How long to image the Crab Nebula with the DwarfLab Draco
From a Bortle 6 suburban sky, the DwarfLab Draco needs about 22 min (45 subs of 30 s with the built-in dual-narrowband (Hα + OIII) filter) for a solid image of the Crab Nebula. A quick look takes 6 min; a showpiece 1 h 30 min. Under a Bortle 3 rural sky the solid figure drops to 17 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 8% 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 | 5 min10 subs | 17 min34 subs | 1 h 06 min133 subs |
| Bortle 2Typical dark site | 5 min10 subs | 17 min34 subs | 1 h 07 min135 subs |
| Bortle 3Rural | 5 min10 subs | 17 min35 subs | 1 h 08 min137 subs |
| Bortle 4Rural / suburban transition | 5 min10 subs | 18 min36 subs | 1 h 12 min144 subs |
| Bortle 5Suburban | 5 min10 subs | 19 min39 subs | 1 h 17 min154 subs |
| Bortle 6Bright suburban | 6 min12 subs | 22 min45 subs | 1 h 30 min180 subs |
| Bortle 7Suburban / urban transition | 7 min15 subs | 29 min58 subs | 1 h 54 min229 subs |
| Bortle 8City | 9 min19 subs | 38 min76 subs | 2 h 32 min304 subs |
| Bortle 9Inner city | 15 min30 subs | 58 min117 subs | 3 h 52 min465 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 29 min of run time. The Draco’s battery (rated about 5 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 December night.)
- USB-C PD power bank 20000mAhRated 5 h on its 10,000 mAh battery. DwarfLab has not published the charging input, so check PD support before relying on it mid-session.
- 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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How it frames
The Crab Nebula is 6′ × 4′ across. The Draco frames 1.66° × 1.24° at 1.46″ per pixel, so it fills 8% of the frame’s short side.
Longer subs
Auto Mode picks the exposure; Pro Mode allows up to 300 s, held by built-in guiding and field derotation. The 30 s default here is our assumption. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 30 s | 17 min35 subs | 19 min39 subs | 29 min58 subs |
| 60 s | 30 min30 subs | 30 min30 subs | 30 min30 subs |
| 120 s | 1 h30 subs | 1 h30 subs | 1 h30 subs |
| 300 s | 2 h 30 min30 subs | 2 h 30 min30 subs | 2 h 30 min30 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 15 min30 subs | 21 min43 subs | 51 min103 subs |
| dual-narrowband (Hα + OIII) | 17 min35 subs | 19 min39 subs | 29 min58 subs |
About the Crab Nebula
The remains of the supernova of 1054, a tangle of filaments around a pulsar. Small but bright enough for a good result in an evening.
M1, NGC 1952 · Supernova remnant in Taurus · magnitude 8.4 · 6′ × 4′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Supernova remnants are emission-line objects, strong in both hydrogen-alpha and OIII, and their filaments are thin, so pixel scale matters as much as aperture. A dual-band filter is essential from any lit sky and still helps under a dark one. These are long-integration targets; plan on several sessions and stack across nights.
About the DwarfLab Draco
DwarfLab’s big scope: 90 mm of folded f/3.8 optics, the most aperture of any Seestar or DWARF, a narrow 13 nm dual-band filter and 300 s subs with built-in guiding. A small-target scope; big nebulae need its mosaic mode.
Auto Mode picks the exposure; Pro Mode allows up to 300 s, held by built-in guiding and field derotation. The 30 s default here is our assumption. Built-in Hα + OIII dual-narrowband filter, 13 nm per line; the SHO Edition adds an SII option.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 30 s and 300 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 Crab Nebula from a Draco? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Crab Nebula with the ZWO Seestar S50: 28 min from Bortle 6
- Crab Nebula with the ZWO Seestar S50 Pro: 31 min from Bortle 6
- Crab Nebula with the ZWO Seestar S30: 31 min from Bortle 6
- Crab Nebula with the ZWO Seestar S30 Pro: 33 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF 3: 37 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF mini: 28 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF II: 2 h 08 min from Bortle 6
- Crab Nebula with the Vaonis Vespera II: 38 min from Bortle 6
- Crab Nebula with the Vaonis Vespera Pro: 1 h 25 min from Bortle 6
- Crab Nebula with the Vaonis Vespera 3: 37 min from Bortle 6
- Crab Nebula with the Vaonis Vespera Pro 2: 1 h 21 min from Bortle 6
- Crab Nebula with the Unistellar eQuinox 2: 34 min from Bortle 6
- Crab Nebula with the Unistellar Odyssey: 2 h 32 min from Bortle 6
- Crab Nebula with the Celestron Origin: 10 min from Bortle 6
- Crab Nebula with the Celestron Origin Mark II: 14 min from Bortle 6
All telescopes for the Crab Nebula · All targets for the Draco