Re-processed 3rd March 2018 - no luck so far getting any more data; I will try again when the moon goes away
.......
With my unmodified D5300 DSLR, the HII nebula Gum 15 is barely brighter than the surrounding diffuse red glow that surrounds it and it all sits way down in the noise.
I decided to share this small WIP version as I think it may be a while before I can get the data I need to impove it.
This one has way too much noise ( and hence quite heavy noise reduction / smoothing ) as the detail is very faint and I needed a massive stretch to pull it out - more data will help with that I think.
Seen small, from a very long way away, I don't think it is too bad
Gum 15 and Open Cluster CR197 in Vela
Unmodified Nikon D5300
Orion Optics CT12" Newtonian with ASA Coma Corrector ~ effective focal length 1400mm @ f 4.7
HDR image in 10 sets ( all at ISO 250 )
- 35 x 240 sec + 5 each for exposure durations from 0.5 to 120 seconds