How long to image the Fireworks Galaxy with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 12 h (4,247 subs of 10 s) for a solid image of the Fireworks Galaxy. A quick look takes 2 h 57 min; a showpiece 47 h. Under a Bortle 3 rural sky the solid figure drops to 4 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 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 | 1 h 01 min369 subs | 4 h 06 min1,476 subs | 16 h5,903 subs |
| Bortle 2Typical dark site | 1 h 05 min391 subs | 4 h 20 min1,561 subs | 17 h6,243 subs |
| Bortle 3Rural | 1 h 12 min431 subs | 4 h 47 min1,722 subs | 19 h6,887 subs |
| Bortle 4Rural / suburban transition | 1 h 28 min528 subs | 5 h 52 min2,112 subs | 23 h8,447 subs |
| Bortle 5Suburban | 1 h 54 min683 subs | 7 h 35 min2,730 subs | 30 h10,919 subs |
| Bortle 6Bright suburban | 2 h 57 min1,062 subs | 12 h4,247 subs | 47 h16,985 subs |
| Bortle 7Suburban / urban transition | 4 h 57 min1,784 subs | 20 h7,136 subs | 79 h28,544 subs |
| Bortle 8City | 8 h 04 min2,906 subs | 32 h11,623 subs | 130+ h46,490 subs |
| Bortle 9Inner city | 15 h5,298 subs | 59 h21,191 subs | 240+ h84,763 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 5 h 07 min each. The Vespera Pro’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 30WExtends the 11 h battery; 30 W PD per Vaonis.
- 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 frames 1.62° × 1.62° at 1.65″ 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, no EQ mode. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 4 h 47 min1,722 subs | 7 h 35 min2,730 subs | 20 h7,136 subs |
| 20 s | 3 h 54 min702 subs | 6 h 42 min1,206 subs | 19 h3,410 subs |
| 30 s | 3 h 36 min433 subs | 6 h 24 min769 subs | 19 h2,238 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
The square-sensor Vespera with 2 µm pixels. Higher resolution than the II, and correspondingly slower per pixel: expect around double the time for the same per-pixel SNR. Run-out in 2026 and replaced by the Vespera Pro 2.
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.
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? 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 3: 5 h 01 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro 2: 11 h 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