I have seen this target on Astrobin and been wanting to do it for a while, but next door's tree was in the way. Having spent 2 nights imaging it I can see why it is not often done, must need very dark and copious skies.
It is still noisy, but don't really want to waste any more time on it particularly at this scale.
This nebula is just below M42, which is just off the picture top left corner, it shows on my larger ED72 Mono image.
Dual Rig, Ed80/Atik 460EX, ED72/Atik 460EX
HEQ5
SHO
Ha 5 hours (600secs)
Oiii 1h 10mins (4 x 300secs binned x2 & 5 x 600 binned x 2) No nebulosity showing in Oiii
Sii 1h 15mins (5 x 300 binned x 2 and 5 x 600 binned x 2)
Total imaging time, 7 hours 25mins.
(https://gallery.orpington-astronomy.org.uk/albums/userpics/10047/NGC1999_SHO_2_nights.png)
for your info, this is the larger version of the Ha only with a wider FOV showing the position of M42 in relation to NGC1999
(https://cdn.astrobin.com/thumbs/p-Pfl_X-ULql_2560x0_esdlMP5Y.png)
Lovely image Carole
Very Nice Carole.
Lovely Carole. Interesting to see in relation to M42