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L-enhance 2nd light - Edge 8 - ASI071MCpro - NGC6888

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#1 John Miele

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Posted 19 August 2019 - 06:38 PM

This is my second processed image with the L-enhance filter. I actually took these subs 2 days before my AT115 image so these were taken on the night of and after the full Moon in my red zone backyard! 

 

I used my Edge8 @ f10 which produces blows away the .7x reducer on the corner stars. So it's either enjoy the reducer speed and crop heavily or slog along @ f10 speed but with no need to crop out ratty looking corner stars at all which is what I did here. This is 114x 180 second subs at unity gain. And at f10 I still needed even more time! But this was every sub I could collect over two nights.

 

I processed it the same way as the AT115EDT image.

 

https://www.cloudyni...t/#entry9581322

 

I think it's neat to compare the different results with same duration subs at f5.6 and 644mm vs f10 @2030mm. More detail and resolution in the Edge8 but I think richer colors and in the AT115EDT.

 

I have the full frame resized to 1600x1200 for posting and then a cropped frame at 1 arc-sec/pixel scale. I stretched this a bit too hard and started getting some combing in the histogram and some noise. The background has a sort of washed out dark look that I don't really like too much. But it will be fun to do more work with this new filter and learn how to process it the best way.

 

Thanks for looking and C&C are always welcome...

 

cs...John

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#2 John Miele

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Posted 19 August 2019 - 06:38 PM

Cropped version here...

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#3 AhBok

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Posted 20 August 2019 - 09:38 AM

Very nice John. I think you might could even boost the stretch a small bit, though it may be my display. I’ve enjoyed playing with L-eNhance the past full moon. I find blending the NB data with the RGB taken on moonless nights to also be a superb use for this filter.

#4 mewmartigan

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Posted 20 August 2019 - 10:55 AM

John,

 

Thanks for sharing. I have an L-eNhance but no chance to use it yet. With my Optolong L-Pro I have been using 180 subs to get above read noise but avoid wasting too much time dithering (every other) with shorter exposures and avoiding an excessive number of sub frames.

 

Do you think 180s subs with the L-enhance is good? I was think 4-5 minute subs but if I can still get away with 180s that could reduce subs wasted due to airplanes and tracking errors. I am at f/5.5 by the way.

 

Thanks!


Edited by mewmartigan, 20 August 2019 - 10:56 AM.


#5 John Miele

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Posted 21 August 2019 - 12:10 PM

Hi Marcus,

 

Based on results from my AT115EDt @ f5.6, I would say 180 seconds at unity gain is the shortest I would try with the L-enhance. I think a higher gain and/or 240 to 300 seconds would be better...give you stronger signal. My signal was faint and required a lot of stretching. I also dither every other frame as well. I know what you mean about the dithering time loss. Between autofocusing and dithering I only captured 48 x 3 = 144 minutes over a 3 hour time span. That's an 80% efficiency....hmmm...I guess that is not too bad.

 

Now on my Edge8 @f10, 180 seconds at unity gain was clearly not enough. From memory my mean ADU was only around 270 for the subframes. I think that should be higher but I was just experimenting with these first tries. I'm going to use 300 second subs with my Edge8 next and see what kind of mean ADU values I get.

 

John


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#6 elmiko

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Posted 21 August 2019 - 02:41 PM

Nice image John! You have done a great job on the processing too. 

Don't you love this filter?

Clear skies, Mike



#7 John Miele

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Posted 21 August 2019 - 03:02 PM

Thanks Mike! Yes I only just started with it but it really lives up to its reputation. Can't wait to try blending this with some rgb data. Need more clear nights!!!
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#8 mewmartigan

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Posted 21 August 2019 - 09:12 PM

Hi Marcus,

 

Based on results from my AT115EDt @ f5.6, I would say 180 seconds at unity gain is the shortest I would try with the L-enhance. I think a higher gain and/or 240 to 300 seconds would be better...give you stronger signal. My signal was faint and required a lot of stretching. I also dither every other frame as well. I know what you mean about the dithering time loss. Between autofocusing and dithering I only captured 48 x 3 = 144 minutes over a 3 hour time span. That's an 80% efficiency....hmmm...I guess that is not too bad.

 

Now on my Edge8 @f10, 180 seconds at unity gain was clearly not enough. From memory my mean ADU was only around 270 for the subframes. I think that should be higher but I was just experimenting with these first tries. I'm going to use 300 second subs with my Edge8 next and see what kind of mean ADU values I get.

 

John

John,

 

Thank you for the detailed info. I prefer to keep things at unity gain for simplicity so I will give 5 minutes a shot on the next clear night...should only be a year or two. cloudy.gif 




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