How long to image the Owl Nebula with the DwarfLab DWARF 3
From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 49 min (198 subs of 15 s with the built-in dual-band filter) for a solid image of the Owl Nebula. A quick look takes 12 min; a showpiece 3 h 17 min. Under a Bortle 3 rural sky the solid figure drops to 35 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 3% 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 | 8 min34 subs | 34 min135 subs | 2 h 15 min540 subs |
| Bortle 2Typical dark site | 9 min35 subs | 34 min137 subs | 2 h 17 min547 subs |
| Bortle 3Rural | 9 min36 subs | 35 min141 subs | 2 h 20 min562 subs |
| Bortle 4Rural / suburban transition | 9 min38 subs | 37 min150 subs | 2 h 29 min597 subs |
| Bortle 5Suburban | 10 min41 subs | 41 min164 subs | 2 h 43 min653 subs |
| Bortle 6Bright suburban | 12 min50 subs | 49 min198 subs | 3 h 17 min790 subs |
| Bortle 7Suburban / urban transition | 16 min66 subs | 1 h 06 min263 subs | 4 h 22 min1,050 subs |
| Bortle 8City | 23 min91 subs | 1 h 31 min364 subs | 6 h 04 min1,455 subs |
| Bortle 9Inner city | 36 min145 subs | 2 h 25 min580 subs | 9 h 40 min2,319 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 04 min of run time. The DWARF 3’s battery (rated about 5 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 20000mAh 18W18 W PD input and it runs while charging; needs a C-to-C cable for PD.
- 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 3 →
How it frames
The Owl Nebula is 3.4′ × 3.3′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it fills 3% of the frame’s short side.
Longer subs
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 15 s | 35 min141 subs | 41 min164 subs | 1 h 06 min263 subs |
| 30 s | 32 min64 subs | 37 min75 subs | 1 h 02 min125 subs |
| 60 s | 30 min31 subs | 36 min36 subs | 1 h 01 min61 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 32 min127 subs | 50 min201 subs | 2 h 11 min526 subs |
| dual-band | 35 min141 subs | 41 min164 subs | 1 h 06 min263 subs |
About the Owl Nebula
A round planetary with two dark eyes. Large for its class and low in surface brightness; dual-band helps a lot.
M97, NGC 3587 · Planetary nebula in Ursa Major · magnitude 9.9 · 3.4′ × 3.3′ · best in Feb, Mar, Apr. 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 3
Small pixels on a 35 mm f/4.3 lens give a sharper image than its aperture suggests, and EQ mode with 60 s subs makes it the read-noise winner in dark skies.
Auto mode caps subs at 15 s; 30 s and longer need EQ mode, and 60 s is the ceiling on the tele camera. Three built-in filters: VIS, Astro (430 to 690 nm) and dual-band Hα 656 nm / OIII 501 nm.
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 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 Owl Nebula from a DWARF 3? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Owl Nebula with the ZWO Seestar S50: 38 min from Bortle 6
- Owl Nebula with the ZWO Seestar S50 Pro: 42 min from Bortle 6
- Owl Nebula with the ZWO Seestar S30: 43 min from Bortle 6
- Owl Nebula with the ZWO Seestar S30 Pro: 45 min from Bortle 6
- Owl Nebula with the DwarfLab DWARF mini: 37 min from Bortle 6
- Owl Nebula with the DwarfLab Draco: 30 min from Bortle 6
- Owl Nebula with the DwarfLab DWARF II: 3 h from Bortle 6
- Owl Nebula with the Vaonis Vespera II: 54 min from Bortle 6
- Owl Nebula with the Vaonis Vespera Pro: 1 h 59 min from Bortle 6
- Owl Nebula with the Vaonis Vespera 3: 51 min from Bortle 6
- Owl Nebula with the Vaonis Vespera Pro 2: 1 h 54 min from Bortle 6
- Owl Nebula with the Unistellar eQuinox 2: 47 min from Bortle 6
- Owl Nebula with the Unistellar Odyssey: 3 h 36 min from Bortle 6
- Owl Nebula with the Celestron Origin: 14 min from Bortle 6
- Owl Nebula with the Celestron Origin Mark II: 20 min from Bortle 6
All telescopes for the Owl Nebula · All targets for the DWARF 3