We recently did Gum 15 in H-alpha and OIII, and confirmed that one night with a 20 inch yielded no detectable OIII.
But excellent images by Lee Borsboom, Geoff Smith, Paul Haese, and ESO show that there is lots of beautiful blue reflection nebulosity.
The
ESO shot is curious in that it seems to show too much green in the nebulosity. Never thought we'd hear ourselves saying that. But otherwise, we aimed to produce a similar effect to the ESO shot.
Herewith 17 hours total exposure over three nights, peering between clouds.
Big one here
FLI PL16803 on 20 inch PlaneWave. Lum 2hrs, RGB 5 hrs each, in 30 min subs. All scope and observatory control software, firmware, electronics, and processing software designed built written in house by us. Nothing purchased pre-cooked at the restaurant.
For those who've not had a go at it, this nebula is ridiculously faint. It takes a lot of exposure to get the noise down.
It looks as if the blue reflection nebulosity is in a different plane to (and seemingly in front of) the red emission nebulosity.
Doing natural colour has also brought out quite a pretty star field, with some hot blue cluster stars, a few lovely red giants, and the distant field of cooler redder Milky Way background stars.
Cheers,
MnT