first real stacking success!

Wow does it feel great to have some modicum of success in learning how to stack images.


  • Keith’s Image Stacker
  • 30 second, 1920×1080 .mov file captured with Nikon D7000, May 10, 2012, 10:35:11pm, David Dunlap Observatory .75 focal reducer [same night as images from this post]
  • 175 hand-picked frames.

I went through some trial and error getting Keith’s working. The first image I ever imported was something like 240px wide, and every image thereafter opened at the same dimensions. I trashed the prefs [instead of re-installing] and this allowed me to open the larger files at the correct dimensions. So: in the documentation where Keith notes that the image dimensions will be those of the first file you open, this doesn’t mean per session, it means ever. Computer>Library>Preferences….

Then, when importing, with 1 and 2 threads, Keith’s would hang up at some point. Thanks to John’s computing prowess, I manually imported, and when I hit 175 frames, the software hung up again. I guess that’s the limit for this software. I started over and selected the best 175 frames I could discern in that tiny import frame [previewing the video helped me to confirm a roundabout set of frames, at 24fps].

I identified and selected my best reference frame, and did a Difference Sort – nothing seemed to happen. Then I did a Value Range sort – nothing seemed to happen. So I went ahead and stacked all 175 frames.

I saved as a PICT file [311KB, won’t work for the MacKenzie install], and also exported as 3-channel FITS, and as RAW.

To open RAW in Photoshop: input the export data, use IBM/PC byte order [not mac!], and do not colour manage.

Photoshop won’t recognize FITS format on its own, and a quick web search lead me to this site, where I downloaded the awesomely named FITS Liberator for mac. Of course, it only supports CS3 and CS4, and I have CS5.

Here is a .jpg from the raw file [via .psd, Adobe RGB (1998)].

©Risa Horowitz 2012

first successful stack. no post-processing outside of alignment and stacking.

Tomorrow night I’ll export some tests with fewer frames, and prepare some files for output tests to vinyl in preparation for the MacKenzie Art Gallery faculty-wide exhibition we are installing at the end of the month [curated by the most wonderful Jeff Nye]. More blogging will follow….
Addition, 8 November, 2012. I did a bit of post-processing, here’s a sample from a 22-frame stack of the best frames from those 175 original selected:

22 frames stacked from the 175, some post-processing

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