More than astrophotography, an astronomical exploration.
Dual Spirals in Canes Venatici
David Cruz · Astromidnight
In Canes Venatici, two spirals share the field: NGC 4151, the "Eye of Sauron", and NGC 4145. At the centre of the first, an active supermassive black hole makes the nucleus shine.
| Catalogue | New General Catalogue, 1888 · NGC 4151 |
| Type | Seyfert spiral galaxy |
| Distance | ≈ 52 million light-years |
| Field | 52.0′ × 33.7′ |
| Scale | 0.41″ / pixel |
| Orientation | 88° · east up |
| RA (centre) | 12h 10m 18s |
| DEC (centre) | +39° 38′ 10″ |
| Constellation | Canes Venatici |
| Objects in field | NGC 4151 · NGC 4145 · NGC 4156 · 2 galaxy clusters |
Distance of NGC 4151 from Cepheids (Yuan et al. 2020); that of NGC 4145 is the median of the Tully-Fisher estimates in NED, with a large spread (9 to 22 Mpc). The distances of the background galaxies and the light travel times of the clusters were calculated from the SIMBAD redshift (H0 = 70, flat cosmology). There is no real width: the field mixes objects at very different distances. Coordinates from SIMBAD; the positions in the image were adjusted by hand because the astrometry.net solution is rotated 180° relative to the published image.
16 h 56 min of light
Each tick is a 240-second exposure. 254 in total, with the camera at −10 °C and gain 100. Calibrated with 30 darks, 30 flats and 30 bias. The Moon stayed below 20 % illumination throughout.
Carbon Newton 10' f/4
ZWO ASI2600MC Pro
Twinstar Friction Mount FG80
Askar M54 OAG · ZWO ASI120MM Mini
TS-Optics Maxfield .95X Coma Corrector
Adobe Photoshop · Pleiades Astrophoto PixInsight · Stefan Berg Nighttime Imaging 'N' Astronomy (N.I.N.A. / NINA)
São Pedro da Gafanhoeira, Évora · 358 m
Bortle 3