How long to image the M68 with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 1 h 11 min (424 subs of 10 s) for a solid image of the M68. A quick look takes 18 min; a showpiece 4 h 42 min. Under a Bortle 3 rural sky the solid figure drops to 33 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 | 7 min45 subs | 30 min178 subs | 1 h 58 min709 subs |
| Bortle 2Typical dark site | 8 min47 subs | 31 min185 subs | 2 h 03 min740 subs |
| Bortle 3Rural | 8 min50 subs | 33 min200 subs | 2 h 13 min797 subs |
| Bortle 4Rural / suburban transition | 10 min59 subs | 39 min234 subs | 2 h 36 min935 subs |
| Bortle 5Suburban | 12 min73 subs | 48 min289 subs | 3 h 12 min1,155 subs |
| Bortle 6Bright suburban | 18 min106 subs | 1 h 11 min424 subs | 4 h 42 min1,693 subs |
| Bortle 7Suburban / urban transition | 28 min170 subs | 1 h 53 min680 subs | 7 h 33 min2,720 subs |
| Bortle 8City | 45 min270 subs | 3 h1,079 subs | 12 h4,313 subs |
| Bortle 9Inner city | 1 h 20 min482 subs | 5 h 21 min1,928 subs | 21 h7,711 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 32 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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Everything that fits the Vespera Pro →
How it frames
The M68 is 11′ 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 | 33 min200 subs | 48 min289 subs | 1 h 53 min680 subs |
| 20 s | 28 min86 subs | 43 min131 subs | 1 h 49 min326 subs |
| 30 s | 27 min54 subs | 42 min84 subs | 1 h 47 min215 subs |
About the M68
A loose globular in Hydra, low from the UK but easy from lower latitudes.
NGC 4590 · Globular cluster in Hydra · magnitude 7.8 · 11′ · best in Mar, Apr, May. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
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 M68 from a Vespera Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M68 with the ZWO Seestar S50: 32 min from Bortle 6
- M68 with the ZWO Seestar S50 Pro: 35 min from Bortle 6
- M68 with the ZWO Seestar S30: 33 min from Bortle 6
- M68 with the ZWO Seestar S30 Pro: 37 min from Bortle 6
- M68 with the DwarfLab DWARF 3: 46 min from Bortle 6
- M68 with the DwarfLab DWARF mini: 32 min from Bortle 6
- M68 with the DwarfLab Draco: 26 min from Bortle 6
- M68 with the DwarfLab DWARF II: 1 h 47 min from Bortle 6
- M68 with the Vaonis Vespera II: 32 min from Bortle 6
- M68 with the Vaonis Vespera 3: 30 min from Bortle 6
- M68 with the Vaonis Vespera Pro 2: 1 h 07 min from Bortle 6
- M68 with the Unistellar eQuinox 2: 28 min from Bortle 6
- M68 with the Unistellar Odyssey: 2 h 08 min from Bortle 6
- M68 with the Celestron Origin: 8 min from Bortle 6
- M68 with the Celestron Origin Mark II: 12 min from Bortle 6
All telescopes for the M68 · All targets for the Vespera Pro