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Mars, 8-8 and 8-11, C9.25

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#1 JMP

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Posted 11 August 2020 - 07:00 PM

CSC forecast 4/5 seeing this morning and on Saturday morning, 8-8. This morning seeing was much worse than Saturday. My friend Ray has suggested I need to crank up the frame rate so I gave it a try. On Friday I was shooting about 100 fps, this morning I reduced the ROI and the exposure time, increased the gain, and shot about 200 fps. On Friday my avi's were 3 minutes long, about 20,000 frames, and I stacked the best 10%. This morning my avi's were 4 minutes long, about 48,000 frames, but I only kept 5%.

 

It was harder to focus with such average seeing, but it looks like shorter exposure may work out for me. I do like the smoother images I get with the lower gain though. Both images are 150% of capture scale.

 

Jeff Phillips

 

Mars, 8-8, 11:32 UTC, 10% of 20,000 frames:

 

Mars_8-8-2020_11-32_UTC.jpg

 

Mars 8-11, 12:16 UTC, 5% of 48,000 frames:

 

Mars_8-11-2020_12-16_UTC.jpg


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#2 sunnyday

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Posted 11 August 2020 - 07:30 PM

superb details , thanks .


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#3 Stellar1

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Posted 11 August 2020 - 07:41 PM

That’s one sweet image of Mars, I’m no imager but, I think you have the color bang on.


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#4 Kokatha man

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Posted 11 August 2020 - 09:35 PM

A nice pair of Mars images Jeff! waytogo.gif waytogo.gif


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#5 KiwiRay

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Posted 11 August 2020 - 09:43 PM

Nice work, Jeff.  Have you tried balancing the colours? One sign the colour balance is off is orange polar ice.


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#6 JMP

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Posted 12 August 2020 - 08:36 PM

Thank you, Darryl, and sunnyday, and Stellar1, and thanks for the likes as well. Ray, as you know there is some controversy about color balance. Here's a Hubble image, the full size version shows patches of red dust on top of the ice. (Hubble, August 27, 2003).

My idea is to try to match the color I saw in the eyepiece which will never be perfect. Here's an effort to make the color similar to the Hubble image:

 

Hubble, 8-27-2003

 

Hubble_Mars_8-27-2003.jpg

 

Mars, 8-11-2020, 12-16 UTC

 

Maes_8-11-2020_12-16_UTC_adj.jpg



#7 KiwiRay

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Posted 13 August 2020 - 12:36 AM

Fair enough.  "Controversy" seems a little strong - there are just different preferences.


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#8 DMach

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Posted 13 August 2020 - 12:56 AM

Nice comparison Jeff!

 

I have found similar results when testing high versus low frame rates, i.e. that there's a tipping point (which seems to be related to gain) where the noise becomes difficult to manage. I've always wondered whether this is related to how hot it is here - my camera routinely reaches 40 degC whilst imaging.

 

So I prefer to use "lower" frame rates (80-100fps) and live with the blurring if the seeing is not cooperating. I'd just end up doing more denoise, which blurs detail anyway.

 

And yes, before others on the forum chime in: I likely experience better seeing on average as I'm near the equator. I know, I know.

 

My point still being that you should test for yourself and find what works best for you.  :)


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#9 JMP

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Posted 13 August 2020 - 10:53 PM

Thanks Ray and  DMach. I like this forum because it gives me the chance to learn and get better.

 

Here's one with two stacks de-rotated, and colors adjusted similar to the Hubble image above.

 

Jeff

 

Mars 8-11-2020  11:23.1 UTC

 

Mars_8-11-2020_11-23_UTC_adj.jpg

Attached Thumbnails

  • Mars_8-11-2020_11-23_UTC.png

Edited by JMP, 14 August 2020 - 06:54 PM.

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