PDA

View Full Version here: : Rosette Neb HaRGB


RobF
26-07-2020, 04:37 PM
Found this in the archives from 2017, never processed. Think I'd been hoping to get SII and OIII at the time but summer imaging in Qld can be fickle between work, hols, crazy Christmas period. Anyhow, here is an HaRGB of a fav object of mine:

5hrs Ha (20 and 30min subs)
3hrs RGB (approx 1 hr each, 5 mins subs)
QHY9, FSQ106ED, dark skies.

Only regret is the flat fielding - not sure the old cal data I've used fitted properly, especially around the outside of the Ha field. Anyhow, here are Ha and HaRGB versions of the Rosette for your enjoymentt and critique. :)

multiweb
26-07-2020, 09:59 PM
Awesome set of images Rob. Outstanding details and great contrast and dynamic range. :thumbsup::thumbsup::thumbsup:

gregbradley
26-07-2020, 10:37 PM
Very very nice.

Greg.

strongmanmike
26-07-2020, 11:15 PM
Lookin good Rob, great find. The Rosette is such a great object to image huh? so many interesting bits to see.

Mike

RobF
27-07-2020, 08:57 PM
Thanks for checking it out guys.

One day I'll get in there and do some NB, but very happy with the colour and mono Ha for now :)

Placidus
27-07-2020, 09:56 PM
Lovely work. The close-up of the Ha shows fine detail. In the attached we tweaked the black point very carefully, removing sky glow (on a per-channel basis) but with no data loss.

RobF
28-07-2020, 06:44 PM
Thanks Mike and Trish - that does have lots more impact and can't see any loss of data. I'm probably bit too obsessive about keeping some noise and not dropping the background. Was being careful with the poor Ha flat-fielding, but didn't realise how high I'd let the background get.

Question - if you tweaked the black point on each channel, how did you keep the colour balance - any compensating gain "stretch" or were the tweaks so small it didn't affect overall colour?