How long to image the Ghost of Cassiopeia with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 2 h 50 min (1,021 subs of 10 s) for a solid image of the Ghost of Cassiopeia. A quick look takes 43 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 05 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 12% 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 | 14 min82 subs | 55 min328 subs | 3 h 38 min1,309 subs |
| Bortle 2Typical dark site | 15 min88 subs | 58 min349 subs | 3 h 52 min1,394 subs |
| Bortle 3Rural | 16 min98 subs | 1 h 05 min389 subs | 4 h 19 min1,556 subs |
| Bortle 4Rural / suburban transition | 20 min122 subs | 1 h 21 min487 subs | 5 h 24 min1,946 subs |
| Bortle 5Suburban | 27 min161 subs | 1 h 47 min642 subs | 7 h 07 min2,565 subs |
| Bortle 6Bright suburban | 43 min256 subs | 2 h 50 min1,021 subs | 11 h4,084 subs |
| Bortle 7Suburban / urban transition | 1 h 13 min437 subs | 4 h 51 min1,745 subs | 19 h6,979 subs |
| Bortle 8City | 2 h718 subs | 7 h 58 min2,869 subs | 32 h11,473 subs |
| Bortle 9Inner city | 3 h 39 min1,317 subs | 15 h5,265 subs | 58 h21,057 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 41 min of run time. The Vespera II’s battery is rated at about 4 h, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB-C PD power bank 20000mAh 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
- Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the Vespera II →
How it frames
The Ghost of Cassiopeia is 10′ × 3′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 12% 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 | 1 h 05 min389 subs | 1 h 47 min642 subs | 4 h 51 min1,745 subs |
| 20 s | 55 min165 subs | 1 h 37 min292 subs | 4 h 41 min843 subs |
| 30 s | 52 min104 subs | 1 h 34 min188 subs | 4 h 38 min556 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 1 h 05 min389 subs | 1 h 47 min642 subs | 4 h 51 min1,745 subs |
| dual-band (Dual Band filter), clip-on | 1 h 16 min455 subs | 1 h 29 min533 subs | 2 h 25 min870 subs |
The Vespera II has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted. 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 II
A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.
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; the app detects which is fitted.
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 II? 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 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 Vaonis Vespera Pro 2: 6 h 03 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 II