How long to image the M90 with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 5 h 24 min (1,943 subs of 10 s) for a solid image of the M90. A quick look takes 1 h 21 min; a showpiece 22 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 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 fills 10% 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 | 29 min176 subs | 1 h 57 min703 subs | 7 h 48 min2,810 subs |
| Bortle 2Typical dark site | 31 min186 subs | 2 h 03 min741 subs | 8 h 14 min2,963 subs |
| Bortle 3Rural | 34 min204 subs | 2 h 15 min813 subs | 9 h 02 min3,251 subs |
| Bortle 4Rural / suburban transition | 41 min247 subs | 2 h 45 min988 subs | 11 h3,949 subs |
| Bortle 5Suburban | 53 min316 subs | 3 h 31 min1,264 subs | 14 h5,055 subs |
| Bortle 6Bright suburban | 1 h 21 min486 subs | 5 h 24 min1,943 subs | 22 h7,770 subs |
| Bortle 7Suburban / urban transition | 2 h 15 min809 subs | 8 h 59 min3,236 subs | 36 h12,942 subs |
| Bortle 8City | 3 h 38 min1,311 subs | 15 h5,243 subs | 58 h20,972 subs |
| Bortle 9Inner city | 6 h 37 min2,382 subs | 26 h9,525 subs | 110+ h38,099 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 7 h 01 min of run time. That is more than one night: over 2 nights, about 3 h 30 min each. The Vespera Pro 2’s battery (rated about 11 h) should cover each night; 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 30WExternal bank extends the 11 h battery.
- 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 2 →
How it frames
The M90 is 9.5′ × 4.5′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 10% 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; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 2 h 15 min813 subs | 3 h 31 min1,264 subs | 8 h 59 min3,236 subs |
| 20 s | 1 h 53 min339 subs | 3 h 08 min564 subs | 8 h 36 min1,550 subs |
| 30 s | 1 h 45 min211 subs | 3 h361 subs | 8 h 29 min1,018 subs |
About the M90
A large spiral whose arms have been stripped by the cluster medium. Smooth and elongated.
NGC 4569 · Galaxy in Virgo · magnitude 9.5 · 9.5′ × 4.5′ · best in Mar, Apr, May. 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 Pro 2
The square-sensor 2026 Vespera with 2 µm pixels. Sharper than the Vespera 3 on small targets and correspondingly slower per pixel; the 12.5 MP square frame suits galaxies and planetaries.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. 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 M90 from a Vespera Pro 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M90 with the ZWO Seestar S50: 2 h 32 min from Bortle 6
- M90 with the ZWO Seestar S50 Pro: 2 h 46 min from Bortle 6
- M90 with the ZWO Seestar S30: 2 h 39 min from Bortle 6
- M90 with the ZWO Seestar S30 Pro: 2 h 56 min from Bortle 6
- M90 with the DwarfLab DWARF 3: 3 h 40 min from Bortle 6
- M90 with the DwarfLab DWARF mini: 2 h 31 min from Bortle 6
- M90 with the DwarfLab Draco: 2 h 04 min from Bortle 6
- M90 with the DwarfLab DWARF II: 8 h 39 min from Bortle 6
- M90 with the Vaonis Vespera II: 2 h 32 min from Bortle 6
- M90 with the Vaonis Vespera Pro: 5 h 40 min from Bortle 6
- M90 with the Vaonis Vespera 3: 2 h 25 min from Bortle 6
- M90 with the Unistellar eQuinox 2: 2 h 18 min from Bortle 6
- M90 with the Unistellar Odyssey: 11 h from Bortle 6
- M90 with the Celestron Origin: 40 min from Bortle 6
- M90 with the Celestron Origin Mark II: 55 min from Bortle 6
All telescopes for the M90 · All targets for the Vespera Pro 2