How long to image the Whale Galaxy with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 1 h 56 min (698 subs of 10 s) for a solid image of the Whale Galaxy. A quick look takes 29 min; a showpiece 7 h 45 min. Under a Bortle 3 rural sky the solid figure drops to 50 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 16% 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 | 11 min67 subs | 44 min265 subs | 2 h 56 min1,057 subs |
| Bortle 2Typical dark site | 12 min70 subs | 46 min278 subs | 3 h 05 min1,110 subs |
| Bortle 3Rural | 13 min76 subs | 50 min303 subs | 3 h 22 min1,211 subs |
| Bortle 4Rural / suburban transition | 15 min91 subs | 1 h 01 min364 subs | 4 h 02 min1,455 subs |
| Bortle 5Suburban | 19 min116 subs | 1 h 17 min461 subs | 5 h 07 min1,841 subs |
| Bortle 6Bright suburban | 29 min175 subs | 1 h 56 min698 subs | 7 h 45 min2,789 subs |
| Bortle 7Suburban / urban transition | 48 min288 subs | 3 h 11 min1,149 subs | 13 h4,596 subs |
| Bortle 8City | 1 h 17 min463 subs | 5 h 08 min1,851 subs | 21 h7,401 subs |
| Bortle 9Inner city | 2 h 19 min837 subs | 9 h 18 min3,346 subs | 37 h13,382 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 31 min of run time. The Vespera Pro 2’s battery (rated about 11 h) should cover it; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time.)
- 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.
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How it frames
The Whale Galaxy is 15.5′ × 2.7′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 16% 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 | 50 min303 subs | 1 h 17 min461 subs | 3 h 11 min1,149 subs |
| 20 s | 42 min128 subs | 1 h 09 min207 subs | 3 h 04 min551 subs |
| 30 s | 40 min80 subs | 1 h 06 min133 subs | 3 h 01 min362 subs |
About the Whale Galaxy
A distorted edge-on galaxy with a small companion on its back, and the Hockey Stick (NGC 4656) in the same wide field.
NGC 4631, Caldwell 32 · Galaxy in Canes Venatici · magnitude 9.2 · 15.5′ × 2.7′ · best in Mar, Apr, May. 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 Whale Galaxy 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
- Whale Galaxy with the ZWO Seestar S50: 55 min from Bortle 6
- Whale Galaxy with the ZWO Seestar S50 Pro: 1 h from Bortle 6
- Whale Galaxy with the ZWO Seestar S30: 57 min from Bortle 6
- Whale Galaxy with the ZWO Seestar S30 Pro: 1 h 03 min from Bortle 6
- Whale Galaxy with the DwarfLab DWARF 3: 1 h 19 min from Bortle 6
- Whale Galaxy with the DwarfLab DWARF mini: 54 min from Bortle 6
- Whale Galaxy with the DwarfLab Draco: 45 min from Bortle 6
- Whale Galaxy with the DwarfLab DWARF II: 3 h 06 min from Bortle 6
- Whale Galaxy with the Vaonis Vespera II: 55 min from Bortle 6
- Whale Galaxy with the Vaonis Vespera Pro: 2 h 02 min from Bortle 6
- Whale Galaxy with the Vaonis Vespera 3: 52 min from Bortle 6
- Whale Galaxy with the Unistellar eQuinox 2: 49 min from Bortle 6
- Whale Galaxy with the Unistellar Odyssey: 3 h 46 min from Bortle 6
- Whale Galaxy with the Celestron Origin: 14 min from Bortle 6
- Whale Galaxy with the Celestron Origin Mark II: 20 min from Bortle 6
All telescopes for the Whale Galaxy · All targets for the Vespera Pro 2