How long to image the Pleiades with the DwarfLab DWARF mini
From a Bortle 6 suburban sky, the DwarfLab DWARF mini needs about 2 h 41 min (645 subs of 15 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 1.5× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 12 min50 subs | 50 min199 subs | 3 h 19 min795 subs |
| Bortle 2Typical dark site | 13 min54 subs | 53 min213 subs | 3 h 32 min849 subs |
| Bortle 3Rural | 15 min60 subs | 1 h239 subs | 3 h 58 min953 subs |
| Bortle 4Rural / suburban transition | 19 min76 subs | 1 h 15 min301 subs | 5 h 01 min1,204 subs |
| Bortle 5Suburban | 25 min101 subs | 1 h 40 min401 subs | 6 h 40 min1,602 subs |
| Bortle 6Bright suburban | 40 min162 subs | 2 h 41 min645 subs | 11 h2,577 subs |
| Bortle 7Suburban / urban transition | 1 h 09 min278 subs | 4 h 37 min1,110 subs | 18 h4,437 subs |
| Bortle 8City | 1 h 54 min458 subs | 7 h 38 min1,831 subs | 31 h7,324 subs |
| Bortle 9Inner city | 3 h 31 min843 subs | 14 h3,371 subs | 56 h13,481 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 29 min of run time. The DWARF mini’s battery is rated at about 3 h 30 min, less near freezing, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a November night.)
- USB-C PD power bank 10000mAh 20W7,000 mAh inside, about four hours; a PD bank extends the night.
- 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 DWARF mini →
How it frames
The Pleiades is 110′ across. The DWARF mini frames 2.13° × 1.20° at 3.99″ per pixel, so it is 1.5× 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
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 15 s | 1 h239 subs | 1 h 40 min401 subs | 4 h 37 min1,110 subs |
| 30 s | 50 min101 subs | 1 h 31 min182 subs | 4 h 28 min537 subs |
| 60 s | 46 min46 subs | 1 h 26 min87 subs | 4 h 24 min264 subs |
| 90 s | 45 min30 subs | 1 h 25 min57 subs | 4 h 22 min175 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 DwarfLab DWARF mini
DwarfLab’s answer to the Seestar S30: same sensor and focal length, big pixels, dual-band filter built in, and 90 s subs in EQ mode. Sensitivity over megapixels.
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 90 s is the ceiling. Built-in Astro (430 to 690 nm), dark-frame and dual-band Hα / OIII filters; no plain VIS filter on the tele camera.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 15 s and 90 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 DWARF mini? 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: 2 h 42 min from Bortle 6
- 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 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 DWARF mini