How long to image the Pinwheel Galaxy with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 4 h 37 min (1,661 subs of 10 s) for a solid image of the Pinwheel Galaxy. A quick look takes 1 h 09 min; a showpiece 18 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 40 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 34% 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 | 21 min125 subs | 1 h 23 min499 subs | 5 h 32 min1,995 subs |
| Bortle 2Typical dark site | 22 min134 subs | 1 h 29 min535 subs | 5 h 56 min2,137 subs |
| Bortle 3Rural | 25 min151 subs | 1 h 40 min602 subs | 6 h 41 min2,407 subs |
| Bortle 4Rural / suburban transition | 32 min192 subs | 2 h 08 min766 subs | 8 h 30 min3,061 subs |
| Bortle 5Suburban | 43 min257 subs | 2 h 51 min1,025 subs | 11 h4,098 subs |
| Bortle 6Bright suburban | 1 h 09 min416 subs | 4 h 37 min1,661 subs | 18 h6,642 subs |
| Bortle 7Suburban / urban transition | 2 h719 subs | 7 h 59 min2,873 subs | 32 h11,489 subs |
| Bortle 8City | 3 h 18 min1,189 subs | 13 h4,754 subs | 53 h19,014 subs |
| Bortle 9Inner city | 6 h 05 min2,192 subs | 24 h8,766 subs | 97 h35,064 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 6 h of run time. The Vespera II’s battery is rated at about 4 h, so the session needs an external 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.
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Everything that fits the Vespera II →
How it frames
The Pinwheel Galaxy is 29′ × 27′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 34% 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 40 min602 subs | 2 h 51 min1,025 subs | 7 h 59 min2,873 subs |
| 20 s | 1 h 24 min252 subs | 2 h 34 min463 subs | 7 h 42 min1,387 subs |
| 30 s | 1 h 18 min157 subs | 2 h 29 min298 subs | 7 h 37 min914 subs |
About the Pinwheel Galaxy
Big, face-on and faint. Its total magnitude is flattering; spread over half a degree the arms are dim and demand hours, especially from suburban skies.
M101, NGC 5457 · Galaxy in Ursa Major · magnitude 7.9 · 29′ × 27′ · best in Apr, May, Jun. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
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 Pinwheel Galaxy from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Pinwheel Galaxy with the ZWO Seestar S50: 4 h 37 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S50 Pro: 5 h 03 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S30: 4 h 51 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S30 Pro: 5 h 21 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF 3: 6 h 41 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF mini: 4 h 35 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab Draco: 3 h 47 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF II: 16 h from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera Pro: 10 h from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera 3: 4 h 24 min from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera Pro 2: 9 h 52 min from Bortle 6
- Pinwheel Galaxy with the Unistellar eQuinox 2: 4 h 14 min from Bortle 6
- Pinwheel Galaxy with the Unistellar Odyssey: 20 h from Bortle 6
- Pinwheel Galaxy with the Celestron Origin: 1 h 13 min from Bortle 6
- Pinwheel Galaxy with the Celestron Origin Mark II: 1 h 40 min from Bortle 6
All telescopes for the Pinwheel Galaxy · All targets for the Vespera II