How long to image the M66 with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 41 min (246 subs of 10 s) for a solid image of the M66. A quick look takes 10 min; a showpiece 2 h 44 min. Under a Bortle 3 rural sky the solid figure drops to 18 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 | 4 min24 subs | 16 min94 subs | 1 h 02 min375 subs |
| Bortle 2Typical dark site | 4 min25 subs | 16 min99 subs | 1 h 06 min394 subs |
| Bortle 3Rural | 4 min27 subs | 18 min108 subs | 1 h 11 min429 subs |
| Bortle 4Rural / suburban transition | 5 min33 subs | 21 min129 subs | 1 h 26 min515 subs |
| Bortle 5Suburban | 7 min41 subs | 27 min163 subs | 1 h 48 min651 subs |
| Bortle 6Bright suburban | 10 min62 subs | 41 min246 subs | 2 h 44 min984 subs |
| Bortle 7Suburban / urban transition | 17 min102 subs | 1 h 07 min405 subs | 4 h 30 min1,619 subs |
| Bortle 8City | 27 min163 subs | 1 h 49 min652 subs | 7 h 14 min2,605 subs |
| Bortle 9Inner city | 49 min295 subs | 3 h 16 min1,177 subs | 13 h4,707 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 53 min of run time. The Vespera II’s battery (rated about 4 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 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 M66 is 9′ × 4′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ 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, no EQ mode. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 18 min108 subs | 27 min163 subs | 1 h 07 min405 subs |
| 20 s | 16 min48 subs | 25 min75 subs | 1 h 05 min196 subs |
| 30 s | 15 min30 subs | 24 min49 subs | 1 h 05 min130 subs |
About the M66
The brightest of the Leo Triplet, with asymmetric arms from a past encounter.
NGC 3627 · Galaxy in Leo · magnitude 8.9 · 9′ × 4′ · best in Feb, Mar, Apr. 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 M66 from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M66 with the ZWO Seestar S50: 41 min from Bortle 6
- M66 with the ZWO Seestar S50 Pro: 45 min from Bortle 6
- M66 with the ZWO Seestar S30: 43 min from Bortle 6
- M66 with the ZWO Seestar S30 Pro: 47 min from Bortle 6
- M66 with the DwarfLab DWARF 3: 1 h from Bortle 6
- M66 with the DwarfLab DWARF mini: 41 min from Bortle 6
- M66 with the DwarfLab Draco: 34 min from Bortle 6
- M66 with the DwarfLab DWARF II: 2 h 18 min from Bortle 6
- M66 with the Vaonis Vespera Pro: 1 h 31 min from Bortle 6
- M66 with the Vaonis Vespera 3: 39 min from Bortle 6
- M66 with the Vaonis Vespera Pro 2: 1 h 27 min from Bortle 6
- M66 with the Unistellar eQuinox 2: 36 min from Bortle 6
- M66 with the Unistellar Odyssey: 2 h 46 min from Bortle 6
- M66 with the Celestron Origin: 11 min from Bortle 6
- M66 with the Celestron Origin Mark II: 15 min from Bortle 6