alt Hacker NewsI'm curious how the starless versions are created. From the steps at the end, I couldn't see a 'this is how stars are removed' step. Maybe it's part of stacking (but most stars would remain present?) or the calibration process treating stars as noise?
Replies
>> I'm curious how the starless versions are created.
Its done with using dedicated astrophotography software (StarXTerminator). Example: https://astrobackyard.com/starnet-astrophotography/
So these are more artistic photo works than real science photos...
Rod Prazeres the Astrophotographer, has given this interview where he talks about the process: https://www.astronomy.com/observing/the-astrophotography-of-...
I feel like the stars are probably pretty easy to mask out since they’re very bright relative to the rest of the image. Once you have the mask, each one is small enough that you could probably fill it with the values from adjacent pixels. Kinda like sensor mapping to hide dead pixels. That’s just a guess though, I’m sure there’s more to it than that.
Traditionally (pre-ai) you would use another image of the same part of the sky and negate the items that you want to remove from the image
As an example terrestrial telescope mirrors get dusty. You're not going to break down the scope just to clean up the dust as this is a many days operation in most cases. So instead you would take "flats" that were of a pure white background and thus showed the dust in its full, dusty, glory. When you take your actual images, you negate (subtract from the original image) the flat and thus any noise generated by the dust. You can use this same method for removing brighter stars from an image that would otherwise saturate the ccd and wash out the background. Turns out it doesn't work for planes. Ask me how I know!