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Simple image processing of images from PD video camera using rotation and despeckling  GIMP software

Roger Samworth



Given that some of the summer meetings topics is image processing, and given that it is raining, and I wanted to do something astronomical, I thought the group might be interested in the attached sequence processed in GIMP (current version of GIMP is 2.8

You have to appreciate that my expertise is limited to the "Press that button and see what happens" variety!

Firstly, there is the PD image of the North America Nebula I sent the other day, which is itself a composite of 2 exposures.

Then, I rotated it, cropped it and re-sized it to 640 X 480. The original 640 X 400 resolution was now down to about half that.The stars are very "blobby", due to the poor resolution and exposure.

Then I used the "despeckle" option in GIMP to suppress the stars and emphasise the nebulosity.

Now you can compare it to this image at

I have also attached a jpg of that image.

You can at least make out North America and the Pelican! Not as good, of course, but fun, given the equipment and the acquisition time (about 50 sec in total)!



NGC 7000/C14 original image from PD video camera (below)

ngc 7000-c14

NGC 7000/C14 despeckled (below)

15-07-09 ngc 7000-c14 rotated

NGC 7000/C14 despeckled & rotated (below)

15-07-09 ngc 7000-c14 rotated despec2

Comparison image from (below):

nam on www
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