How long to image the Ghost of Cassiopeia with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 6 h 03 min (2,181 subs of 10 s) for a solid image of the Ghost of Cassiopeia. A quick look takes 1 h 31 min; a showpiece 24 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 31 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 10% 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 | 32 min195 subs | 2 h 10 min780 subs | 8 h 39 min3,117 subs |
| Bortle 2Typical dark site | 34 min206 subs | 2 h 17 min823 subs | 9 h 08 min3,289 subs |
| Bortle 3Rural | 38 min226 subs | 2 h 31 min904 subs | 10 h3,615 subs |
| Bortle 4Rural / suburban transition | 46 min276 subs | 3 h 03 min1,101 subs | 12 h4,404 subs |
| Bortle 5Suburban | 59 min354 subs | 3 h 56 min1,414 subs | 16 h5,654 subs |
| Bortle 6Bright suburban | 1 h 31 min546 subs | 6 h 03 min2,181 subs | 24 h8,721 subs |
| Bortle 7Suburban / urban transition | 2 h 32 min911 subs | 10 h3,642 subs | 40 h14,565 subs |
| Bortle 8City | 4 h 06 min1,478 subs | 16 h5,910 subs | 66 h23,640 subs |
| Bortle 9Inner city | 7 h 28 min2,687 subs | 30 h10,748 subs | 120+ h42,992 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 7 h 52 min of run time. That is more than one night: over 2 nights, about 3 h 56 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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Everything that fits the Vespera Pro 2 →
How it frames
The Ghost of Cassiopeia is 10′ × 3′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 10% 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 31 min904 subs | 3 h 56 min1,414 subs | 10 h3,642 subs |
| 20 s | 2 h 05 min375 subs | 3 h 30 min630 subs | 9 h 41 min1,744 subs |
| 30 s | 1 h 56 min233 subs | 3 h 21 min403 subs | 9 h 33 min1,146 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 2 h 31 min904 subs | 3 h 56 min1,414 subs | 10 h3,642 subs |
| dual-band (Dual Band filter), clip-on | 3 h 13 min1,161 subs | 3 h 39 min1,317 subs | 5 h 33 min1,999 subs |
The Vespera Pro 2 has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. On an emission target like this it is the single biggest upgrade you can make.
About the Ghost of Cassiopeia
A small emission and reflection wisp being eroded by the star Gamma Cassiopeiae. Keep the bright star's glare under control.
IC 63 · Emission nebula in Cassiopeia · magnitude 10.0 · 10′ × 3′ · best in Sep, Oct, Nov. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 Ghost of Cassiopeia 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
- Ghost of Cassiopeia with the ZWO Seestar S50: 1 h 48 min from Bortle 6
- Ghost of Cassiopeia with the ZWO Seestar S50 Pro: 2 h 01 min from Bortle 6
- Ghost of Cassiopeia with the ZWO Seestar S30: 2 h 06 min from Bortle 6
- Ghost of Cassiopeia with the ZWO Seestar S30 Pro: 2 h 11 min from Bortle 6
- Ghost of Cassiopeia with the DwarfLab DWARF 3: 2 h 15 min from Bortle 6
- Ghost of Cassiopeia with the DwarfLab DWARF mini: 1 h 46 min from Bortle 6
- Ghost of Cassiopeia with the DwarfLab Draco: 1 h 26 min from Bortle 6
- Ghost of Cassiopeia with the DwarfLab DWARF II: 9 h 43 min from Bortle 6
- Ghost of Cassiopeia with the Vaonis Vespera II: 2 h 50 min from Bortle 6
- Ghost of Cassiopeia with the Vaonis Vespera Pro: 6 h 21 min from Bortle 6
- Ghost of Cassiopeia with the Vaonis Vespera 3: 2 h 43 min from Bortle 6
- Ghost of Cassiopeia with the Unistellar eQuinox 2: 2 h 35 min from Bortle 6
- Ghost of Cassiopeia with the Unistellar Odyssey: 12 h from Bortle 6
- Ghost of Cassiopeia with the Celestron Origin: 45 min from Bortle 6
- Ghost of Cassiopeia with the Celestron Origin Mark II: 1 h 02 min from Bortle 6
All telescopes for the Ghost of Cassiopeia · All targets for the Vespera Pro 2