Extreme deepsky astrophotography

Hi folks.

Well it has been 2 weeks since I touched the scope, even though usually, regardless of work the next day, I will open up every time the skies are clear. This has to do with the fact is that, due to a combination of Myself/My site/my tube, I got extremelly frustrated with planetary imaging, that I needed a break from my scope…

So, these past 2 nights, I decided to get back to what I do resonnably well, namely deepsky astro-imaging. And, to celebrate my reunion with the telescope, I decided to shoot difficult targets: NGC7814 and IC5146. I had never done either of them so I thoroughly checked data on these objects and decided to spend a night each, since they are not very bright. For NGC 7814 (aka Caldwell 43), I decided to use 24x 600 Secs exposures which amounts to 4 hours in total. Transparency that night as well as seeing were average. Because the core of this galaxy is very bright and the extensions are very faint, it is quite a tricky subject to process, and I used Maxim’s ddp to adjust the galaxy:

NGC7814s

The result is quite pleasing to the eye. Also, the reason this post is titled “extreme astrophotography” is because, looking at the full-res picture (available in the C14 gallery) there are litterally 100′s of small galaxies on this picture… I managed to identify one of the brighter one whose magnitude turned out to be 21.46, so my guess is that the faintest magnitude visible here is at least 22. Mind you, I have never exposed anything for so long. I am generally never satisfied with my pictures, but I have to admit I really like this one.

Then, about IC5146 “cocoon Nenula”; I saw some stunning pictures of it on the NASA website, realised it was just the right size for the C14, so I decided to have a shot at it last night. After the first 10 minute exposure, I was not sure if I was going to get anything out of it, as the nebula was very faint. I went for 18×600 Sec exposures or 3 hours total exposure time. Because the more exposure, the better signal to noise ratio gets, once I finished combining all 18 shots, pushing the cursors a bit actually showed something. I then tried different techniques, filter, DDP with maxim, but I got the best result simply by adjusting the image curve… This is one very difficult object which necessitate very good transparency, as was the case last night. The resolution is quite good as well, since the smallest double stars are fully resolved.

IC5146curvess

This of course, is not a NASA picture, but I think it could get published by some astronomy magazine. Because it is a difficult object, you do not see amateur photographing it so often, as it is quite small and requires a long focal length to show as many details as possible.

Then, I wanted to do NGC 660 which is a beautiful galaxy, but, my sensor glass window decided to fog up after 5 exposures, so, it will have to wait. Tonight may be?

Serge

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