thanks for the links, that's really interesting to look at

do you happen to know how exactly those artifacts are cleaned up?

icegreentea2 4 hours ago | parent | next [-]

The blog link describes the cleanup process.

They take two pictures, each taking up half the total observation period. If you subtract the two images, the deltas should be the cosmic ray flashes. You can then subtract those out. They use two pictures as opposed to more to minimize the impact of readout noise.

To deal with "stuck pixel" type errors, they can slightly shift the camera between the two observations. They can counter act the shift before doing the initial subtraction.

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srean 2 hours ago | parent | next [-]

Signal processing / denoising of astronomical images is a field of study onto itself.

If you are like me you will find it super interesting. There is immense variety based upon what kind of telescope, what do you want to capture, whether it's for science or astrophotography (aesthetics).

If you are into math side of things you can begin with Richardson-Lucy as a starting point and stacking.

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empiricus 3 hours ago | parent | prev [-]

funny how this also eliminates "close" fast moving objects. which I guess is a feature for a telescope

	▲	empiricus 3 hours ago \| parent [-]
		I mean funny in the sense of "we did not find any anomalies, because we are careful to filter them out"

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shrubble 5 hours ago | parent | prev | next [-]

One way is to take a “blank” picture which will then show just the noise; then use that as a reference for what can be removed from the image.

	▲	rbanffy 5 hours ago \| parent [-]
		The blank should only show long term damage. Hits while the sensor is collecting light can be averaged out from multiple readings of the sensor.

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javier2 4 hours ago | parent | prev | next [-]

its actually quite doable. any cosmic rays will not be present in two pictures in a row. any permanent damage will be exactly the same in all pictures.

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lofaszvanitt 5 hours ago | parent | prev [-]

photoshop ;D, or using multiple pictures