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First real attempt at Deep sky imaging

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19 years 10 months ago #4304 by larrylart
Replied by larrylart on topic Re: First real attempt at Deep sky imaging
A very nice shot Michael! Yes, registax I used as well to align/stack images. I only used Photoshop to rotate them since I have better control there. Also in registax I think using manual align for dso is best since in most of the cases signal is to weak to get a good auto-alignment.

Larry

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19 years 10 months ago #4315 by dave_lillis
Replied by dave_lillis on topic Re: First real attempt at Deep sky imaging
Michael,
A definite improvement, that central star is definitely there now, as opposed to just hinting at it last time.
The second star is just about there also.
Interesting that the central area is much brighter then in the shot I got.
I'll put it down to the number of pics stacked. :?:

I did think that your previous shot looked very slightly blurred, as if the stacking allignment was not quite there, it seems to be somewhat cured in the new shot.

It has to be said that the processing after the pics are taken is four fifths of the work, a good digital picture is all down to the processing, its amazing the detail that can be pulled out of an image given how weak the initial pre-stacked images are.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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19 years 9 months ago #5019 by dave_lillis
Replied by dave_lillis on topic Re: First real attempt at Deep sky imaging
I was out at the scope a few week ago taking shots in what was probabily the only decent clear sky for weekks, and got this shot of the core of M31.

homepage.eircom.net/~sac/graphics/deepsky/m31_d.jpg

Its from stacking 5 30 second frames awith a bit of tweaking using photoshop,
Its only the core, but if you turn your monitor contrast up full and your brightness to about 1/3, you can see it as I intended.
to be honest, i didnt think I'd see anything, but you can see faint whisps of darkness around the core.
I found that running auto levels auto contrast first just to see whats there very useful, before you try any fine adjustment, I then undo them to return to the original image.
The immediate core is over exposed, I'm sure that there must be a way in photoshop of not overdoing the core yet bring out the detail around it.
Has anyone else done this ??
Next time I'll use a focal reducer, this would yield a brighter wider field of view.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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19 years 9 months ago #5061 by larrylart
Replied by larrylart on topic Re: First real attempt at Deep sky imaging
Actually, funny enough I had a similar attempt some two months ago when was cloudy all over but “crack” wide enough in the middle where Adromeda was. From what I know you need a little bit more then a focal reducer to catch this galaxy is to big … wither just a good lens or else you will need to workout a mosaic … :?



Also, processing is very catchy at least from my perspective with all alight pollution do to the fact that this is so big is hard to find a point in the image where to compensate for noise without running over the detail in the galaxy.

Larry
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19 years 9 months ago #5062 by michaeloconnell
Replied by michaeloconnell on topic Re: First real attempt at Deep sky imaging
Both very good images.
To be honest, I'm not sure what else you can do. There's bound to be some way of reducing the luminance of the centre and increasing the detail in the edges. But, as Larry said, it's a massive target. Perfect for those with a small refractor. A SCT may have too narrow a FOV for it which id why you're only getting the core.
Dave, it might be worth trying to piggyback your 4" celestron refractor on the 12" and taking some images of M31 that way. This would give you a much better FOV.

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19 years 9 months ago #5090 by dave_lillis
Replied by dave_lillis on topic Re: First real attempt at Deep sky imaging
Lads,
M31 is obviously too big for the SCT, but I was hoping that I could atleast catch better dark lane deffinition that that, I think next time I'll use the 4 inch refractor, it has a FOV of over 2.5 degrees with the canon.
Would imageplus be able to dim the bright center.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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