How long to image the Pleiades with the ZWO Seestar S50
From a Bortle 6 suburban sky, the ZWO Seestar S50 needs about 2 h 42 min (971 subs of 10 s) for a solid image of the Pleiades. A quick look takes 40 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h. 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 is 2.6× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 13 min76 subs | 50 min303 subs | 3 h 22 min1,210 subs |
| Bortle 2Typical dark site | 13 min81 subs | 54 min323 subs | 3 h 35 min1,292 subs |
| Bortle 3Rural | 15 min91 subs | 1 h362 subs | 4 h 01 min1,447 subs |
| Bortle 4Rural / suburban transition | 19 min114 subs | 1 h 16 min456 subs | 5 h 04 min1,824 subs |
| Bortle 5Suburban | 25 min152 subs | 1 h 41 min605 subs | 6 h 43 min2,420 subs |
| Bortle 6Bright suburban | 40 min243 subs | 2 h 42 min971 subs | 11 h3,884 subs |
| Bortle 7Suburban / urban transition | 1 h 10 min418 subs | 4 h 38 min1,669 subs | 19 h6,673 subs |
| Bortle 8City | 1 h 55 min688 subs | 7 h 38 min2,751 subs | 31 h11,004 subs |
| Bortle 9Inner city | 3 h 31 min1,265 subs | 14 h5,060 subs | 56 h20,239 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 30 min of run time. The Seestar S50’s battery (rated about 6 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, and 30% off the battery for a November night.)
- USB-C power bank 20000mAh 5V 3AThe S50 draws 5 V 3 A over USB-C and runs while charging; no PD needed.
- Seestar S50 dew shieldThe built-in heater copes with most nights; a shield helps in heavy dew and blocks stray light.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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Everything that fits the Seestar S50 →
How it frames
The Pleiades is 110′ across. The Seestar S50 frames 1.28° × 0.72° at 2.39″ per pixel, so it is 2.6× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.
Longer subs
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode (app 2.5 and later). Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 1 h362 subs | 1 h 41 min605 subs | 4 h 38 min1,669 subs |
| 20 s | 51 min153 subs | 1 h 31 min274 subs | 4 h 29 min806 subs |
| 30 s | 48 min96 subs | 1 h 28 min177 subs | 4 h 25 min531 subs |
| 60 s | 44 min45 subs | 1 h 25 min85 subs | 4 h 22 min263 subs |
Leave the dual-band filter out for the Pleiades. It is a reflection nebula, and it shines right across the spectrum. A dual-band filter keeps two emission lines and throws the rest away, so most of the light you came for is being stopped along with the sky. From a Bortle 6 sky it would be roughly 12 times slower.
About the Pleiades
The stars take seconds. The blue reflection nebulosity around them is faint and needs hours from any sky, and no filter helps because it is starlight, not emission.
M45, Seven Sisters · Reflection nebula in Taurus · magnitude 1.6 · 110′ · best in Oct, Nov, Dec. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Reflection nebulae are starlight scattered by dust, so they are broadband and blue. A dual-band filter removes almost all of it; do not use one. These are among the faintest structures a smart scope can attempt and the figures run long. A dark sky matters more here than for any other type, and the Moon must be down.
About the ZWO Seestar S50
The scope that made smart astrophotography mainstream. 50 mm triplet, 2 MP sensor, dual-band filter on a wheel. Alt-Az stacking at 10 s, EQ mode unlocks 60 s. Out of production since 2026 and replaced by the S50 Pro, but there are a great many in use.
10, 20 and 30 s in Alt-Az; 60 s only in EQ mode (app 2.5 and later). Built-in dual-band light-pollution filter, switchable in the app.
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 60 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 Pleiades from a Seestar S50? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Pleiades with the ZWO Seestar S50 Pro: 2 h 57 min from Bortle 6
- Pleiades with the ZWO Seestar S30: 2 h 50 min from Bortle 6
- Pleiades with the ZWO Seestar S30 Pro: 3 h 08 min from Bortle 6
- Pleiades with the DwarfLab DWARF 3: 3 h 55 min from Bortle 6
- Pleiades with the DwarfLab DWARF mini: 2 h 41 min from Bortle 6
- Pleiades with the DwarfLab Draco: 2 h 13 min from Bortle 6
- Pleiades with the DwarfLab DWARF II: 9 h 16 min from Bortle 6
- Pleiades with the Vaonis Vespera II: 2 h 42 min from Bortle 6
- Pleiades with the Vaonis Vespera Pro: 6 h 03 min from Bortle 6
- Pleiades with the Vaonis Vespera 3: 2 h 35 min from Bortle 6
- Pleiades with the Vaonis Vespera Pro 2: 5 h 46 min from Bortle 6
- Pleiades with the Unistellar eQuinox 2: 2 h 28 min from Bortle 6
- Pleiades with the Unistellar Odyssey: 11 h from Bortle 6
- Pleiades with the Celestron Origin: 43 min from Bortle 6
- Pleiades with the Celestron Origin Mark II: 59 min from Bortle 6
All telescopes for the Pleiades · All targets for the Seestar S50