Deminishing returns.....

Started 3 months ago | Discussions thread
thinker Regular Member • Posts: 224
Re: Deminishing returns.....

Astrozoid wrote:

Kemo-sabe wrote:

Astrozoid, you are correct in your analysis. The images were shot in Bortle 9 sky and consist of 193 5 minute subs with a Canon FD 800mm f5.6l lens with a Canon 5D MKIII at iso400 incorporating an Optolong L-eNhance dou-band 2" drop-in filter. My guide scope consist of a DIY Canon FD 300mm f4.0l lens coupled to a QHY5LII-C guide camera. The Mount is an iOptron CEM25P with ADM side by side saddle and iPolar scope for polar alignment. I have Pegasus power distribution for the mount/equipment and dual Pegasus focus controllers for remote focusing the primary optics and guide-scope.

I am a newbie to processing astro images. It has has taken me more than 1 year to automate and dial-in the hardware software aspects of astro imaging and learn the nuances of the system.

However, astro processing is another story. I was to embarrassed by my pitiful results to post such a sad image in the light of so many awesome images that I have seen on this forum. Pride is a terrible thing.

My son suggested that I post the image to see if I could get some advice and input on what I am doing wrong in my processing workflow. Or, is this the best that one might expect from Bortle 9 skies with the optical equipment I am using or a combination of both?

I am using Clarke's methodology of in camera dark frame extraction for the subs. Using Clarke's Methodology the subs actually take 10 minutes to shoot per sub. I use Sequator and/or DSS for stacking. PS RC-Astro filter GradientXterminator to remove gradients. Then RNC stretch or PS to stretch. StarTools or DxO PhotoLab4 Post Processing.

I have been experimenting with Canon's DPP4 RAW processor to process and convert the RAW subs to TIFF prior to stacking with varying results. In an attempt to pull more fine detail from the subs.

Post a link to the raw, linear stack and we'll see if there is more there to be brought out in processing.

Jerry

Could you please comment on the use of ISO400 with 7.8 electrons read noise vs ISO3200 (2.4 electrons) or even ISO6400/ISO12800 (with his filter)?

And the use of in-camera dark frame subtraction, as a misunderstanding of Roger's "On-Sensor Dark Current Suppression Technology", besides doubling imaging time?

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