How long to image the M84 with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 2 h 49 min (1,015 subs of 10 s) for a solid image of the M84. A quick look takes 42 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 16 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 | 17 min101 subs | 1 h 07 min402 subs | 4 h 27 min1,605 subs |
| Bortle 2Typical dark site | 17 min105 subs | 1 h 10 min420 subs | 4 h 40 min1,680 subs |
| Bortle 3Rural | 19 min114 subs | 1 h 16 min456 subs | 5 h 04 min1,823 subs |
| Bortle 4Rural / suburban transition | 23 min136 subs | 1 h 30 min542 subs | 6 h 01 min2,168 subs |
| Bortle 5Suburban | 28 min170 subs | 1 h 53 min679 subs | 7 h 32 min2,715 subs |
| Bortle 6Bright suburban | 42 min254 subs | 2 h 49 min1,015 subs | 11 h4,057 subs |
| Bortle 7Suburban / urban transition | 1 h 09 min414 subs | 4 h 36 min1,654 subs | 18 h6,615 subs |
| Bortle 8City | 1 h 50 min662 subs | 7 h 21 min2,647 subs | 29 h10,586 subs |
| Bortle 9Inner city | 3 h 18 min1,191 subs | 13 h4,764 subs | 53 h19,054 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 40 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.
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How it frames
The M84 is 6.5′ × 5.6′ 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 16 min456 subs | 1 h 53 min679 subs | 4 h 36 min1,654 subs |
| 20 s | 1 h 05 min195 subs | 1 h 42 min306 subs | 4 h 24 min793 subs |
| 30 s | 1 h 01 min122 subs | 1 h 38 min197 subs | 4 h 21 min522 subs |
About the M84
A lenticular galaxy at the start of Markarian's Chain. The chain is a great wide-field mosaic project.
NGC 4374 · Galaxy in Virgo · magnitude 9.1 · 6.5′ × 5.6′ · 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 M84 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
- M84 with the ZWO Seestar S50: 1 h 19 min from Bortle 6
- M84 with the ZWO Seestar S50 Pro: 1 h 27 min from Bortle 6
- M84 with the ZWO Seestar S30: 1 h 23 min from Bortle 6
- M84 with the ZWO Seestar S30 Pro: 1 h 32 min from Bortle 6
- M84 with the DwarfLab DWARF 3: 1 h 56 min from Bortle 6
- M84 with the DwarfLab DWARF mini: 1 h 19 min from Bortle 6
- M84 with the DwarfLab Draco: 1 h 05 min from Bortle 6
- M84 with the DwarfLab DWARF II: 4 h 29 min from Bortle 6
- M84 with the Vaonis Vespera II: 1 h 19 min from Bortle 6
- M84 with the Vaonis Vespera Pro: 2 h 57 min from Bortle 6
- M84 with the Vaonis Vespera 3: 1 h 16 min from Bortle 6
- M84 with the Unistellar eQuinox 2: 1 h 11 min from Bortle 6
- M84 with the Unistellar Odyssey: 5 h 25 min from Bortle 6
- M84 with the Celestron Origin: 21 min from Bortle 6
- M84 with the Celestron Origin Mark II: 29 min from Bortle 6
All telescopes for the M84 · All targets for the Vespera Pro 2