An attempt at bi-colour narrowband imaging - the Helix in HOO. Or should I say the Hoolix then?!
Perhaps not!
5.7 hours of Ha and 3 hours of OIII with an RC8 and ASI1600MM-C.
Because of weird issues with mixing data from 2 sessions (as per this
thread) though the brighter part of the nebula has nearly 6 hours of Ha, the rest of the image (i.e. the "eyebrow" etc) is just 3 hours.
Ha and HOO images attached and in full res on Astrobin
here and
here respectively.
Paul