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by 0x0203 360 days ago
Why do the brighter objects have the four way cross artifact? My (apparently incorrect) understanding was that those types of artifacts were a result of support structures holding reflecting mirrors on a telescope. But this camera just has a "standard" glass lense with nothing obstructing the light path to the sensor.
3 comments

Those diffraction spikes are caused by the four-vane spider structure supporting the secondary mirror in the telescope's optical path, not by the camera lenses themselves.
You are not wholly wrong! There is both a supporting structure for the mirror, AND a glass lens in front of the sensor to further flatten the incoming light.

The interesting thing about the spikes in our images is that they stay fixed in image plane coordinates, not sky coordinates. So as the night sky moves (earth rotates) the spikes rotate relative to the sky leading to a star burst pattern over multiple exposures.

It’s a reflecting telescope, not a camera with a glass lens.
Ah, thanks. I had seen a bunch of hype about the camera itself (which is on its own very impressive) and assumed that was the complete device. Didn't realize it was part of a larger telescope.