Arp 26 / M101 / Pinwheel Galaxy (Revisit, First Light)
| 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 | 2026-07-20 00:24:00 |
| Instrument | ZWO FF131 f7.5-983mm |
| Camera | ASI2600MC-Pro |
| Image Details | Up is 1.0 degrees E of N. Transparency: Fair. Seeing: Fair. Total integration time was 44m. Exposure 20s@150g, dithered 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. It's a more challenging object than you might think despite a nominal 7.9 apparent magnitude. The object is so large, nearly 1/2 degree in diameter, that the surface brightness is challengingly low. This was my first outing with the ZWO 131FF. I was pleased with the depth the 131FF could achieve with my one color camera in only 44m of integration. All prior were with an SCT. This was my second favorite observation overall. First was a July 2023 observation that revealed supernova SN 2023ixf, which had been discovered on May 13, 2023. You can see it in the "related" observations. |
| Related Observations | Arp026 (4) M101 (5) NGC5457 (4) |
| Catalog Links | <Previous | Messier Listings | Next> |
