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Double Cluster with 200mm lens and astrotrac


Dave Smith

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This is another image taken at our club's astro-camp in darkest Suffolk. When I originally processed this, it was basically rubbish, very noisy and little star colour so was abandoned. Last night I was having a play with MaximDL to try and sort stacking of DSLR images. The auto features didn't seem to work, so stacked it manually. i.e. Separately stacked the darks and flats using average and saving as fits masters and then calibrating the lights before stacking using SD mask. The result was miles better than with DSS and although not that good it is good enough to show.

It consists of just 18 x 2 minute subs. The first one is zoomed in to see the detail of the central region and the second shows the full field in the 200mm lens.

Double%20Cluster-01cr.jpg

Full field

Double%20Cluster-01.jpg

I think to improve on this I need to use a telescope rather than just a camera lens.

Dave

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Don't underestimate the 200L, Dave. Focus is ludicrously critical. I use one of these things from TS. Honestly it makes all the difference. I think that if you can nail the focus this lens can match most optics of similar size.

http://ollypenrice.smugmug.com/Other/Takahashi-EM200TEC140/i-4TCd6Px/0/M/IMG1193-M.jpg

Olly

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Don't underestimate the 200L, Dave. Focus is ludicrously critical. I use one of these things from TS. Honestly it makes all the difference. I think that if you can nail the focus this lens can match most optics of similar size.

http://ollypenrice.s...M/IMG1193-M.jpg

Olly

Thanks for the tip Olly. With my DSLR I use the automatic focus in APT which seems to scan through the FWHM values and calculates where the minimum value is and moves the lens to that position. It can also be done "manually" without touching the lens.

When I eventually get round to sorting out using the lens with my CCD camera, that focus controller looks just the job.

Dave

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Thank you iksose7 and Clive for your kind comments.

@Velvet - sorry you can't see the images. This is the first time I have used DSS AND Maxim so cannot really comment. I intend to look a bit more into it because the difference was quite marked. Firstly I am going t redo this image with DSS to check that I did use it properly and hadn't altered one of the settings.

Dave

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Thanks Guy. Any requests for more tutorials?

Dave

There is always room for more tutorials Dave :grin: its amazing how 6 months drought from imaging can play havoc on the memory :embarrassed:

I'm waiting for a video tutorial on 2GV star calibration?? :rolleyes:

.

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Don't underestimate the 200L, Dave. Focus is ludicrously critical. I use one of these things from TS. Honestly it makes all the difference. I think that if you can nail the focus this lens can match most optics of similar size.

http://ollypenrice.s...M/IMG1193-M.jpg

Olly

They look good but I can't find it on their web site. Anyway, I think I'll make something up myself :)
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