How long to image the Turtle Nebula with the DwarfLab DWARF mini
From a Bortle 6 suburban sky, the DwarfLab DWARF mini needs about 10 min (41 subs of 15 s with the built-in dual-band filter) for a solid image of the Turtle Nebula. A quick look takes 3 min; a showpiece 41 min. Under a Bortle 3 rural sky the solid figure drops to 8 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is small in the frame, about 5 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 3 min10 subs | 8 min34 subs | 33 min133 subs |
| Bortle 2Typical dark site | 3 min10 subs | 8 min34 subs | 33 min134 subs |
| Bortle 3Rural | 3 min10 subs | 8 min34 subs | 34 min136 subs |
| Bortle 4Rural / suburban transition | 3 min10 subs | 9 min35 subs | 35 min140 subs |
| Bortle 5Suburban | 3 min10 subs | 9 min37 subs | 37 min147 subs |
| Bortle 6Bright suburban | 3 min11 subs | 10 min41 subs | 41 min164 subs |
| Bortle 7Suburban / urban transition | 3 min13 subs | 12 min49 subs | 49 min196 subs |
| Bortle 8City | 4 min16 subs | 15 min62 subs | 1 h 01 min246 subs |
| Bortle 9Inner city | 5 min22 subs | 22 min88 subs | 1 h 28 min352 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 13 min of run time. The DWARF mini’s battery (rated about 3 h 30 min) 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 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.
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Everything that fits the DWARF mini →
How it frames
The Turtle Nebula is 0.3′ across. The DWARF mini frames 2.13° × 1.20° at 3.99″ per pixel, so it is small in the frame, about 5 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.
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 | 8 min34 subs | 9 min37 subs | 12 min49 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 15 min30 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 30 min30 subs |
| 90 s | 45 min30 subs | 45 min30 subs | 45 min30 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 8 min30 subs | 9 min36 subs | 19 min76 subs |
| dual-band | 8 min34 subs | 9 min37 subs | 12 min49 subs |
About the Turtle Nebula
A tiny, very bright planetary in Hercules. A blue-green star-like blob in a smart scope, but an easy catch.
NGC 6210 · Planetary nebula in Hercules · magnitude 9.0 · 0.3′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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 Turtle Nebula from a DWARF mini? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Turtle Nebula with the ZWO Seestar S50: 10 min from Bortle 6
- Turtle Nebula with the ZWO Seestar S50 Pro: 11 min from Bortle 6
- Turtle Nebula with the ZWO Seestar S30: 11 min from Bortle 6
- Turtle Nebula with the ZWO Seestar S30 Pro: 12 min from Bortle 6
- Turtle Nebula with the DwarfLab DWARF 3: 14 min from Bortle 6
- Turtle Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Turtle Nebula with the DwarfLab DWARF II: 40 min from Bortle 6
- Turtle Nebula with the Vaonis Vespera II: 12 min from Bortle 6
- Turtle Nebula with the Vaonis Vespera Pro: 27 min from Bortle 6
- Turtle Nebula with the Vaonis Vespera 3: 12 min from Bortle 6
- Turtle Nebula with the Vaonis Vespera Pro 2: 26 min from Bortle 6
- Turtle Nebula with the Unistellar eQuinox 2: 10 min from Bortle 6
- Turtle Nebula with the Unistellar Odyssey: 46 min from Bortle 6
- Turtle Nebula with the Celestron Origin: 5 min from Bortle 6
- Turtle Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Turtle Nebula · All targets for the DWARF mini