How long to image the Thor's Helmet with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 36 h (8,572 subs of 15 s) for a solid image of the Thor's Helmet. A quick look takes 8 h 56 min; a showpiece 140+ h. Under a Bortle 3 rural sky the solid figure drops to 17 h. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 7% 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 | 3 h 53 min931 subs | 16 h3,722 subs | 62 h14,888 subs |
| Bortle 2Typical dark site | 4 h 02 min968 subs | 16 h3,871 subs | 65 h15,484 subs |
| Bortle 3Rural | 4 h 20 min1,039 subs | 17 h4,153 subs | 69 h16,611 subs |
| Bortle 4Rural / suburban transition | 5 h 02 min1,209 subs | 20 h4,836 subs | 81 h19,342 subs |
| Bortle 5Suburban | 6 h 10 min1,480 subs | 25 h5,918 subs | 99 h23,670 subs |
| Bortle 6Bright suburban | 8 h 56 min2,143 subs | 36 h8,572 subs | 140+ h34,288 subs |
| Bortle 7Suburban / urban transition | 14 h3,408 subs | 57 h13,631 subs | 230+ h54,522 subs |
| Bortle 8City | 22 h5,372 subs | 90 h21,485 subs | 360+ h85,937 subs |
| Bortle 9Inner city | 40 h9,559 subs | 160+ h38,235 subs | 640+ h152,937 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 46 h of run time. That is more than one night: over 7 nights, about 6 h 38 min each. The DWARF II’s battery is rated at about 3 h, less near freezing, so each night needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a January night.)
- USB-C PD power bank 10000mAh 18W18 W PD input; runs while charging.
- 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 II →
How it frames
The Thor's Helmet is 8′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 7% of the frame’s short side.
Filters
The Thor's Helmet is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the DWARF II has no dual-band option: Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold. The figures above are for the Astro position, and a darker sky is the lever that remains.
About the Thor's Helmet
A Wolf-Rayet bubble with wings, strong in OIII. Small and faint; dual-band is essential and a bigger scope helps.
NGC 2359 · Emission nebula in Canis Major · magnitude 11.5 · 8′ · best in Dec, Jan, Feb. 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 II
The original pocket scope. 24 mm aperture and tiny 1.45 µm pixels mean it is slow per pixel, so bin or downsample and be patient.
15 s is the hard maximum in any mode; DwarfLab recommends EQ mode at 15 s. Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold.
The DWARF II uses fixed 15 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.
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 Thor's Helmet from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Thor's Helmet with the ZWO Seestar S50: 6 h 17 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S50 Pro: 7 h 04 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S30: 7 h 24 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S30 Pro: 7 h 38 min from Bortle 6
- Thor's Helmet with the DwarfLab DWARF 3: 7 h 41 min from Bortle 6
- Thor's Helmet with the DwarfLab DWARF mini: 6 h 11 min from Bortle 6
- Thor's Helmet with the DwarfLab Draco: 4 h 58 min from Bortle 6
- Thor's Helmet with the Vaonis Vespera II: 10 h from Bortle 6
- Thor's Helmet with the Vaonis Vespera Pro: 23 h from Bortle 6
- Thor's Helmet with the Vaonis Vespera 3: 9 h 53 min from Bortle 6
- Thor's Helmet with the Vaonis Vespera Pro 2: 22 h from Bortle 6
- Thor's Helmet with the Unistellar eQuinox 2: 9 h 31 min from Bortle 6
- Thor's Helmet with the Unistellar Odyssey: 44 h from Bortle 6
- Thor's Helmet with the Celestron Origin: 2 h 44 min from Bortle 6
- Thor's Helmet with the Celestron Origin Mark II: 3 h 44 min from Bortle 6
All telescopes for the Thor's Helmet · All targets for the DWARF II