Features in the Gallery: Very Bright Stars

Lots of people are using the Image gallery. One popular theme is to find images that look very peculiar. E.g., look at the image in the gallery from 2008-11-29 19:02:44

Gallery: 2008-11-29 19:02:44

This is a very peculiar looking field in the DSS. It looks very pixelated, but it’s a normal sized image so the pixels are much larger than the actual image pixels. There are few if any stars visible? What’s going on?

We can find out by zooming out and doing a full square degree region around the same center: 101.35626366727445,-16.713875539779025. This gives us the image we see at 2008-12-01 16:59:43 in the gallery.

Gallery: 2008-12-01 16:59:43

The image is actually the center of a massive burnt out region in the underlying photographic plate. We’re looking at Sirius! A big (40″) telescope, extremely sensitive emulsion and long exposure don’t mix well with the brightest star in the sky. The scattered light from Sirius is still affecting the data over this entire square degree but at least at this scale we can see the cause and at the edges we can begin to pick up other objects in the field. So don’t expect to see very bright stars in most of the optical surveys. They are a billion times brighter than the objects that these surveys were intended to detect.

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