Author Topic: Is this data awful - or is it just my PI skill?  (Read 1057 times)

Offline jfulton

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Is this data awful - or is it just my PI skill?
« on: 2017 April 13 08:25:37 »
Hi Chaps,

I've just upgraded to a mono camera and filter wheel.  I think I've sucessfully managed to combine Ha with my Red channel, beyond that I've done nothing with this data apart from calibrate, stack, and combine the channels (for ease of download).

I am struggling to get a decent final result.  I know that's down to my poor skill - but I'm not sure which bit - is it my acquisition or my processing, or both.

i am wondering if anyone can do a quick and dirty process of this to show if anything worthwhile can be gained - if so, I'll focus my effort on learning more about PI, if not, I'll do more acquisition practice.  I know I need to do more of both, but the question is - which one first!

https://www.dropbox.com/s/olqeq94usgcbbl3/LRhaGBnoprocess.xisf?dl=0

files have had Ha combined with R as per Vicents process, and then I've done an LRGB combine.  No other processing beyond a crop.

thanks for looking

Jim

Offline RickS

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Re: Is this data awful - or is it just my PI skill?
« Reply #1 on: 2017 April 13 17:57:00 »
Jim,

Here's a very quick process of your data (MLT noise reduction, BackgroundNeutralization, ColorCalibration with galaxy as white reference, Histogram stretch, apply clipped lightness mask and Curves boost saturation and blue.)  Not sure if you consider this a decent result but I've seen much worse  ;)

The biggest deficiency I can see in the data is the softness.  I think you probably need to put more effort into getting good focus.  Maybe use a Bahtinov mask and refocus from time to time?  Your guiding must have been fairly reasonable as the star shapes are OK.

You don't mention the length and number of subs, but more data would help as well.  More data almost always helps  :)

Cheers,
Rick.

Offline Zocky

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Re: Is this data awful - or is it just my PI skill?
« Reply #2 on: 2017 April 14 16:01:52 »
Jim,

Your image is quite soft and definitely looks like you have a focus issue. So, getting the focus right should be your priority. Furthermore, you have a lot of chrominance noise, so be careful with that also. To reduce this chrominance noise I have extracted L component from your RGB file.
Processing on L component: HT, HDRMT, LHE
Processing on RGB: HT, convolution, color saturation

Next was LRGBCombination with chrominance noise reduction ticked.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline jfulton

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Re: Is this data awful - or is it just my PI skill?
« Reply #3 on: 2017 April 17 05:41:56 »
Thanks guys - I have struggled with my autofocus, after a while of blaming the equipment I stripped down my moonlite on Friday and two of the bearings are cracked.  I've replaced them today so hopefully it'll be getting better now.

Here is my best effort - it's encouraging to see what a little more experience can get out of the same data - you've answered my question though - more effort in acquisition needed first, then can worry about processing a bit later.  I often see references on here to garbage in - garbage out, so time to increase the quality of the input before focusing on the tweaks.

Thanks for putting in the effort and showing me there is hope for me yet!

Jim

Offline Zocky

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Re: Is this data awful - or is it just my PI skill?
« Reply #4 on: 2017 April 17 14:51:46 »
Well done Jim. No doubt, there is hope for you  ;)
One more advice. Try to keep the background on your images dark grey (not black). Value of the background should be around 0,09 to 0,1.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/