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Mars - September 21 - very good seeing

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11 replies to this topic

#1 Pete Gorczynski

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Posted 21 September 2020 - 09:04 PM

I have a problem with data overload. Seeing was very good last night. I was out between 11PM to 4:30AM. I managed to collect about 200GB of data in two laptops, filling up one of them. I spent a good portion of the day today backing up the data and cleaning out the laptops so that I can go out tonight and do it all over again. This image is just the tip of the iceberg.

 

Pete G.

 

Mars-2020-09-21-0519-RGB-Rev1.jpg

 


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#2 Ittaku

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Posted 21 September 2020 - 10:39 PM

What a lovely problem to have! I've discarded 100s of gigabytes of blurry crap from many windy nights in a row now. I'll take your problem any day.



#3 JMP

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Posted 21 September 2020 - 11:14 PM

Beautiful image, Pete! How do you get such lovely edges on Mars?

Edited by JMP, 22 September 2020 - 10:41 AM.

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#4 R Botero

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Posted 22 September 2020 - 02:09 AM

Fantastic! Keep busy and them images coming Pete :waytogo:

Roberto

Edited by R Botero, 22 September 2020 - 02:10 AM.


#5 Mirzam

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Posted 22 September 2020 - 08:15 AM

I’d also like to see more, especially from the latter part of your time window.  I was out last night and had a very similar view to your excellent image.  

 

JimC



#6 sfugardi

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Posted 22 September 2020 - 12:02 PM

Pete, awesome image! Since moving to MA I have noticed that you are consistently getting better seeing in CT on the same night that we both imaged. I do miss my old CT dark skies. Details look great, especially the polar cap. I keep burning my cap. What brightness histogram did you capture at and do you protect the cap while you stretch the rest of the globe? Congrats on this one and thanks for posting it

 

Regards,

Steve



#7 astrovienna

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Posted 22 September 2020 - 12:42 PM

Fantastic image, Pete.  Is this a derotation?  If you have time to give some quick details about your capture routine, it would be appreciated.

 

Kevin



#8 KiwiRay

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Posted 22 September 2020 - 12:52 PM

This is a terrific image, Pete.  And you're right - I can't really make out the Arsia Mons cloud at all in this image from 2-3 hours before mine.



#9 Pete Gorczynski

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Posted 22 September 2020 - 07:49 PM

Beautiful image, Pete! How do you get such lovely edges on Mars?

Dodge and burn plus using masked layers. All done in Photoshop.


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#10 Pete Gorczynski

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Posted 22 September 2020 - 08:02 PM

Details look great, especially the polar cap. I keep burning my cap. What brightness histogram did you capture at and do you protect the cap while you stretch the rest of the globe? Congrats on this one and thanks for posting it

 

Regards,

Steve

I usually try to capture at around 70-80%. Sometimes it will go to 90%. The important thing is to never allow the image to saturate during capture. If you saturate then, that data is lost forever. I also pay attention to the histograms in each step of the processing to avoid saturation. However if you screw up during processing, you can always go back and redo it. Something that I learned working in the aerospace industry is to treat raw data like gold.

 

Pete G.

 


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#11 Pete Gorczynski

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Posted 22 September 2020 - 09:26 PM

Fantastic image, Pete.  Is this a derotation?  If you have time to give some quick details about your capture routine, it would be appreciated.

 

Kevin

Thank for the compliments, Kevin. I do not derotate. I haven't really played around with WinJUPOS a lot. Capture routine goes like this. First the basics, collimation check, thermal stabilization, etc. I have a permanent setup so that's pretty easy. Focus on the R channel. That's where most of the image detail comes from. Easy to do when the seeing is good, not so easy when the seeing poor. I focus directly on the planet and nothing else. Motorized focuser is a must. When I have the focus perfect on the R channel, I check the other channels. I have a motorized filter wheel, so it's easy. I do 3 minute captures on R and G each and 4 minutes on B. I usually try to keep the gain around the middle. High gain means high noise. With good transparency, I use 4ms shutters on R and G and 7.5ms on B. I use as small of an ROI as possible to allow for the highest frame rates. During capture make sure you never saturate the histogram. I save files as 8 bit SER. So that's pretty much it for the capture.

 

The next step is to back up all the raw data before processing. Some may think this step is unnecessary, until they lose their raw data for some reason.

 

I use Autostakket 3 for alignment and stacking. I will use a single alignment point to initially sort through the gigabytes of data. If something looks good I will try to use multiple alignment points to extract more detail. Depending on seeing, I will stack anywhere from 2% to 75% of the frames.

 

I process each channel individually. Then I do an initial sharpen and de-noise in Registax. Save file. Go to Astra-Image for deconvolution. I only use Lucy-Richardson. Gaussian point spread function, small for good seeing, large for poor seeing. Save file.

 

Then I go to Photoshop and for each channel I do rind and halo removal. I also do some high pass overlay filtering to extract additional detail. Then finally I combine each channel to a color image. I manually align the channels. Adjust color and brightness. Then for Mars, I usually finish with a R channel high pass overlay.

 

Pete G.


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#12 astrovienna

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Posted 23 September 2020 - 12:32 AM

Thanks for all the details, Pete.  Very helpful.

 

Kevin




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