30 December 2022 at 6:47 pm #614908
I observed a number of VS on 2020-02-01/02, including U Leo which is at 10:24:03.81, +14:00:25.9. A good time series was acquired.
Just before that, I slewed to the general direction and took a few snapshots so that the plate solving software could refine the mount’s pointing model and, sure enough, the model wasn’t quite good enough, with a plate centre of 10:24:19.92, +13:57:56.7. Sure enough, the intended FOV needed to be refined but I kept the subs anyway, for posterity (not that posterity has ever done anything for me) in the chance they may prove interesting and/or useful.
The subs, five of them with a total exposure of 150 seconds, have only just been examined with a critical eye. They contain an object which does not appear in the DSS2 images. Nothing brighter than V=19.2 is known to the MPC for that position at the time. A few U Leo comparisons are in-shot and a rough estimate shows the object appears to be V=15.7 to 16.0. Its position at 23:11 UTC was measured as 10:24:26.25 +13:58:41.3
Anyone any idea what it may have been? I don’t, as yet.
Added in edit. Gaia EDR-3 3887276836916920448 is about 10″ away at 10:24:25.784, 13:58:49.34, but is catalogued at g=20.4 so unless it is a flare star, and an impressive one at that, it seems unlikely to be related given its distance. To be fair, that has b=21.1 and r=19.2 so could be a red dwarf I suppose.
Full data, including the original subs in FITS format, can be provided on request.
30 December 2022 at 6:54 pm #614909Grant PrivettParticipant
- This topic was modified 1 month ago by Dr Paul Leyland.
You are near the ecliptic. I assume you checked for a transiting asteroid?30 December 2022 at 6:57 pm #614911
Yup. As I said, the MPC knows nothing. The nearest is (102550) 1999 UY1, several arcminutes away and V=19.231 December 2022 at 4:00 pm #614915Grant PrivettParticipant
My mistake re: MPC.
Is there anything there on any night since?1 January 2023 at 12:43 pm #614930
My mistake too — the object is (102550) 1999 UY17 — I failed to cut and paste the final digit.
I need to check other images of U Leo (there are hundreds) but most of them are properly centred and unlikely to show the region well.
When I return to LP more images can be taken; deeper too. If it is a star it’s quite likely to be brighter than 22.0 at minimum.
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