Sharing my latest narrowband image of the Helix, taken with my trusty Mach1 controlled by SGP - set up in the afternoon, polar align at dusk and pack up in the morning. Easy-peasy.
Some basic info:
-> The image is a blend of 0.55 HA_SNO + 0.1 HA_HNO + 0.35 HA_HSO. I know, not really scientific.
-> Integration (203 hours):
HA = 194 x 900s + 157 x 1200s
OIII = 124 x 900s
NII = 88 x 900s
SII = 167 x 900s + 22 x 1200s
-> 4" refractor, ICX 814, coastal location 20deg South of the Equator.
-> The background looks a bit gritty, but the data is extremely stretched, since background st.dev in all masters was only about 1 ADU.
High resolution: https://cdn.astrobin....6_wmhqkGbg.jpg
Thank you for looking