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M101 - Trickier than I thought


paulgrover68

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I thought I'd stack what I had - current around 3 hours. I want to add another 3.  I'm just getting used to the new scope. I also decided to push the gain a bit to allow for less imaging time (BST + Work).  Hoping a bit more data will give it some more "pop".  I was usimg 5 minute subs and Starlinks killed around 10, which was massively annoying!
 

M101 - Pinwheel Galaxy

 

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49 minutes ago, paulgrover68 said:

I thought I'd stack what I had - current around 3 hours. I want to add another 3.  I'm just getting used to the new scope. I also decided to push the gain a bit to allow for less imaging time (BST + Work).  Hoping a bit more data will give it some more "pop".  I was usimg 5 minute subs and Starlinks killed around 10, which was massively annoying!
 

M101 - Pinwheel Galaxy

 

Showing some nice colour creeping in on the outer arms. Setting gain can be tricky depending on your LP. High gain on dark skies with no LP is ideal. Once you start using high gain on LP skies, you amplify the signal, but also amplify the LP. When shooting OSC or broadband, I would err on the side of caution and go for longer exposures and lower gain, but that depends on your situation.

 

Brian

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That's a super point Brian - I'm Bortle 4-5. I think 200 gain is the most I'd chance.I have noticed it just starting to soften things.

I must admit, I've been using the L-eNhance for so long I forgot how much light the IDAS LPS filter let's through. Next round of galaxy shooting will be at unity I think.
 

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I’m in Bortle 7/8 and as Brian says higher gain results in amplification of light pollution especially with the OSC. So I now only shoot at unity which for both my cameras is oddly 111. But you get used to it. I have sometimes shot at 53 and recently 11! The latter due to a typo as I meant it to be unity. 

Also lower gain minimises the amp glow which my cameras are cursed with but which can be completely calibrated out.

 

Great work so far on the galaxy Paul.

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17 minutes ago, paulgrover68 said:

That's a super point Brian - I'm Bortle 4-5. I think 200 gain is the most I'd chance.I have noticed it just starting to soften things.

I must admit, I've been using the L-eNhance for so long I forgot how much light the IDAS LPS filter let's through. Next round of galaxy shooting will be at unity I think.
 

I believe the IDAS LPS is more suitable for LP from Led street lights. I am in Bortle 4, and I shoot gain 76 and offset 15 with my ASI 1600, and maximum 2 minute exposures on RGB and 1 minute on lum data.

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16 minutes ago, MarkAR said:

Some good detail starting to show. Definitely adding ore data will benefit.

With the starlink issue, did you use sigma clipping during stacking or just excluded the tainted subs?

I dropped them from this run. I was planning to try a stack with the least bad ones included - but then the sky cleared.   I think I do have to play with some settings to maximsise my subs.  

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1 hour ago, MarkAR said:

Worth ditching bad subs but Windsorised Sigma Clipping works well on satellite streaks going through good subs.

I never remove any images with satellite trails, only those with streaked stars. I blink all my images to remove obvious bad ones, then subframeselector to remove high eccentricity and high FWHM frames.

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