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wowsosquare t1_itigqkw wrote

Reply to comment by Riegel_Haribo in James Webb revisited gravitational-lensing cluster Abell 2744 this week - and I spent hours processing and cleaning hundreds of cosmic ray artifacts to reveal the faintest details, yet unseen, in glorious six-color 4k+ by Riegel_Haribo

AMAZING... and I never thought about cosmic rays and the space telescopes. Now that I think about it, how do we get any of these great pictures, given that the telescopes and their sensors are constantly being blasted with these high energy particles

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Riegel_Haribo OP t1_itj4tby wrote

They could certainly be handled better than they currently are in STScI pipeline processing. Here is just one filter of this observation: an area with full coverage of the four dithers, made of exposures with ten integration groups each... and we still get the halo rings of poorly-removed "snowballs" peppering our picture:

https://i.imgur.com/aVEQDWB.jpg

Now overlay six layers of that.

And here's an animated GIF of the exposures that make up a dithering, with the constant sparkles and some incidental streaks of lower energy cosmic rays that should have been cleaned by earlier ramp jump detection, becoming a background noise:

https://i.imgur.com/lE8Yqyl.gif

You can see some of this in a square at the center of the left edge of the Abell image with low dither coverage.

In the last frame of the GIF, see both a "removed" snowball in the middle, and an unremoved blob at the lower edge.

The solution is many more shorter dither observations, and processing that takes a comprehensive start-to-end removal strategy.

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wowsosquare t1_itk0jkk wrote

W9ow I didn't know so much thought went into making these!

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Alien_Fruit t1_itk5qg2 wrote

I was just about to say the same thing! It must be an exhausting job, cleaning up these images! But the result is fantissimo!

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