How long to image the California Nebula with the DwarfLab DWARF 3
From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 2 h 28 min (591 subs of 15 s with the built-in dual-band filter) for a solid image of the California Nebula. A quick look takes 37 min; a showpiece 9 h 51 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 30 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 1.6× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 21 min85 subs | 1 h 24 min338 subs | 5 h 38 min1,351 subs |
| Bortle 2Typical dark site | 22 min87 subs | 1 h 26 min346 subs | 5 h 45 min1,382 subs |
| Bortle 3Rural | 23 min91 subs | 1 h 30 min361 subs | 6 h1,441 subs |
| Bortle 4Rural / suburban transition | 25 min99 subs | 1 h 39 min396 subs | 6 h 36 min1,583 subs |
| Bortle 5Suburban | 28 min114 subs | 1 h 53 min453 subs | 7 h 32 min1,809 subs |
| Bortle 6Bright suburban | 37 min148 subs | 2 h 28 min591 subs | 9 h 51 min2,364 subs |
| Bortle 7Suburban / urban transition | 53 min214 subs | 3 h 34 min856 subs | 14 h3,421 subs |
| Bortle 8City | 1 h 19 min317 subs | 5 h 16 min1,266 subs | 21 h5,062 subs |
| Bortle 9Inner city | 2 h 14 min536 subs | 8 h 55 min2,141 subs | 36 h8,563 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 12 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, and 30% off the battery for a December night.)
- 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.
- 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 3 →
How it frames
The California Nebula is 160′ × 40′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it is 1.6× 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 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 | 1 h 30 min361 subs | 1 h 53 min453 subs | 3 h 34 min856 subs |
| 30 s | 1 h 17 min154 subs | 1 h 40 min200 subs | 3 h 20 min401 subs |
| 60 s | 1 h 10 min70 subs | 1 h 33 min94 subs | 3 h 14 min194 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| Astro (no light-pollution filter) | 1 h 32 min368 subs | 2 h 47 min669 subs | 8 h 16 min1,985 subs |
| dual-band | 1 h 30 min361 subs | 1 h 53 min453 subs | 3 h 34 min856 subs |
About the California Nebula
A long, faint hydrogen streak near Menkib, nearly three degrees end to end. Needs a wide field and a dual-band filter; it is almost invisible in broadband.
NGC 1499 · Emission nebula in Perseus · magnitude 6.0 · 160′ × 40′ · best in Nov, Dec, Jan. 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 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 California 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
- California Nebula with the ZWO Seestar S50: 2 h from Bortle 6
- California Nebula with the ZWO Seestar S50 Pro: 2 h 15 min from Bortle 6
- California Nebula with the ZWO Seestar S30: 2 h 20 min from Bortle 6
- California Nebula with the ZWO Seestar S30 Pro: 2 h 25 min from Bortle 6
- California Nebula with the DwarfLab DWARF mini: 1 h 58 min from Bortle 6
- California Nebula with the DwarfLab Draco: 1 h 35 min from Bortle 6
- California Nebula with the DwarfLab DWARF II: 11 h from Bortle 6
- California Nebula with the Vaonis Vespera II: 3 h 13 min from Bortle 6
- California Nebula with the Vaonis Vespera Pro: 7 h 14 min from Bortle 6
- California Nebula with the Vaonis Vespera 3: 3 h 05 min from Bortle 6
- California Nebula with the Vaonis Vespera Pro 2: 6 h 53 min from Bortle 6
- California Nebula with the Unistellar eQuinox 2: 2 h 57 min from Bortle 6
- California Nebula with the Unistellar Odyssey: 14 h from Bortle 6
- California Nebula with the Celestron Origin: 51 min from Bortle 6
- California Nebula with the Celestron Origin Mark II: 1 h 10 min from Bortle 6
All telescopes for the California Nebula · All targets for the DWARF 3