2 purple blogs


You know I haven’t looked in here in a long time, and I did today and saw something I’ve not seen before: 2 purple blobs. Is this a thing?

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Must be. I poked around and found a couple more. Perhaps they are artifacts? There are bright objects nearby.


This is an asteroid. They appear like this in HSC.

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Try looking at it in DR 10

What do you think - artifact or object?

Very likely an asteroid. They appear as mono-color / single band colored because they are only observed in one exposure (through one filter) and then they move. In this case, it looks like two exposures nearby in time, maybe within a few minutes, in the “g” filter that is shown as blue in these RGB images. The upper one looks elongated in the direction of motion, as you’d expect.

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