Author Topic: Mars  (Read 4364 times)

Levas

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Re: Mars
« Reply #25 on: July 29, 2018, 10:46:05 AM »
@Danne, uploaded here the original files:

https://drive.google.com/drive/folders/12c7fp5ymfV8YbmgA8p-otTZ6pk9Kp2U6?usp=sharing

Curious what other people can do with the stack-128frames.dng file.
I already used a lot of postprocessing in Lightroom to keep the darker site of the moon nice, it's rather posterized, since there is not much data there.
I unsharpened the darker part to get rid of the posterizing.

Levas

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Re: Mars
« Reply #26 on: July 29, 2018, 12:31:16 PM »
@Geggo

I see you're using a mto-11ca.
I bought a used Samyang 500mm f6.3 this week, also looked for a mto-11ca first, but they're all on sale half the world away and shipping costs are huge with that weight  :P
How is the handling of the mto-11ca, is it also a pain in the ... to get sharp focus ?
The Samyang is said to be really soft in focus, but I'm very happy with the results I got.
Biggest problem is the T-stop, it's almost 2 stops bigger then F-stop on these mirror lenses.
I've also read that some of these mirror lenses have a converter element at the back, not sure if the Samyang has one.
But I find it typical that the lens is about 120mm long, so if the light path is 3 times as long, as it should be for a mirror lens, then it gives about 360mm focal length, maybe add some 50mm more for the T-mount, then it could only reach about 400mm focal length  ???
Some say, if it has a converter element at the back, removing it could give much sharper results.

escho

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Re: Mars
« Reply #27 on: July 29, 2018, 02:15:53 PM »
Ah, what a shame @escho... here some km in the north of you we have seen a very little more. We also had some clouds but I don't have the right gear to make good photos...
You all got nice shots! :)
Yes, direction north to west all was fine. I saw a nice Venus going down and I saw a bright Jupiter up in the sky. In the other direction: Many clouds...

@g3gg0
Thanks for the data

@Levas
I cannot oven your dng-stack. darktable tells me: Unknown format and I see only the preview-pic. No clue why.
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Levas

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Re: Mars
« Reply #28 on: July 29, 2018, 02:46:47 PM »
@Escho

I've uploaded a new stacked file in the same map, 'NEW_Stack-128frames.dng'.
I took the stacked dng file and ran it through Adobe DNG converter, so maybe this helps for maximum compatibility.

https://drive.google.com/drive/folders/12c7fp5ymfV8YbmgA8p-otTZ6pk9Kp2U6?usp=sharing

Not a big user of DarkTable, but I have version 2.2.5 here and the file loads normal, and I can change exposure etc, so are you sure the download is right ?

escho

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Re: Mars
« Reply #29 on: July 29, 2018, 03:01:23 PM »
@Levas
Same problem with the new one. Only single_frame_processed.dng loads fine.
Using darktable 2.4.4 here. I will try a git-version of dt later in a VM
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escho

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Re: Mars
« Reply #30 on: July 29, 2018, 03:03:58 PM »
Single_frame_processed.dng is 4,4 MB
Stack 128_frames.dng only 715 kB
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Levas

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Re: Mars
« Reply #31 on: July 29, 2018, 03:16:45 PM »
Yeah I did notice the file size difference too.
Single frame is uncompressed DNG and the stacked frame is lossless compressed DNG (LJ92).
There's a lot of black in the frame, so the big size difference between compressed and uncompressed makes sense.
The 4,4 sized single frame becomes 1,4Mb when I use lossless compression with adobe DNG converter.
Still twice the size, but stacking 128 frames reduces a lot of the low light noise data, so that's probably it  ???

What file type are you using for stacking, like with the Mars and Saturn pictures, do you stack dng's or do you stack processed Tif files ?

Levas

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Re: Mars
« Reply #32 on: July 29, 2018, 03:22:32 PM »
@Escho
Now I think about it, maybe an uncompressed stack file works ?
Uploaded an uncompressed stack file, 4,7Mb in size:
https://drive.google.com/open?id=12c7fp5ymfV8YbmgA8p-otTZ6pk9Kp2U6

escho

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Re: Mars
« Reply #33 on: July 29, 2018, 03:47:28 PM »
It loads with the uncompressed dng. I think to remember that dattable doesnt like uncompressed tiffs very much. Maybe it´s the sam with dngs?

For the stacking job a use two szenarios:

1. Stacking MLVs
I use mlvapp to precess the files (get more contrast out of it). Than I export to uncompressed avi, which is 8 Bit. That´s what I stack with autostakkert. Than postprocessing with fitswork, darktable and gimp.

2. Stacking CR2s
For autostakkert (sun, moon, planets) I exort to 16 Bit uncompressed tiff.
For deepsky, I use CR2 for stacking or I preprocess with darktabe to tiff and stack than. (deepskystacker or preferred 9fitswork)
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g3gg0

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Re: Mars
« Reply #34 on: July 29, 2018, 06:03:33 PM »
Than I export to uncompressed avi, which is 8 Bit. That´s what I stack with autostakkert.

any reason why to switch to 8 bits alreary there? i directly used TIFF files to keep most information for autostakkert
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escho

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Re: Mars
« Reply #35 on: July 29, 2018, 08:08:57 PM »
any reason why to switch to 8 bits alreary there? i directly used TIFF files to keep most information for autostakkert
Yes, it´s by habbit :)
The old AS2 crashed in getting too much input. (on larger sequenzes on 16bit tiffs). AS3 doesnn´t crash here anymore. But I don´t see much difference in the reults for my planet-images in using 16bit vs. 8bit. So I use 8bit raw-asi for the stacking.
I don´t use mlv-files to get 16bit out (14bit). I use it to have a real 1:1 sensor crop for as much details as possible.
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