How long to image the NGC 2403 with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 6 h 53 min (2,481 subs of 10 s) for a solid image of the NGC 2403. A quick look takes 1 h 43 min; a showpiece 28 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 47 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it fills 21% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 36 min215 subs | 2 h 23 min858 subs | 9 h 32 min3,431 subs |
| Bortle 2Typical dark site | 38 min227 subs | 2 h 31 min908 subs | 10 h3,630 subs |
| Bortle 3Rural | 42 min251 subs | 2 h 47 min1,002 subs | 11 h4,007 subs |
| Bortle 4Rural / suburban transition | 51 min308 subs | 3 h 25 min1,231 subs | 14 h4,921 subs |
| Bortle 5Suburban | 1 h 06 min399 subs | 4 h 25 min1,593 subs | 18 h6,369 subs |
| Bortle 6Bright suburban | 1 h 43 min621 subs | 6 h 53 min2,481 subs | 28 h9,923 subs |
| Bortle 7Suburban / urban transition | 2 h 54 min1,044 subs | 12 h4,174 subs | 46 h16,694 subs |
| Bortle 8City | 4 h 43 min1,701 subs | 19 h6,802 subs | 76 h27,207 subs |
| Bortle 9Inner city | 8 h 37 min3,102 subs | 34 h12,407 subs | 140+ h49,628 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 8 h 57 min of run time. That is more than one night: over 2 nights, about 4 h 29 min each. The Vespera Pro 2’s battery (rated about 11 h) should cover each night; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a January night.)
- USB-C PD power bank 20000mAh 30WExternal bank extends the 11 h battery.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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How it frames
The NGC 2403 is 21′ × 12′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 21% of the frame’s short side.
Longer subs
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 2 h 47 min1,002 subs | 4 h 25 min1,593 subs | 12 h4,174 subs |
| 20 s | 2 h 17 min412 subs | 3 h 56 min707 subs | 11 h1,998 subs |
| 30 s | 2 h 07 min255 subs | 3 h 46 min452 subs | 11 h1,312 subs |
About the NGC 2403
A big, loose spiral in Camelopardalis that looks like a small M33, with bright H II regions dual-band can pick out.
Caldwell 7 · Galaxy in Camelopardalis · magnitude 8.9 · 21′ × 12′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
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.
About the Vaonis Vespera Pro 2
The square-sensor 2026 Vespera with 2 µm pixels. Sharper than the Vespera 3 on small targets and correspondingly slower per pixel; the 12.5 MP square frame suits galaxies and planetaries.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 10 s and 30 s subs is small; from a rural site it can halve the total time, especially with a dual-band filter in place.
Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.
Have an image of the NGC 2403 from a Vespera Pro 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- NGC 2403 with the ZWO Seestar S50: 3 h 13 min from Bortle 6
- NGC 2403 with the ZWO Seestar S50 Pro: 3 h 32 min from Bortle 6
- NGC 2403 with the ZWO Seestar S30: 3 h 23 min from Bortle 6
- NGC 2403 with the ZWO Seestar S30 Pro: 3 h 44 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF 3: 4 h 40 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF mini: 3 h 13 min from Bortle 6
- NGC 2403 with the DwarfLab Draco: 2 h 39 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF II: 11 h from Bortle 6
- NGC 2403 with the Vaonis Vespera II: 3 h 13 min from Bortle 6
- NGC 2403 with the Vaonis Vespera Pro: 7 h 14 min from Bortle 6
- NGC 2403 with the Vaonis Vespera 3: 3 h 05 min from Bortle 6
- NGC 2403 with the Unistellar eQuinox 2: 2 h 57 min from Bortle 6
- NGC 2403 with the Unistellar Odyssey: 14 h from Bortle 6
- NGC 2403 with the Celestron Origin: 51 min from Bortle 6
- NGC 2403 with the Celestron Origin Mark II: 1 h 10 min from Bortle 6
All telescopes for the NGC 2403 · All targets for the Vespera Pro 2