How long to image the M74 with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 5 h 30 min (1,983 subs of 10 s) for a solid image of the M74. A quick look takes 1 h 23 min; a showpiece 22 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 01 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 12% 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 | 25 min152 subs | 1 h 41 min605 subs | 6 h 43 min2,417 subs |
| Bortle 2Typical dark site | 27 min162 subs | 1 h 48 min647 subs | 7 h 11 min2,586 subs |
| Bortle 3Rural | 30 min182 subs | 2 h 01 min727 subs | 8 h 04 min2,906 subs |
| Bortle 4Rural / suburban transition | 38 min231 subs | 2 h 33 min921 subs | 10 h3,683 subs |
| Bortle 5Suburban | 51 min308 subs | 3 h 25 min1,229 subs | 14 h4,913 subs |
| Bortle 6Bright suburban | 1 h 23 min496 subs | 5 h 30 min1,983 subs | 22 h7,931 subs |
| Bortle 7Suburban / urban transition | 2 h 23 min856 subs | 9 h 30 min3,421 subs | 38 h13,683 subs |
| Bortle 8City | 3 h 56 min1,414 subs | 16 h5,654 subs | 63 h22,613 subs |
| Bortle 9Inner city | 7 h 14 min2,604 subs | 29 h10,415 subs | 120+ h41,658 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 7 h 10 min of run time. That is more than one night: over 2 nights, about 3 h 35 min each. The Vespera II’s battery is rated at about 4 h, which is cutting it fine; take a 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 M74 is 10′ × 9.5′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 12% 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 | 2 h 01 min727 subs | 3 h 25 min1,229 subs | 9 h 30 min3,421 subs |
| 20 s | 1 h 41 min305 subs | 3 h 05 min556 subs | 9 h 11 min1,652 subs |
| 30 s | 1 h 35 min190 subs | 2 h 59 min358 subs | 9 h 04 min1,088 subs |
About the M74
A perfect face-on spiral with very low surface brightness, hence the nickname. One of the hardest Messier objects for small scopes.
NGC 628, Phantom Galaxy · Galaxy in Pisces · magnitude 9.4 · 10′ × 9.5′ · best in Sep, Oct, Nov. 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 M74 from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M74 with the ZWO Seestar S50: 5 h 30 min from Bortle 6
- M74 with the ZWO Seestar S50 Pro: 6 h 02 min from Bortle 6
- M74 with the ZWO Seestar S30: 5 h 48 min from Bortle 6
- M74 with the ZWO Seestar S30 Pro: 6 h 23 min from Bortle 6
- M74 with the DwarfLab DWARF 3: 7 h 59 min from Bortle 6
- M74 with the DwarfLab DWARF mini: 5 h 29 min from Bortle 6
- M74 with the DwarfLab Draco: 4 h 31 min from Bortle 6
- M74 with the DwarfLab DWARF II: 19 h from Bortle 6
- M74 with the Vaonis Vespera Pro: 12 h from Bortle 6
- M74 with the Vaonis Vespera 3: 5 h 16 min from Bortle 6
- M74 with the Vaonis Vespera Pro 2: 12 h from Bortle 6
- M74 with the Unistellar eQuinox 2: 5 h 03 min from Bortle 6
- M74 with the Unistellar Odyssey: 23 h from Bortle 6
- M74 with the Celestron Origin: 1 h 27 min from Bortle 6
- M74 with the Celestron Origin Mark II: 1 h 59 min from Bortle 6