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andre808

M51 from 27-02-14, a little disappointed.

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Hi all been dabbling in imaging for a bit, not completely new to it. Just looking for some pointers as to what i might be doing wrong. Equipment was 130pds on RA motored EQ5, coma corrector, Canon 350d. Had to dump some of the subs due to passing cloud. 115 60s with 21 flats darks and bias. Stacked in DSS, proccessed in GIMP. I normally stick to 800iso but used 1600 to cut exposure time down due to no guiding (as yet). Just used the recommended settings in DSS and what little i know about using GIMP i got from Mr Richards excellent book. It is cropped so even more noisy for it. I always have problems with the sky background, being unevenly lit. Light pollution here is as bad as it  gets, so sure that dont help. Anyhow i was made up to get 2 hours in and thought i would have had something a little better. Hey Ho.

post-21095-0-60302700-1393889895_thumb.j

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Not bad at all, without any tracking.  Thanks for sharing, as it provides me optimism moving forward to eventually get back into taking subs again.

Mike

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you`ve got more out of your image than i did of my efforts, took 14 5 minute subs and hardly any colour and it still looks washed out

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seen and done worse myself! dont be too harsh on yourself, for an-guided image its not to bad at all. 60 secs is a pretty short exposure, i would have another play with it, but be little more gentle with the processing. adjust the colour a little and dont try to push the image to far.

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Well done! Just been imaging M51 last night with 300s exposures. Hope I'm getting a result as good as yours (130pds, Canon450D - guided).

Don't be so harsh on yourself. Btw - AstroBin is an excellent site to put your pics up on and link into this forum! (See signature)

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That is a great image. I'm sure someone will be able to help on how to get rid of the glow coming from the bottom right.

Some of us dream about getting that sort of image, patience and a lot of experimenting is often required.

Keep posting them with at least the quality you have and you get a lot of happy faces  :smiley:  :smiley:  :smiley:  :smiley:  :smiley:  :smiley:  from people reading the forums.

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Good first one but you need a lp get a good one not the cheap skywatcher one ,

Pat

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Gradient Exterminator gets rid of the gradient but I don't know if there is an equivalent in Gimp.

Dave

post-2007-0-75073100-1393926187_thumb.jp

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I wouldn't be disappointed with that - think you've got good data there, just needs a little bit more on the processing:

- +1 for gradient exterminator

- think your stars and galaxy cores are slightly white-clipped

- bit of noise left

- and the colours are a bit whacky

i don't know GIMP so can';t advise how to do those sry.

please take as constructive criticism, and feel free to ignore, I think you've got the bones of a cracking photo

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When you stack in DSS and its finished move the middle RGB/K Level sliders so they sit all together over the bottom of the dotted line, the angle of the dotted line can be altered by playing with the midtone slider in Luminance, this image has been altered in DDS and the converted to Jpeg in Photoshop with the Levels slider moved next to data,,,, 800iso @ 60seconds X 10 couple of alteration done in Photobucket editor, i will learn some Photoshop someday....

m51-800-60-1.jpg

Edited by Tinker1947

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That's a great first start! The galaxy is quite faint at mag 8.4 and is quite a difficult target. You did great getting it at only 60s.

Can you line up the colour chanels in GIMP? If so, try that towards the start of the processing and see how that goes.

As has been said, don't know how you'd remove the sky glow in GIMP.

If you can get an Astronomik Clip-in Light Pollution Filter for your camera it'd be well worth it. I never use my Canon without my filter. They're a little pricy, even second-hand, but invaluable.

Alexxx

Edited by Astrosurf

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There's another cheat for getting rid of skyglow type gradients. If you make a copy of the image and clone stamp (or equivalent) the features, target and larger stars you can then stick a massive blur on it, flatten the image and bung it on the original in subtract/difference mode and it takes away a surprising amount of the gradient.

Can be laborious but what isn't in this lark eh?

cheers

Chris

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In fact I had a quick go and here are some images to show you what I mean. Obviously you'd get way better results with the originals and this only took about 5 minutes but you get the idea.

Original:

post-31053-0-14258900-1393939300_thumb.p

Clone stamped stars out:

post-31053-0-30419400-1393939355_thumb.p

Clone stamped target out:

post-31053-0-77014400-1393939379_thumb.p

Hefty blur:

post-31053-0-01988300-1393939699_thumb.p

Plop it over the original and change mode to subtract:

post-31053-0-58872300-1393939767_thumb.p

Bit of curves and you get the idea:

post-31053-0-88890100-1393939820_thumb.p

Not sure what the Gimp equivalents to these photoshop commands but I bet there is something similar.

cheers mate

Chris

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Thanks for the nice comments, some good improvements there. I guess i will have to learn more about using Gimp, it totaly baffles me. I can use some of it ok. After reading various articles. I dont have to much trouble getting good polar alignment, so tracking is usually fine. Over the 2 hours i spent on M51 it remained in virtually the same place in the frame. Have done up to 90 seconds in the past. This was my second attempt at M51, the first was with a 80mm f5 Acro, so some false colour. Reckon getting more subs would help to. I do need to replace my steam powered computer too, which should speed up the stacking and proccessing. I will look into the Lp filter when funds allow. And i would like to add that the 130pds is a cracking little scope, only had it a couple of months, but its done nothing but rain since then. Possible clear night tonight, so might get out again. 

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TBH - buying expensive equipment should include some investiment into post-processing software. There are older photoshop versions out there, that are by far less costly than a new one! Or of course, you could go for Pixinsight, which some people swear by.

I went photoshop and got this book from Lodriguss about AP with DSLR's. He takes you through basic and advanced postprocessing steps in photoshop - first on daylight images - then on ap subs.

This book is not a replacement for playing with photoshop yourself - not by a mile - but it gives you the tools to play with - understanding a bit more, what you are doing.

http://www.astropix.com/GADC/INTRO.HTM

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It's worth mentioning that Adobe CS2 is still available for free download due to the licencing server being taken down.

You will need an Adobe account but that's free to set up.  Just Google "CS2 download".

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Excellent! And I once bought Version 8 (with CS ?1 - had no number) for 10£ somewhere a while ago...

But I'm much happier now with CS5.

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Thanks for the nice comments, some good improvements there. I guess i will have to learn more about using Gimp, it totaly baffles me. I can use some of it ok. After reading various articles. I dont have to much trouble getting good polar alignment, so tracking is usually fine. Over the 2 hours i spent on M51 it remained in virtually the same place in the frame. Have done up to 90 seconds in the past. This was my second attempt at M51, the first was with a 80mm f5 Acro, so some false colour. Reckon getting more subs would help to. I do need to replace my steam powered computer too, which should speed up the stacking and proccessing. I will look into the Lp filter when funds allow. And i would like to add that the 130pds is a cracking little scope, only had it a couple of months, but its done nothing but rain since then. Possible clear night tonight, so might get out again. 

honestly, your data is good enough (well the stars are a tad eggy maybe), but you'll need to put in some time on the processing, I think you'll be surprised what you can get out of the above shot

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Do you still have the original autosave.tif? If so then upload it via a file sharing site and I'm sure some of us would love to have a play.

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Will have a look at CS 2, eggy, didnt know you could get computers which produce odore. LoL. Yes i thought they where too. I dont have an account with any of the file sharing sites. Might remedy that when i get a new refurbe computer in next couple of weeks. 

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This Orion and Running man where taken in December when i got the 130pds. I have reproccessed the original TIFF. Just used levels to get rid of light polution, and put a shallow s shape in curves. The TIFF was 188mb so my abacus was very slow using GIMP. Anyhow i still have the glow from the right, its there no matter what part of the sky i am imaging. So i guess that rules out nearby street lights. Any ideas, or is it just the limitations of gear and sky conditions. I was happy with this picture, i know the middle is washed out, but not got round to blending different length exposures yet.

post-21095-0-37397900-1393985435_thumb.j

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It's worth mentioning that Adobe CS2 is still available for free download due to the licencing server being taken down.

You will need an Adobe account but that's free to set up.  Just Google "CS2 download".

Will have a look at CS 2, eggy, didnt know you could get computers which produce odore. LoL. Yes i thought they where too. I dont have an account with any of the file sharing sites. Might remedy that when i get a new refurbe computer in next couple of weeks. 

This keeps popping up. Just to be clear, the Adobe CS2 downloads are intended for people who have previously bought a full licence to use the software. It is not a 'free' download and treating as such is illegal. As SGL, and astronomy in general, relies very heavily on software and developers, we take a very dim view on people openly recommending illegal software or file sharing  :police:

Please see here for further info: http://stargazerslounge.com/index.php?app=forums&module=extras&section=boardrules

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