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Rosette Nebula NGC 2244 : 8 Hours worth


Catanonia
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Even with the bad weather and clear moon lit skies I managed to get 8 hours on NGC 2244 with the ED80

5 out of the 8 hours were last night under the full clear moon lit sky, so hopefully it isn't too bad.

Taken with Skywatcher ED80 ProII GOld 600mm F7.5 and EOS 1000D Baader / CSL LP Atronomik filter.

Subs of 15 mins mainly and some 5 mins thrown in as well. Darks and flats applied

Taken on 23rd and 30th November 2009 and combined with some light CS3 work.

Rosette Nebula Small.jpg

Larger and quality 12 JPG version can be seen here

http://extraview.dnsalias.com/temp/Rosette Nebula Large.jpg

Also attached the smaller version to the thread for keeps.

post-16631-13387741246_thumb.jpg

Edited by Catanonia
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Getting better Cat, all the time. Now that you have all the essential in place, have a look at the finer points. The stars show a bit of trailing. You could fix this in PS by nudging a copy layer down a pixel or two and another layer up a pixel or two with blend mode set to darken, but better to try and eliminate it altogether.

What might cause the trails? Is it one or two duff subs in the stack? Are the subs too long perhaps? Is it caused by differential flexure maybe? Or by polar alignment that needs a tweak? If your mount will hold a star centre stage for 20 mins without guiding, then it is likely differential flex causing an issue. You can double check all the fittings for security, but shorter subs may be a necessity. It is the reason I now use off axis guiding, I just couldnt get non trailed subs over 5 mins with a seperate guide scope.

Again, nice pic, the Rosette is one of my favourites :icon_eek:

TJ

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Hi Cat.

Thats lovely. And under a Full moon too!

I really cannot wait to have a serious stab at this one.

I did consider it last night (or the night before last) but settled for M42 as a target for short subs under such difficult conditions.

Well done, and thanks for sharing.

Bryan

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Thanks TJ for the tips.

To be honest I didn't check all the subs by eye, so could easily be a duff one or two in there.

I am using an ADM side by side mounting setup on EQ6Pro from FLO, so hopefully not got to much if any flex.

All things to check so thanks for the praise and tips.

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To be honest I didn't check all the subs by eye, so could easily be a duff one or two in there.

I am using an ADM side by side mounting setup on EQ6Pro from FLO, so hopefully not got to much if any flex.

If you are using DSS, its an idea to let it register the pics first. You can then see at a glance if any have a particularly bad "sky background" score, and also if the number of stars is vastly different between pics it will give you an idea that something is up.

But nothing beats the human eye for spotting errors, and a quick scroll through each sub to check for trails is more than worth the end result. Dont be tempted to keep any dodgy ones, you will lose more than you gain.

I have the same system and wrote off flex as the cause of trailing for ages:cool:

Cheers

TJ

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Very nice indeed. What is there to add? Well on my rather punishing monitor there is a sight green bias in the background sky, more noticeable close to the nebula. But that's very good. Modded DSLRs seem to have good Ha response which is what this needs.

Olly.

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