How long to image the Sagittarius Star Cloud with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 20 min (118 subs of 10 s) for a solid image of the Sagittarius Star Cloud. A quick look takes 5 min; a showpiece 1 h 18 min. Under a Bortle 3 rural sky the solid figure drops to 10 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 only just fits, at 93% of the short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 2 min14 subs | 9 min56 subs | 37 min224 subs |
| Bortle 2Typical dark site | 2 min15 subs | 10 min58 subs | 39 min232 subs |
| Bortle 3Rural | 3 min16 subs | 10 min62 subs | 41 min246 subs |
| Bortle 4Rural / suburban transition | 3 min18 subs | 12 min71 subs | 47 min281 subs |
| Bortle 5Suburban | 3 min21 subs | 14 min84 subs | 56 min335 subs |
| Bortle 6Bright suburban | 5 min30 subs | 20 min118 subs | 1 h 18 min470 subs |
| Bortle 7Suburban / urban transition | 8 min46 subs | 30 min182 subs | 2 h 01 min726 subs |
| Bortle 8City | 12 min71 subs | 47 min281 subs | 3 h 07 min1,123 subs |
| Bortle 9Inner city | 21 min124 subs | 1 h 22 min493 subs | 5 h 28 min1,971 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 25 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 Sagittarius Star Cloud is 90′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it only just fits, at 93% of the short side. Centre it carefully: there is no room to crop back afterwards.
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 | 10 min62 subs | 14 min84 subs | 30 min182 subs |
| 20 s | 10 min30 subs | 13 min39 subs | 29 min88 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 29 min58 subs |
About the Sagittarius Star Cloud
A window through the dust into the inner Milky Way, densely packed with stars. Short stacks are enough; it is stars, not nebulosity.
M24, IC 4715 · Star cloud in Sagittarius · magnitude 4.6 · 90′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Star clouds are dense fields of ordinary stars rather than nebulosity. Short subs, no filter, and a modest total keep the field from saturating while still showing the depth of the Milky Way.
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 Sagittarius Star Cloud from a Vespera Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Sagittarius Star Cloud with the ZWO Seestar S50: 9 min from Bortle 6
- Sagittarius Star Cloud with the ZWO Seestar S50 Pro: 10 min from Bortle 6
- Sagittarius Star Cloud with the ZWO Seestar S30: 9 min from Bortle 6
- Sagittarius Star Cloud with the ZWO Seestar S30 Pro: 10 min from Bortle 6
- Sagittarius Star Cloud with the DwarfLab DWARF 3: 13 min from Bortle 6
- Sagittarius Star Cloud with the DwarfLab DWARF mini: 9 min from Bortle 6
- Sagittarius Star Cloud with the DwarfLab Draco: 15 min from Bortle 6
- Sagittarius Star Cloud with the DwarfLab DWARF II: 29 min from Bortle 6
- Sagittarius Star Cloud with the Vaonis Vespera II: 9 min from Bortle 6
- Sagittarius Star Cloud with the Vaonis Vespera 3: 8 min from Bortle 6
- Sagittarius Star Cloud with the Vaonis Vespera Pro 2: 19 min from Bortle 6
- Sagittarius Star Cloud with the Unistellar eQuinox 2: 8 min from Bortle 6
- Sagittarius Star Cloud with the Unistellar Odyssey: 34 min from Bortle 6
- Sagittarius Star Cloud with the Celestron Origin: 5 min from Bortle 6
- Sagittarius Star Cloud with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Sagittarius Star Cloud · All targets for the Vespera Pro