Quote:
Originally Posted by Bassnut
Interesting you say thet Peter, its still just Ha isnt it?. I have much less signal from the Helix than any other neb, whys that?. A prevoius attempt at 15nm was far more sucessefull, Im puzzled.
|
The ionized nitrogen line is also pretty close to the H-Alpha, and this would be transmitted by a broader filter.
Also with the Helix in urban skies, you are chasing a signal to noise ratio optimum. It's very low surface brightness is easily affected by skyglow and transparency. Any thin cloud would make it a very difficult target.