How long to image the M88 with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 3 h 54 min (1,403 subs of 10 s) for a solid image of the M88. A quick look takes 58 min; a showpiece 16 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 42 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 7% 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 | 22 min134 subs | 1 h 29 min535 subs | 5 h 56 min2,138 subs |
| Bortle 2Typical dark site | 23 min141 subs | 1 h 34 min562 subs | 6 h 14 min2,245 subs |
| Bortle 3Rural | 25 min153 subs | 1 h 42 min612 subs | 6 h 48 min2,447 subs |
| Bortle 4Rural / suburban transition | 31 min184 subs | 2 h 02 min734 subs | 8 h 09 min2,935 subs |
| Bortle 5Suburban | 39 min232 subs | 2 h 35 min928 subs | 10 h3,710 subs |
| Bortle 6Bright suburban | 58 min351 subs | 3 h 54 min1,403 subs | 16 h5,610 subs |
| Bortle 7Suburban / urban transition | 1 h 36 min577 subs | 6 h 25 min2,308 subs | 26 h9,230 subs |
| Bortle 8City | 2 h 35 min929 subs | 10 h3,713 subs | 41 h14,851 subs |
| Bortle 9Inner city | 4 h 40 min1,678 subs | 19 h6,710 subs | 75 h26,839 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 5 h 04 min of run time. The Vespera Pro 2’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 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.
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 Pro 2 →
How it frames
The M88 is 7′ × 4′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 7% 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 | 1 h 42 min612 subs | 2 h 35 min928 subs | 6 h 25 min2,308 subs |
| 20 s | 1 h 26 min258 subs | 2 h 19 min416 subs | 6 h 09 min1,106 subs |
| 30 s | 1 h 21 min162 subs | 2 h 13 min267 subs | 6 h 03 min727 subs |
About the M88
A tilted spiral in the Virgo cluster with tightly wound arms.
NGC 4501 · Galaxy in Coma Berenices · magnitude 9.6 · 7′ × 4′ · 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 M88 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
- M88 with the ZWO Seestar S50: 1 h 50 min from Bortle 6
- M88 with the ZWO Seestar S50 Pro: 2 h from Bortle 6
- M88 with the ZWO Seestar S30: 1 h 55 min from Bortle 6
- M88 with the ZWO Seestar S30 Pro: 2 h 07 min from Bortle 6
- M88 with the DwarfLab DWARF 3: 2 h 40 min from Bortle 6
- M88 with the DwarfLab DWARF mini: 1 h 49 min from Bortle 6
- M88 with the DwarfLab Draco: 1 h 30 min from Bortle 6
- M88 with the DwarfLab DWARF II: 6 h 13 min from Bortle 6
- M88 with the Vaonis Vespera II: 1 h 50 min from Bortle 6
- M88 with the Vaonis Vespera Pro: 4 h 05 min from Bortle 6
- M88 with the Vaonis Vespera 3: 1 h 45 min from Bortle 6
- M88 with the Unistellar eQuinox 2: 1 h 39 min from Bortle 6
- M88 with the Unistellar Odyssey: 7 h 34 min from Bortle 6
- M88 with the Celestron Origin: 29 min from Bortle 6
- M88 with the Celestron Origin Mark II: 40 min from Bortle 6
All telescopes for the M88 · All targets for the Vespera Pro 2