NGC 2903
UGC 5079 · Galaxy in Leo
- Magnitude
- 9.0
- Size
- 12.6′ × 6′
- Effective surface brightness
- 22.3 mag/arcsec²
- Best months
- Jan, Feb, Mar
- Declination
- +22°
- Filter
- None (broadband target)
A bright barred spiral below the Sickle of Leo that Messier somehow missed. Bright core, well-defined arms.
Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
How long with each smart telescope
| Telescope | In frame | Bortle 3 (rural) | Bortle 5 (suburban) | Bortle 7 (urban edge) |
|---|---|---|---|---|
| ZWO Seestar S5010 s subs | 29% | 54 min322 subs | 1 h 29 min532 subs | 4 h 01 min1,448 subs |
| ZWO Seestar S50 Pro10 s subs | 15% | 1 h359 subs | 1 h 37 min585 subs | 4 h 23 min1,577 subs |
| ZWO Seestar S3010 s subs | 18% | 1 h 01 min365 subs | 1 h 36 min575 subs | 4 h 08 min1,491 subs |
| ZWO Seestar S30 Pro10 s subs | 9% | 1 h 04 min385 subs | 1 h 44 min623 subs | 4 h 38 min1,666 subs |
| DwarfLab DWARF 315 s subs | 13% | 1 h 10 min279 subs | 2 h 04 min495 subs | 6 h1,439 subs |
| DwarfLab DWARF mini15 s subs | 18% | 53 min212 subs | 1 h 28 min352 subs | 4 h 01 min963 subs |
| DwarfLab Draco30 s subs | 17% | 43 min86 subs | 1 h 12 min144 subs | 3 h 19 min399 subs |
| DwarfLab DWARF II15 s subs | 12% | 4 h 01 min964 subs | 5 h 38 min1,352 subs | 13 h3,049 subs |
| Vaonis Vespera II10 s subs | 15% | 54 min322 subs | 1 h 29 min532 subs | 4 h 01 min1,448 subs |
| Vaonis Vespera Pro10 s subs | 13% | 2 h 12 min793 subs | 3 h 26 min1,234 subs | 8 h 47 min3,161 subs |
| Vaonis Vespera 310 s subs | 14% | 51 min305 subs | 1 h 24 min506 subs | 3 h 51 min1,386 subs |
| Vaonis Vespera Pro 210 s subs | 13% | 2 h 05 min748 subs | 3 h 15 min1,172 subs | 8 h 24 min3,022 subs |
| Unistellar eQuinox 24 s subs | 37% | 1 h 14 min1,110 subs | 1 h 36 min1,436 subs | 3 h 11 min2,865 subs |
| Unistellar Odyssey4 s subs | 37% | 6 h 37 min5,954 subs | 7 h 56 min7,143 subs | 14 h12,339 subs |
| Celestron Origin10 s subs | 25% | 12 min75 subs | 22 min135 subs | 1 h 06 min395 subs |
| Celestron Origin Mark II10 s subs | 28% | 15 min93 subs | 30 min179 subs | 1 h 32 min553 subs |
Imaging the galaxy
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
Per-telescope pages
- How long to image the NGC 2903 with the ZWO Seestar S50
- How long to image the NGC 2903 with the ZWO Seestar S50 Pro
- How long to image the NGC 2903 with the ZWO Seestar S30
- How long to image the NGC 2903 with the ZWO Seestar S30 Pro
- How long to image the NGC 2903 with the DwarfLab DWARF 3
- How long to image the NGC 2903 with the DwarfLab DWARF mini
- How long to image the NGC 2903 with the DwarfLab Draco
- How long to image the NGC 2903 with the DwarfLab DWARF II
- How long to image the NGC 2903 with the Vaonis Vespera II
- How long to image the NGC 2903 with the Vaonis Vespera Pro
- How long to image the NGC 2903 with the Vaonis Vespera 3
- How long to image the NGC 2903 with the Vaonis Vespera Pro 2
- How long to image the NGC 2903 with the Unistellar eQuinox 2
- How long to image the NGC 2903 with the Unistellar Odyssey
- How long to image the NGC 2903 with the Celestron Origin
- How long to image the NGC 2903 with the Celestron Origin Mark II