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Old 18-10-2015, 02:08 PM
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alpal
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NGC 300 - only 3 hours of data. re-process

The clouds came over last night so I only got 3 hours of data on this very dim target.
10 minute binned 1x1 subs gave me almost no signal on the spiral arms
so I ended up doing 15 minute subs binned 2x2 for everything.
I wish I could have kept imaging all night to help get the noise out of the picture & to bring up the missing arms.
Maybe I can add to it on another night?
This is the first time I've tried this target & it's really too hard for the light polluted suburbs.

Taken with my new 10" f4 Newt. & QHY9 mono.
All binned 2x2 & all 15 minute frames.
6 Luminance frames
& 2 frames each of RGB.
Darks, flats & bias applied.

Larger version on flickr.

https://www.flickr.com/photos/247194...in/photostream


cheers
Allan


Edit - reprocessed using RGB as part of Luminance stack

This is a cropped version

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Last edited by alpal; 20-10-2015 at 12:49 AM.
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  #2  
Old 18-10-2015, 02:31 PM
Placidus (Mike and Trish)
Narrowing the band

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That you got anything at all from the 'burbs is a miracle. So tempting to stick with narrowband and bright emission nebulae, or bright things like globular and open clusters, but galaxies can be exquisite.

Your 15 minute 2x2 approach is working far better than with the 2 minute subs on NGC 253, so you're racing in the right direction.

Still too red. Understand that light pollution makes it virtually impossible to get right, but this galaxy is notoriously blue.

Absolutely definitely add another night or two of data. Worth the effort.

Very best,
Mike and Trish
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Old 18-10-2015, 02:41 PM
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DJScotty (Scott)
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Al, that is looking good.

I am assuming that has the CLS filter in place?

DJ Scotty
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Old 18-10-2015, 03:29 PM
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codemonkey (Lee)
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Good work on what's got to be a really difficult target in the burbs!

Looks like 900s, 2x2 subs are a good start on this one for you. You'll need to add many more subs to start bringing the noise levels down though, as you're no doubt aware. Keep at it until you get sick of looking at it, that's my new philosophy.
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Old 18-10-2015, 05:33 PM
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alpal
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Quote:
Originally Posted by Placidus View Post
That you got anything at all from the 'burbs is a miracle. So tempting to stick with narrowband and bright emission nebulae, or bright things like globular and open clusters, but galaxies can be exquisite.

Your 15 minute 2x2 approach is working far better than with the 2 minute subs on NGC 253, so you're racing in the right direction.

Still too red. Understand that light pollution makes it virtually impossible to get right, but this galaxy is notoriously blue.

Absolutely definitely add another night or two of data. Worth the effort.

Very best,
Mike and Trish

Thanks Mike and Trish,
Thanks - I'm just getting used to this new scope.
I'm sure would have been a whole lot better if I had taken sub frames all night.
I've never taken such long sub frames except with Ha.
I need a brighter target but the nebulas are gone for now.
Yes - it is too red but that's what came out
after sky glow & my CLS-CCD filter.
I'm working full time so it's difficult to get the time
on a target like this to do it justice.

cheers
Allan
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  #6  
Old 18-10-2015, 05:35 PM
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Quote:
Originally Posted by DJScotty View Post
Al, that is looking good.

I am assuming that has the CLS filter in place?

DJ Scotty

Thanks Scotty,
Yes - I really have to use the CLS-CCD filter.
I have a row of yellow sodium lights all down the road beside me.
I am surprised I can pick up anything.

cheers
Allan
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  #7  
Old 18-10-2015, 05:38 PM
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Quote:
Originally Posted by codemonkey View Post
Good work on what's got to be a really difficult target in the burbs!

Looks like 900s, 2x2 subs are a good start on this one for you. You'll need to add many more subs to start bringing the noise levels down though, as you're no doubt aware. Keep at it until you get sick of looking at it, that's my new philosophy.

Thanks,
Yes I could have gone to 30 minute subs binned 2x2 on that target with RGB.
NGC 300 is not for the faint-hearted.

I should post some RAW frames of binning 1x1 & 2x2 for 600s of luminance.
You can hardly see anything in the 1x1 subs except the core.

cheers
Allan
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Old 18-10-2015, 06:00 PM
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strongmanmike (Michael)
Highest Observatory in Oz

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For the sake of not being repetitive, I'll second everything Mike and Trish have said, keep persevering Al, you are improving every outing

Taking long exposures is not easy or even achievable for everyone, I think just about everyone knows now (surely) that in general to get a good image, especially of medium to faint deep sky targets, one needs plenty of exposure measured in at least several hours or more. Thing is, as you say, life needs to be lived too, so you do what you can huh? As Fred Hollows sort'a said, an image is an image, no matter if with a $70K RC from Germany or a home modified OTA from BINTEL

Mike
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Old 18-10-2015, 08:52 PM
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Quote:
Originally Posted by strongmanmike View Post
For the sake of not being repetitive, I'll second everything Mike and Trish have said, keep persevering Al, you are improving every outing

Taking long exposures is not easy or even achievable for everyone, I think just about everyone knows now (surely) that in general to get a good image, especially of medium to faint deep sky targets, one needs plenty of exposure measured in at least several hours or more. Thing is, as you say, life needs to be lived too, so you do what you can huh? As Fred Hollows sort'a said, an image is an image, no matter if with a $70K RC from Germany or a home modified OTA from BINTEL

Mike

Hi Mike,
I'm having fun doing what I can with what I've got - & made.


I add a picture here of the results of binning & stacking.
You can see how hard it is to pull NGC 300 out of the noise.
The jury is still out on binning.

cheers
Allan
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Click for full-size image (Binning comparison NGC 300_3.jpg)
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  #10  
Old 20-10-2015, 12:55 AM
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Hi Everyone,
I spent hours re-stacking my data.
I found that adding the 6 frames of Luminance to the 6 RGB frames & using
them as luminance too - using a blend of medium Kappa &
auto adaptive stacks in opacity of Photoshop I was able to create
a better luminance layer &
I also redid the RGB to give less colour to get a much better processing.
That way I doubled my Luminance data.
You can start to see the arms coming out now.
The old one was so awful that I deleted it.
The latest one is still noisy but it's better.

cheers
Allan

Last edited by alpal; 20-10-2015 at 01:21 AM.
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  #11  
Old 20-10-2015, 07:46 AM
Placidus (Mike and Trish)
Narrowing the band

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Yes! The elusive spiral arms are much improved. Colour now looking subtle but very pleasing. Well done.
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  #12  
Old 20-10-2015, 07:56 AM
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Quote:
Originally Posted by Placidus View Post
Yes! The elusive spiral arms are much improved. Colour now looking subtle but very pleasing. Well done.
Thanks Mike & Trish,
With a good night of data I could make a decent picture out of
this galaxy even though it's very faint.
It's amazing how much luminance information is in the RGB !

cheers
Allan
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