How long to image the Fireworks Galaxy with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 11 h (4,047 subs of 10 s) for a solid image of the Fireworks Galaxy. A quick look takes 2 h 49 min; a showpiece 45 h. Under a Bortle 3 rural sky the solid figure drops to 4 h 30 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 11% 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 | 58 min347 subs | 3 h 51 min1,386 subs | 15 h5,542 subs |
| Bortle 2Typical dark site | 1 h 01 min367 subs | 4 h 05 min1,468 subs | 16 h5,869 subs |
| Bortle 3Rural | 1 h 08 min406 subs | 4 h 30 min1,622 subs | 18 h6,487 subs |
| Bortle 4Rural / suburban transition | 1 h 23 min500 subs | 5 h 33 min1,997 subs | 22 h7,986 subs |
| Bortle 5Suburban | 1 h 48 min648 subs | 7 h 12 min2,590 subs | 29 h10,360 subs |
| Bortle 6Bright suburban | 2 h 49 min1,012 subs | 11 h4,047 subs | 45 h16,186 subs |
| Bortle 7Suburban / urban transition | 4 h 44 min1,706 subs | 19 h6,822 subs | 76 h27,287 subs |
| Bortle 8City | 7 h 44 min2,783 subs | 31 h11,131 subs | 120+ h44,522 subs |
| Bortle 9Inner city | 14 h5,080 subs | 56 h20,320 subs | 230+ h81,280 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 15 h of run time. That is more than one night: over 3 nights, about 4 h 52 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.)
- 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 Fireworks Galaxy is 11′ × 10′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 11% 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 | 4 h 30 min1,622 subs | 7 h 12 min2,590 subs | 19 h6,822 subs |
| 20 s | 3 h 41 min665 subs | 6 h 23 min1,149 subs | 18 h3,265 subs |
| 30 s | 3 h 25 min411 subs | 6 h 07 min734 subs | 18 h2,144 subs |
About the Fireworks Galaxy
A face-on spiral famous for its supernovae, dimmed by Milky Way dust. Faint arms; the open cluster NGC 6939 sits nearby.
NGC 6946, Caldwell 12 · Galaxy in Cygnus · magnitude 9.6 · 11′ × 10′ · best in Jul, Aug, Sep. 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 Fireworks 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
- Fireworks Galaxy with the ZWO Seestar S50: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S50 Pro: 5 h 45 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S30: 5 h 32 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S30 Pro: 6 h 06 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF 3: 7 h 37 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF mini: 5 h 14 min from Bortle 6
- Fireworks Galaxy with the DwarfLab Draco: 4 h 19 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF II: 18 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera II: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro: 12 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera 3: 5 h 01 min from Bortle 6
- Fireworks Galaxy with the Unistellar eQuinox 2: 4 h 49 min from Bortle 6
- Fireworks Galaxy with the Unistellar Odyssey: 22 h from Bortle 6
- Fireworks Galaxy with the Celestron Origin: 1 h 23 min from Bortle 6
- Fireworks Galaxy with the Celestron Origin Mark II: 1 h 54 min from Bortle 6
All telescopes for the Fireworks Galaxy · All targets for the Vespera Pro 2