How long to image the Cat's Eye Nebula with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 26 min (157 subs of 10 s) for a solid image of the Cat's Eye Nebula. A quick look takes 7 min; a showpiece 1 h 44 min. Under a Bortle 3 rural sky the solid figure drops to 14 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 is small in the frame, about 14 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 3 min20 subs | 13 min80 subs | 53 min320 subs |
| Bortle 2Typical dark site | 3 min21 subs | 14 min83 subs | 55 min329 subs |
| Bortle 3Rural | 4 min22 subs | 14 min87 subs | 58 min347 subs |
| Bortle 4Rural / suburban transition | 4 min25 subs | 16 min98 subs | 1 h 05 min390 subs |
| Bortle 5Suburban | 5 min29 subs | 19 min115 subs | 1 h 16 min458 subs |
| Bortle 6Bright suburban | 7 min40 subs | 26 min157 subs | 1 h 44 min625 subs |
| Bortle 7Suburban / urban transition | 10 min59 subs | 39 min236 subs | 2 h 37 min943 subs |
| Bortle 8City | 15 min90 subs | 1 h360 subs | 3 h 59 min1,437 subs |
| Bortle 9Inner city | 26 min156 subs | 1 h 44 min623 subs | 6 h 55 min2,491 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 34 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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Everything that fits the Vespera Pro 2 →
How it frames
The Cat's Eye Nebula is 0.4′ × 0.3′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it is small in the frame, about 14 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.
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 | 14 min87 subs | 19 min115 subs | 39 min236 subs |
| 20 s | 13 min40 subs | 18 min53 subs | 38 min114 subs |
| 30 s | 15 min30 subs | 17 min35 subs | 37 min75 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 14 min87 subs | 19 min115 subs | 39 min236 subs |
| dual-band (Dual Band filter), clip-on | 19 min117 subs | 21 min126 subs | 27 min163 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 Cat's Eye Nebula
A tiny, intensely bright planetary. The core saturates in seconds; the faint outer halo around it is a long dual-band project.
NGC 6543, Caldwell 6 · Planetary nebula in Draco · magnitude 9.0 · 0.4′ × 0.3′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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 Cat's Eye Nebula 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
- Cat's Eye Nebula with the ZWO Seestar S50: 10 min from Bortle 6
- Cat's Eye Nebula with the ZWO Seestar S50 Pro: 11 min from Bortle 6
- Cat's Eye Nebula with the ZWO Seestar S30: 11 min from Bortle 6
- Cat's Eye Nebula with the ZWO Seestar S30 Pro: 12 min from Bortle 6
- Cat's Eye Nebula with the DwarfLab DWARF 3: 14 min from Bortle 6
- Cat's Eye Nebula with the DwarfLab DWARF mini: 10 min from Bortle 6
- Cat's Eye Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Cat's Eye Nebula with the DwarfLab DWARF II: 40 min from Bortle 6
- Cat's Eye Nebula with the Vaonis Vespera II: 12 min from Bortle 6
- Cat's Eye Nebula with the Vaonis Vespera Pro: 27 min from Bortle 6
- Cat's Eye Nebula with the Vaonis Vespera 3: 12 min from Bortle 6
- Cat's Eye Nebula with the Unistellar eQuinox 2: 10 min from Bortle 6
- Cat's Eye Nebula with the Unistellar Odyssey: 46 min from Bortle 6
- Cat's Eye Nebula with the Celestron Origin: 5 min from Bortle 6
- Cat's Eye Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Cat's Eye Nebula · All targets for the Vespera Pro 2