| Name | Pinwheel Galaxy |
| Designation(s) | Arp 26, M 101, NGC 5457 |
| Object Type(s) | Galaxy |
| Relevant Catalog(s) | All (Chron), Arp, Messier, NGC |
| Arp Category | Spiral galaxies with one heavy arm |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Ursa Major |
| Date and Time Observed | 2025-03-18 22:53:00 |
| Instrument | EdgeHD 8" f10-2,032mm FL |
| Camera | ASI2600MC-Pro |
| Image Details | Up is 94.9 degrees E of N. Transparency: Fair. Seeing: Good. Total integration time was 40m. Exposure 20s@150g, Bin 2, UV/IR Cut Filter, captured in SharpCap. Hot and cold pixel removal in SharpCap. |
| Description | This is a Méchain discovery dated March 27, 1781. No formal recording date is noted for M101 nor for any remaining entries in the Catalog: "Nebula without star, very obscure & pretty large, of 6 or 7 minutes [of arc] in diameter, between the left hand of Bootes & the tail of the great Bear [Ursa Major]. It is difficult to distinguish when one lights the [graticule] wires." Halton Arp selected M101 for his Atlas of Peculiar Galaxies based on "one heavy arm" <--> This is a favorite target to which I've returned many times. Featured image is a recent capture with my new ASI2600mc-pro camera, my first outing with that camera and the EdgeHD. This was the same night as my recent capture of M81, but transparency had worsened. Fourth image in the gallery was a July 2023 observation (compared to yet another recent one) to show supernova SN 2023ixf, which had been discovered on May 13, 2023. |
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