Author Topic: Stacking subsets the same as stacking all frames at once?  (Read 988 times)

Offline chrisvdberge

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When I have many frames (80+) I might come in trouble with the Integration process, running out of memory.
Sometimes I see the advice to just subdivide the total sets in equal sized subsets, and then integrate those subsets.
However, I'm not sure if this will give exactly the same result? The pixel rejection might work differently, or is this not a factor if you keep the subsets big enough? (30+)

I'm currently trying to make a masterBias, that's why I have so many files to integrate ;)

Offline Zocky

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Re: Stacking subsets the same as stacking all frames at once?
« Reply #1 on: 2015 June 28 02:25:49 »
Do you use 32 bit or 64 bit version of PI? How much memory do you have?
I have 4 GB old machine and I never had a problem with creating master calibration frames (usually I use set with 100 frames).
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline chrisvdberge

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Re: Stacking subsets the same as stacking all frames at once?
« Reply #2 on: 2015 June 28 05:07:41 »
I'm using 64 bit. I have a macbook with 16GB of RAM and SSD, so wouldn't assume that is a problem.
When I convert the RAW files to FIT's first, I get a read error on the 252th file. Tried it with rebooting, retaking the pictures and even a complete different set of images from a different camera.
I guess using 250 files and then using SuperBias will give me a good result, but this made me wonder if stacking to substacks would be the same thing as stacking everything in 1 go.

Offline msmythers

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Re: Stacking subsets the same as stacking all frames at once?
« Reply #3 on: 2015 June 28 08:49:04 »
This is an old OSX issue. See these postings. The last postiong listed seems the most promising from what I've read. I don't run OSX so I haven't tried.
http://pixinsight.com/forum/index.php?topic=5177.msg35654#msg35654
http://pixinsight.com/forum/index.php?topic=6871.msg46485#msg46485
http://pixinsight.com/forum/index.php?topic=6881.msg55916#msg55916


Mike