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!
> 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.
Why does the technique not work with aircraft? Because they generally fly on fixed routes?
This time-lapse probably better visualizes it: https://www.youtube.com/watch?v=wFpeM3fxJoQ
Maybe for some close stars parallax might work to remove them over the course of half a year. But no way could the Earth's rotation during a single night move background stars out of a nebulae.
Don't forget that not only does the star need to be removed, but also the diffraction spikes. Those are internal reflections in the lens assembly - not mapped by any star catalog ))
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 have yet to see a precise technical definition of what "generative AI" means, but StarXTerminator uses a neural network that generates new data to fill in the gaps where non-stellar objects are obscured by stars. And it advertises itself as "AI powered".
But that's very different to saying that no generative AI was used at all in their production. "AI augmented" sounds pretty accurate to me.
Likewise, if someone posted a photo taken with their iPhone where they had used the built-in AI features to (for instance) remove people or objects, and then they claimed that no AI was involved, I would consider that misleading, even if the photo accurately depicts a real scene in other respects.
https://astrobackyard.com/starnet-astrophotography/
“StarNet is a neural network that can remove stars from images in one simple step leaving only the background. More technically, it is a convolutional residual net with encoder-decoder architecture and with L1, Adversarial and Perceptual losses.”
> So these are more artistic photo works than real science photos...
I agree that the claim "no generative AI used" is technically incorrect, but I do feel that the image does not contain any AI-hallucinated content and therefore is an accurate representation of reality. These structures appear in the image exactly as they exist in nature.