the luminance frame so it will be red-for-luminance just for the area around the star. (Paste red onto lum and then put a big feathered marquee around the bloated region, select inverse and run 100% erasor over the lot. Flatten image and away.)

I don't have any decent horsey data in LRGB to play with but if anyone thinks it's worth a try you can always give it a go.

Olly.