More than astrophotography, an astronomical exploration.
The heart of the Lion
David Cruz · Astromidnight
Regulus, the heart of Leo, shines just 79 light-years away, with the telescope's diffraction spikes. Beside it, the faint smudge is Leo I, a small satellite galaxy of the Milky Way about 10,000 times farther away.
| Catalogue | α Leonis · HR 3982 · HD 87901 |
| Type | B-type star and dwarf spheroidal galaxy |
| Distance | ≈ 79 light-years (Regulus) · ≈ 800,000 light-years (Leo I) |
| Field | 115.1′ × 72.8′ |
| Scale | 1.11″ / pixel |
| Orientation | −98° · west up |
| RA (centre) | 10h 08m 18s |
| DEC (centre) | +12° 04′ 37″ |
| Constellation | Leo |
| Objects in field | Regulus A and B · Leo I · IC 591 · 2 background galaxies, 1 cluster and 1 quasar |
Distances of Regulus and Leo I according to NASA's APOD (2024); the tip of the red giant branch measurement gives 254 kpc for Leo I, about 830,000 light-years (Bellazzini et al. 2004). The distances of IC 591, Z 64-80, the cluster and the quasar were estimated from the SIMBAD redshift (H0 = 70 km/s/Mpc; for large z, light travel time in a standard cosmological model). No real width: the objects are at very different distances. Positions of all objects taken from SIMBAD.
4 h 40 min of light
Each tick is a 240-second exposure. 70 in total, with the camera at −10 °C and gain 100. Calibrated with 50 darks, 50 flats and 50 bias. The Moon stayed below 90 % 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
Adobe Photoshop · Pleiades Astrophoto PixInsight · ZWO ASIAIR
São Pedro da Gafanhoeira, Évora · 358 m
Bortle 3