How long to image the Cone and Christmas Tree with the DwarfLab Draco
From a Bortle 6 suburban sky, the DwarfLab Draco needs about 3 h 09 min (378 subs of 30 s with the built-in dual-narrowband (Hα + OIII) filter) for a solid image of the Cone and Christmas Tree. A quick look takes 47 min; a showpiece 13 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 04 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 80% 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 | 29 min59 subs | 1 h 58 min236 subs | 7 h 50 min941 subs |
| Bortle 2Typical dark site | 30 min60 subs | 2 h240 subs | 7 h 59 min959 subs |
| Bortle 3Rural | 31 min62 subs | 2 h 04 min248 subs | 8 h 16 min992 subs |
| Bortle 4Rural / suburban transition | 33 min67 subs | 2 h 14 min268 subs | 8 h 56 min1,072 subs |
| Bortle 5Suburban | 37 min75 subs | 2 h 30 min300 subs | 10 h1,200 subs |
| Bortle 6Bright suburban | 47 min95 subs | 3 h 09 min378 subs | 13 h1,512 subs |
| Bortle 7Suburban / urban transition | 1 h 06 min132 subs | 4 h 23 min527 subs | 18 h2,108 subs |
| Bortle 8City | 1 h 35 min190 subs | 6 h 19 min759 subs | 25 h3,033 subs |
| Bortle 9Inner city | 2 h 36 min313 subs | 10 h1,252 subs | 42 h5,007 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 06 min of run time. The Draco’s battery is rated at about 5 h, less near freezing, so the session 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 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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Everything that fits the Draco →
How it frames
The Cone and Christmas Tree is 60′ × 30′ across. The Draco frames 1.66° × 1.24° at 1.46″ per pixel, so it fills 80% 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 | 2 h 04 min248 subs | 2 h 30 min300 subs | 4 h 23 min527 subs |
| 60 s | 1 h 27 min88 subs | 1 h 53 min114 subs | 3 h 47 min227 subs |
| 120 s | 1 h 09 min35 subs | 1 h 35 min48 subs | 3 h 29 min105 subs |
| 300 s | 2 h 30 min30 subs | 2 h 30 min30 subs | 3 h 18 min40 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 1 h 53 min226 subs | 3 h 18 min396 subs | 9 h 29 min1,138 subs |
| dual-narrowband (Hα + OIII) | 2 h 04 min248 subs | 2 h 30 min300 subs | 4 h 23 min527 subs |
About the Cone and Christmas Tree
A bright cluster shaped like a tree with the faint Cone Nebula at its tip and the Fox Fur beside it. The cluster is easy; the nebulosity is not.
NGC 2264 · Emission nebula in Monoceros · magnitude 3.9 · 60′ × 30′ · 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 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 Cone and Christmas Tree from a Draco? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Cone and Christmas Tree with the ZWO Seestar S50: 4 h from Bortle 6
- Cone and Christmas Tree with the ZWO Seestar S50 Pro: 4 h 30 min from Bortle 6
- Cone and Christmas Tree with the ZWO Seestar S30: 4 h 43 min from Bortle 6
- Cone and Christmas Tree with the ZWO Seestar S30 Pro: 4 h 51 min from Bortle 6
- Cone and Christmas Tree with the DwarfLab DWARF 3: 4 h 52 min from Bortle 6
- Cone and Christmas Tree with the DwarfLab DWARF mini: 3 h 56 min from Bortle 6
- Cone and Christmas Tree with the DwarfLab DWARF II: 23 h from Bortle 6
- Cone and Christmas Tree with the Vaonis Vespera II: 6 h 37 min from Bortle 6
- Cone and Christmas Tree with the Vaonis Vespera Pro: 15 h from Bortle 6
- Cone and Christmas Tree with the Vaonis Vespera 3: 6 h 19 min from Bortle 6
- Cone and Christmas Tree with the Vaonis Vespera Pro 2: 14 h from Bortle 6
- Cone and Christmas Tree with the Unistellar eQuinox 2: 6 h 05 min from Bortle 6
- Cone and Christmas Tree with the Unistellar Odyssey: 28 h from Bortle 6
- Cone and Christmas Tree with the Celestron Origin: 1 h 45 min from Bortle 6
- Cone and Christmas Tree with the Celestron Origin Mark II: 2 h 23 min from Bortle 6
All telescopes for the Cone and Christmas Tree · All targets for the Draco