More than astrophotography, an astronomical exploration.
Little Pinwheel Galaxy
David Cruz · Astromidnight
In Ursa Major, the Little Pinwheel Galaxy shows us its arms face-on, 47 million light-years away. Beside it, the orange star Tania Australis shines much closer, just 230 light-years away.
| Catalogue | New General Catalogue, 1888 · NGC 3184 · UGC 5557 |
| Type | Spiral galaxy |
| Distance | ≈ 47 million light-years |
| Field | 116.4′ × 76.5′ |
| Scale | 1.35″ / pixel |
| Orientation | −145° · south-west up |
| RA (centre) | 10h 20m 55s |
| DEC (centre) | +41° 26′ 32″ |
| Constellation | Ursa Major |
| Objects in field | NGC 3184 · NGC 3179 · Abell 971 · Tania Australis · 1 quasar |
Distance of NGC 3184 adopted by Hosseinzadeh et al. (2018), 14.4 ± 0.3 Mpc; the size of the galaxy in light-years was calculated by us from its apparent diameter (SIMBAD). Distances of NGC 3179 and Abell 971 calculated from redshift, with H0 = 70 km/s/Mpc; the light travel time of the quasar was calculated by us (H0 = 70, Ωm = 0.3). Distance of Tania Australis from the Hipparcos parallax (the Gaia DR3 one is unreliable for this star, RUWE 3.3); the other stars from the Gaia DR3 parallax. No real width: the field mixes stars in our galaxy with galaxies at very different distances. All positions from SIMBAD or NED.
8 h 00 min of light
Each tick is a 240-second exposure. 120 in total, with the camera at −10 °C and gain 100. Calibrated with 50 darks, 50 flats and 50 bias. The Moon stayed below 100 % illumination throughout.
TS-Optics 150mm/6" ONTC f/4 Newtonian (carbon tube)
ZWO ASI2600MC Pro
ZWO AM5
ZWO ASI120MM Mini
TS-Optics Maxfield .95X Coma Corrector · ZWO EAF · ZWO Manual filter wheel 5 x 1.25"
Aries Productions Astro Pixel Processor (APP) · Pleiades Astrophoto PixInsight · ZWO ASIAIR
São Pedro da Gafanhoeira, Évora · 358 m
Bortle 3