How long to image the NGC 2403 with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 3 h 13 min (1,161 subs of 10 s) for a solid image of the NGC 2403. A quick look takes 48 min; a showpiece 13 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 11 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 24% 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 | 15 min90 subs | 59 min357 subs | 3 h 58 min1,427 subs |
| Bortle 2Typical dark site | 16 min96 subs | 1 h 04 min382 subs | 4 h 14 min1,526 subs |
| Bortle 3Rural | 18 min108 subs | 1 h 11 min429 subs | 4 h 45 min1,713 subs |
| Bortle 4Rural / suburban transition | 23 min136 subs | 1 h 30 min542 subs | 6 h 01 min2,165 subs |
| Bortle 5Suburban | 30 min181 subs | 2 h721 subs | 8 h2,883 subs |
| Bortle 6Bright suburban | 48 min291 subs | 3 h 13 min1,161 subs | 13 h4,642 subs |
| Bortle 7Suburban / urban transition | 1 h 23 min500 subs | 5 h 33 min1,999 subs | 22 h7,996 subs |
| Bortle 8City | 2 h 18 min826 subs | 9 h 10 min3,301 subs | 37 h13,202 subs |
| Bortle 9Inner city | 4 h 13 min1,520 subs | 17 h6,077 subs | 68 h24,306 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 11 min of run time. The Vespera II’s battery is rated at about 4 h, less near freezing, so the session needs an external power bank. (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 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
- Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
- 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.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the Vespera II →
How it frames
The NGC 2403 is 21′ × 12′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 24% 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, no EQ mode. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 1 h 11 min429 subs | 2 h721 subs | 5 h 33 min1,999 subs |
| 20 s | 1 h180 subs | 1 h 49 min327 subs | 5 h 22 min966 subs |
| 30 s | 56 min113 subs | 1 h 45 min210 subs | 5 h 18 min636 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 II
A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted.
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 II? 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 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 Vaonis Vespera Pro 2: 6 h 53 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 II