NGC6888

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Kevin Phillips

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Oct 1, 2021, 1:07:44 PM10/1/21
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Tonight's ago I captured  NGC6888.  5,000ly from earth commonly know as the Cresent Nebula. I capture 128 frames at 2 mins exposures. Plus 40 darks and dark flats along with flats. 
The zwoISA294 1 shot colour camera temp lowered to -15. I extend the mount on to a pillar to prevent the camera fighting with the tripod legs. Also I used light pollution filter which worked very well. Guiding was pretty good willam assisted me to gey a better resolution on the screen using phd2. I used sharpcap pro. A word on sharcap Pro. It had and excellent polar alignment on it I can get my polar to tru North bang in the middle. It also has a histogram (which I yet ti try out) to give me the optimal exposure time. 
The processing is always a challage for me but I am getting there. I process in Startools and later I will do some more work in photo shop. But anyhow here it is before photo shop Cresent nebula.
Kevin P






NGC6888_.JPG

JR

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Oct 4, 2021, 6:56:32 AM10/4/21
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Very good Kevin.  Lots of structure in the nebula and the Sharpcap PA obviously worked well.

The smart histogram in Sharpcap is straight forward and it only takes a few minutes to go through the automated routine.  I pointed my telescope at a white ceiling when the natural light was not bright, no focusing and that works.  You get a graph that looks very like the manufacturer's on the web site.  

Sharpcap stores the results and they get used when you choose the camera, giving you quick guidance in the smart histogram box for the exposure and gain combinations you set, in the form of green bars for satisfactory settings.   The more sophisticated version takes a sky darkness reading.   Point at a dark part of the sky and click.  It then suggests both gain and exposure times which you can click to apply.  They seem to give decent imaging results.   

You still have to set the number of exposures you want, as I discovered assuming the number of frames it calculates for you, after you set a total imaging time, were also applied automatically.   

James 

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On 1 Oct 2021, at 18:07, Kevin Phillips <thewels...@live.com> wrote:


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Kevin Phillips

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Oct 4, 2021, 7:03:29 AM10/4/21
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James I really want to apply the histogram and gain setting that sharpcap suggest.  I am not to good with  being explain to me but I pick things up faster when it is shown to me practically. But thank you fir your comments


From: 'JR' via croydonastro <croydo...@googlegroups.com>
Sent: Monday, October 4, 2021 11:56:19 AM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: Re: [croydonastro - 7016] NGC6888
 

Trish Bloxham

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Oct 4, 2021, 8:51:15 AM10/4/21
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What a  fabulous photo.  Well done and thankyou for sharing.

 

Sent from Mail for Windows

 

From: 'JR' via croydonastro
Sent: 04 October 2021 11:56
To: croydo...@googlegroups.com
Subject: Re: [croydonastro - 7016] NGC6888

 

Very good Kevin.  Lots of structure in the nebula and the Sharpcap PA obviously worked well.

William Bottaci

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Oct 15, 2021, 3:42:59 PM10/15/21
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Hello Kevin, this looks like one of the more picturesque images so far, and not only is the imaging good but the processing too. You're definitely learning and progressing, no doubt there.

If anyone has noticed the odd north and west lines on the brightest stars (north is directly to the right) that's because the first image included was taken whilst PHD2 (free guiding software) was still calibrating. PHD2 moves the mount in 2 directions to get an idea of how much it should make corrections if the star moves at all, which is to offset poor polar alignment and the gearing in the mount.
The thing is, Deep Sky Stacker (DSS) should have either thrown out this image or averaged out the lines, and one image in 128 means reduced to less than 1%.

We were also interrupted half way through by some high cloud.

Since processed without the offending first image, and between the clouds and what DSS reports as 'good enough' images, there are now 92 but I'm sure Kevin will post again soon...

Thanks for the advice James; we're ready to try out the smart histogram. We are committed to a gain of 120 for this camera as that is the Unity Gain - which roughly means the best compromise setting between sensitivity, noise and dynamic range etc. Also our Darks are set to 120.

Yes, thank you Kevin for sharing.
William




On Mon, 4 Oct 2021 at 13:51, Trish Bloxham <trishb...@hotmail.co.uk> wrote:
What a fabulous photo. Well done and thankyou for sharing.



On Mon, 4 Oct 2021 at 12:03, Kevin Phillips <thewels...@live.com> wrote:
James I really want to apply the histogram and gain setting that sharpcap suggest.  I am not to good with  being explain to me but I pick things up faster when it is shown to me practically. But thank you fir your comments



On Mon, 4 Oct 2021 at 11:56, 'JR' via croydonastro <croydo...@googlegroups.com> wrote:
Very good Kevin.  Lots of structure in the nebula and the Sharpcap PA obviously worked well.

The smart histogram in Sharpcap is straight forward and it only takes a few minutes to go through the automated routine.  I pointed my telescope at a white ceiling when the natural light was not bright, no focusing and that works.  You get a graph that looks very like the manufacturer's on the web site.  

Sharpcap stores the results and they get used when you choose the camera, giving you quick guidance in the smart histogram box for the exposure and gain combinations you set, in the form of green bars for satisfactory settings.   The more sophisticated version takes a sky darkness reading.   Point at a dark part of the sky and click.  It then suggests both gain and exposure times which you can click to apply.  They seem to give decent imaging results.  

You still have to set the number of exposures you want, as I discovered assuming the number of frames it calculates for you, after you set a total imaging time, were also applied automatically.  
James



On Fri, 1 Oct 2021 at 18:07, Kevin Phillips <thewels...@live.com> wrote:
Tonight's ago I captured  NGC6888.
5,000ly from earth commonly know as the Cresent Nebula. I capture 128 frames at 2 mins exposures. Plus 40 darks and dark flats along with flats.
The zwoISA294 1 shot colour camera temp lowered to -15. I extend the mount on to a pillar to prevent the camera fighting with the tripod legs. Also I used light pollution filter which worked very well. Guiding was pretty good, William assisted me to get a better resolution on the screen using phd2.
I used sharpcap pro. A word on sharcap Pro. It had and excellent polar alignment on it I can get my polar to true North bang in the middle. It also has a histogram (which I yet to try out) to give me the optimal exposure time.
The processing is always a challenge for me but I am getting there.
I process in Startools and later I will do some more work in photoshop. But anyhow here it is before photoshop Cresent nebula.
Kevin P

Kevin Phillips

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Oct 15, 2021, 6:19:14 PM10/15/21
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Thank you William for that explanation of Ng6888. 
I moved the image into photoshop and did some additional work I removed those tracking lines did some healing and enhance it a bit. 
Thanks kevin 
From: croydo...@googlegroups.com <croydo...@googlegroups.com> on behalf of William Bottaci <w.bo...@gmail.com>
Sent: Friday, October 15, 2021 8:42:41 PM
To: croydo...@googlegroups.com <croydo...@googlegroups.com>
Subject: [croydonastro - 7042] NGC6888
 
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