How long to image the Cocoon Nebula with the DwarfLab DWARF mini
From a Bortle 6 suburban sky, the DwarfLab DWARF mini needs about 2 h 55 min (701 subs of 15 s with the built-in dual-band filter) for a solid image of the Cocoon Nebula. A quick look takes 44 min; a showpiece 12 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 59 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 17% 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 | 28 min114 subs | 1 h 54 min455 subs | 7 h 34 min1,817 subs |
| Bortle 2Typical dark site | 29 min116 subs | 1 h 55 min462 subs | 7 h 42 min1,847 subs |
| Bortle 3Rural | 30 min119 subs | 1 h 59 min476 subs | 7 h 56 min1,904 subs |
| Bortle 4Rural / suburban transition | 32 min128 subs | 2 h 08 min511 subs | 8 h 31 min2,043 subs |
| Bortle 5Suburban | 35 min142 subs | 2 h 21 min566 subs | 9 h 26 min2,263 subs |
| Bortle 6Bright suburban | 44 min176 subs | 2 h 55 min701 subs | 12 h2,803 subs |
| Bortle 7Suburban / urban transition | 1 h240 subs | 3 h 59 min958 subs | 16 h3,831 subs |
| Bortle 8City | 1 h 25 min340 subs | 5 h 39 min1,357 subs | 23 h5,428 subs |
| Bortle 9Inner city | 2 h 18 min553 subs | 9 h 12 min2,209 subs | 37 h8,834 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 48 min of run time. The DWARF mini’s battery is rated at about 3 h 30 min, so the session needs an external power bank. (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 Cocoon Nebula is 12′ across. The DWARF mini frames 2.13° × 1.20° at 3.99″ per pixel, so it fills 17% of the frame’s short side.
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 h 59 min476 subs | 2 h 21 min566 subs | 3 h 59 min958 subs |
| 30 s | 1 h 25 min171 subs | 1 h 48 min216 subs | 3 h 26 min412 subs |
| 60 s | 1 h 09 min69 subs | 1 h 31 min91 subs | 3 h 09 min190 subs |
| 90 s | 1 h 03 min42 subs | 1 h 25 min57 subs | 3 h 03 min123 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 1 h 44 min418 subs | 2 h 58 min711 subs | 8 h 18 min1,991 subs |
| dual-band | 1 h 59 min476 subs | 2 h 21 min566 subs | 3 h 59 min958 subs |
About the Cocoon Nebula
A round emission and reflection nebula at the end of a long dark lane. Mixed light, so a broadband stack keeps the blue.
IC 5146, Caldwell 19 · Emission nebula in Cygnus · magnitude 7.2 · 12′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 Cocoon 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
- Cocoon Nebula with the ZWO Seestar S50: 2 h 58 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S50 Pro: 3 h 20 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S30: 3 h 29 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S30 Pro: 3 h 36 min from Bortle 6
- Cocoon Nebula with the DwarfLab DWARF 3: 3 h 39 min from Bortle 6
- Cocoon Nebula with the DwarfLab Draco: 2 h 21 min from Bortle 6
- Cocoon Nebula with the DwarfLab DWARF II: 17 h from Bortle 6
- Cocoon Nebula with the Vaonis Vespera II: 4 h 49 min from Bortle 6
- Cocoon Nebula with the Vaonis Vespera Pro: 11 h from Bortle 6
- Cocoon Nebula with the Vaonis Vespera 3: 4 h 36 min from Bortle 6
- Cocoon Nebula with the Vaonis Vespera Pro 2: 10 h from Bortle 6
- Cocoon Nebula with the Unistellar eQuinox 2: 4 h 25 min from Bortle 6
- Cocoon Nebula with the Unistellar Odyssey: 21 h from Bortle 6
- Cocoon Nebula with the Celestron Origin: 1 h 16 min from Bortle 6
- Cocoon Nebula with the Celestron Origin Mark II: 1 h 44 min from Bortle 6
All telescopes for the Cocoon Nebula · All targets for the DWARF mini