Cone and Christmas Tree Nebulae - Kelling Heath OSC

[Carole]

I grabbed this at the end of a very long night which was amazingly clear until dawn.  Therefore only managed one hour on this object by the time it rose.  This is about my 4th attempt to get this, previous attempts have been in Ha from home and too embarrassing to post.  I think this is one really difficult target, but maybe more subs another time might help.

Skywatcher ED120
QHY8L
5 x 600secs captured in APT

[MarkS]

This is a really tough target for full colour astro-photography - I haven't managed to get a result I'm happy with, even on the Tak under my reasonably good sky.  However, H-alpha tends to come out well from a dark place so I think a mixture of H-alpha and full colour is probably the key to getting a good result.

[Carole]

That's what I thought Mark.  I have tried it from home with an Ha filter but the results have been very poor. 

So if Ha is supposed to work in LP location but you say

H-alpha tends to come out well from a dark place

I am a bit confused.  So does this mean Ha doesn't work so well in a LP location?

Carole

[RobertM]

Carole,

No filter works as well in a LP environment !!!  The difference is that the narrower the pass band the more of the crud gets cut out.  If you want good Ha in a heavily LP area then in order of increasing signal to noise you have 30nm, 12nm, 7nm, 5nm, 3nm - unfortunately that is also in order of increasing cost .  I've tried 30nm, 12nm, 8nm and I'm currently on 5nm.

Robert

[Carole]

Thanks Robert, that is what I have deduced.
I have a clearer understanding now.

My filter is 7.5nm Baader (or thereabouts).  

Carole