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Adding more data with a wide FOV

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#1 limeyx

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Posted 14 April 2021 - 11:18 AM

Not sure if this belongs here or beginning imaging.

 

We've had a "unicorn" of a week here with new moon and clear skies all week so I've been out imaging.

I've been focusing on M97/M108 because I only have a wide FOV scope (360mm) so these objects by themselves are pretty small.

 

My plan was to spend 5 nights on this and I am 3 nights in. 

My concern is that due to the small number of pixels I will have dedicated to each of these, does adding more data make sense ?

 

I've stacked the first two nights and saw maybe a marginal improvement. So far it's around 5.5 hours (Bortle 6) and I added 3.5 hours last night which I am adding in. I also experimented last night with shorter subs (60s instead of 180s)

 

For tonight & tomorrow, my decision is whether to keep adding data OR call it "done" and go do something else.

 

Any suggestions are welcome

 


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#2 limeyx

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Posted 14 April 2021 - 11:49 AM

Just to clarify my question here:

Given that I can only get a small number of pixels on a small nebula or galaxy, will adding data really be effective in getting the detail out or is this a dead-horse situation?


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#3 gcardona

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Posted 14 April 2021 - 12:36 PM

Adding more subs and integration time does not increase your resolution, it only increases your signal to noise ratio. What you want to do is make sure you dither your subs and then use drizzle integration. Drizzle integration, along with dithering, can effectively increase your resolution. By dithering, you move the image around from one pixel to the next so over time and multiple subs, the information between pixels is filled in and then the drizzle integration process brings out this extra data. This technique is ideal in your situation where your targets are under sampled.



#4 limeyx

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Posted 14 April 2021 - 12:46 PM

Adding more subs and integration time does not increase your resolution, it only increases your signal to noise ratio. What you want to do is make sure you dither your subs and then use drizzle integration. Drizzle integration, along with dithering, can effectively increase your resolution. By dithering, you move the image around from one pixel to the next so over time and multiple subs, the information between pixels is filled in and then the drizzle integration process brings out this extra data. This technique is ideal in your situation where your targets are under sampled.

Thank you. I do dither (around 16 pixels on the D5300 - random) and I've been doing "CFA drizzle" either at a scale of 1 or 2 in PI integration.

 

I don't think my sampling in arc sec/pixel is inline with the recommendations for 2x drizzle but I am playing with it. Also deconvolution and HDR transform to try to bring out detail

 

Right now I am trying to bring out the red in M97 and I have some but not as much as I want 

 

With last nights data I will be at almost 9 hours and I can probably add 5-6 to that in the next two nights



#5 limeyx

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Posted 14 April 2021 - 12:50 PM

This is a super low-res lightly processed version of the first 2 nights (approx 5.5 hours)

 

 

Attached Thumbnails

  • M97-Drizzle_2_Preview_1-small.jpeg

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#6 limeyx

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Posted 15 April 2021 - 03:32 PM

I'm almost at 11 hours now and it's going to take a week to process this! Hoping to get 2.5 to 3 more hours tonight and call it good. My fan in my mac is going to melt processing.

 

I still dont think I brought out the red on all sides of the owl as in this image here

 

https://www.astrobin.../165823/?nc=all




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