How long to image the Cat's Eye Nebula with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 27 min (164 subs of 10 s) for a solid image of the Cat's Eye Nebula. A quick look takes 7 min; a showpiece 1 h 49 min. Under a Bortle 3 rural sky the solid figure drops to 15 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 15 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 4 min22 subs | 14 min85 subs | 56 min337 subs |
| Bortle 2Typical dark site | 4 min22 subs | 14 min87 subs | 58 min346 subs |
| Bortle 3Rural | 4 min23 subs | 15 min92 subs | 1 h 01 min365 subs |
| Bortle 4Rural / suburban transition | 4 min26 subs | 17 min103 subs | 1 h 08 min409 subs |
| Bortle 5Suburban | 5 min30 subs | 20 min120 subs | 1 h 20 min480 subs |
| Bortle 6Bright suburban | 7 min41 subs | 27 min164 subs | 1 h 49 min654 subs |
| Bortle 7Suburban / urban transition | 10 min62 subs | 41 min247 subs | 2 h 44 min986 subs |
| Bortle 8City | 16 min94 subs | 1 h 02 min375 subs | 4 h 10 min1,500 subs |
| Bortle 9Inner city | 27 min163 subs | 1 h 48 min650 subs | 7 h 13 min2,598 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 35 min of run time. The Vespera Pro’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 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 Cat's Eye Nebula is 0.4′ × 0.3′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it is small in the frame, about 15 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, no EQ mode. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 15 min92 subs | 20 min120 subs | 41 min247 subs |
| 20 s | 14 min41 subs | 18 min56 subs | 40 min119 subs |
| 30 s | 15 min30 subs | 18 min36 subs | 39 min79 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 15 min92 subs | 20 min120 subs | 41 min247 subs |
| dual-band (Dual Band filter), clip-on | 21 min124 subs | 22 min133 subs | 28 min171 subs |
The Vespera Pro 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
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 Cat's Eye Nebula from a Vespera Pro? 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 3: 12 min from Bortle 6
- Cat's Eye Nebula with the Vaonis Vespera Pro 2: 26 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