Help with HST Elephant please

[gnomus]

I am attempting my first narrowband image - I have chosen the Elephant's Trunk. I got lucky the other night and managed to capture 4 hours (12 x 20 mins) of Ha data. I have processed this quickly just to get a look-see, and am reasonably happy with this. My question is: what is the appropriate next step? I have looked on Astrobin and it seems to me that most people are capturing more Ha than OIII or SII. Some seem to capture their OIII and SII binned at 2x2.

I am using the Baader filters. My pixel scale is around 2.5 arcseconds per pixel. What would be a reasonable proportion of Ha/OIII/SII? Should I bin? I may try to get another couple of hours of Ha - does 6 hours of Ha seem a reasonable basis for an image?

Thanks in anticipation?

[swag72]

I personally try to aim for equal amounts of all three and never bin any of the data....... of course, this can become rather soul destroying at times and so I am prone to giving up!!!

I always capture the Ha first, so at the very least I can get a decent mono image and then also use that as a luminance channel. I reckon on about 8 hours per channel, but with my slower scope I'm going for 25x1800s. As I said though, this is academic and I tend to cut virtually all the corners that I can when I get bored

[gnomus]

I personally try to aim for equal amounts of all three and never bin any of the data....... of course, this can become rather soul destroying at times and so I am prone to giving up!!!

I always capture the Ha first, so at the very least I can get a decent mono image and then also use that as a luminance channel. I reckon on about 8 hours per channel, but with my slower scope I'm going for 25x1800s. As I said though, this is academic and I tend to cut virtually all the corners that I can when I get bored

Thanks Sara. I believe you use these 3nm Astrodon (hyperexpensive) jobbies. I am using the Baader 8.5nm filters. Would that make a significant difference to capture time requirements? Also, I know that I can shoot Ha even when there is moon around. I believe that shooting OIII is not recommended when there is moon. What about SII?

[swag72]

I personally don't think that the Baaders would speed things up or slow things down by any significant amount.

Regarding any NB filter - Don't believe the hype about being able to image during the full moon period. If you want good, detailed and gradient free data then you don't image with the moon about..... period. Ha is not immune I'm afraid.

[gnomus]

OK Sara.

[swag72]

OK Sara.

Only my opinion! I'm sure that others will disagree and accept the reduced quality in favour of actually collecting data. I'd say try it for yourself and see whether you think it's worth doing

[gnomus]

Only my opinion! I'm sure that others will disagree and accept the reduced quality in favour of actually collecting data. I'd say try it for yourself and see whether you think it's worth doing

Thanks for your advice Sara.  Even though I had a 90+% moon last night I pushed on and collected some more Ha.  I was happy with the 4 hours I had, although it was a little 'grainy'.  I managed to get another 2 hours 40 before the clouds rolled in for a total of 20x20 mins = 6 hours 40 of Ha.

I've tweaked this a little in PI and PS and the backgrounds are much smoother with the additional data - I think I am ready for some OIII and SII now [please click on image for better size]: