How long to image the Fireworks Galaxy with the DwarfLab DWARF 3
From a Bortle 6 suburban sky, the DwarfLab DWARF 3 needs about 7 h 37 min (1,829 subs of 15 s) for a solid image of the Fireworks Galaxy. A quick look takes 1 h 54 min; a showpiece 30 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 28 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it fills 11% 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 min118 subs | 1 h 58 min472 subs | 7 h 51 min1,886 subs |
| Bortle 2Typical dark site | 32 min129 subs | 2 h 08 min514 subs | 8 h 33 min2,053 subs |
| Bortle 3Rural | 37 min148 subs | 2 h 28 min592 subs | 9 h 52 min2,368 subs |
| Bortle 4Rural / suburban transition | 49 min196 subs | 3 h 16 min783 subs | 13 h3,132 subs |
| Bortle 5Suburban | 1 h 08 min272 subs | 4 h 31 min1,086 subs | 18 h4,343 subs |
| Bortle 6Bright suburban | 1 h 54 min458 subs | 7 h 37 min1,829 subs | 30 h7,314 subs |
| Bortle 7Suburban / urban transition | 3 h 23 min811 subs | 14 h3,244 subs | 54 h12,976 subs |
| Bortle 8City | 5 h 40 min1,361 subs | 23 h5,442 subs | 91 h21,766 subs |
| Bortle 9Inner city | 11 h2,532 subs | 42 h10,128 subs | 170+ h40,512 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 9 h 54 min of run time. That is more than one night: over 2 nights, about 4 h 57 min each. The DWARF 3’s battery is rated at about 5 h 30 min, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time.)
- 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.
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Everything that fits the DWARF 3 →
How it frames
The Fireworks Galaxy is 11′ × 10′ across. The DWARF 3 frames 2.93° × 1.65° at 2.75″ per pixel, so it fills 11% of the frame’s short side.
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 | 2 h 28 min592 subs | 4 h 31 min1,086 subs | 14 h3,244 subs |
| 30 s | 2 h 17 min275 subs | 4 h 21 min522 subs | 13 h1,601 subs |
| 60 s | 2 h 12 min132 subs | 4 h 15 min256 subs | 13 h795 subs |
Leave the dual-band filter out for the Fireworks Galaxy. It is a galaxy, and it shines right across the spectrum. A dual-band filter keeps two emission lines and throws the rest away, so most of the light you came for is being stopped along with the sky. From a Bortle 6 sky it would be roughly 10 times slower.
About the Fireworks Galaxy
A face-on spiral famous for its supernovae, dimmed by Milky Way dust. Faint arms; the open cluster NGC 6939 sits nearby.
NGC 6946, Caldwell 12 · Galaxy in Cygnus · magnitude 9.6 · 11′ × 10′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
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 Fireworks Galaxy from a DWARF 3? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Fireworks Galaxy with the ZWO Seestar S50: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S50 Pro: 5 h 45 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S30: 5 h 32 min from Bortle 6
- Fireworks Galaxy with the ZWO Seestar S30 Pro: 6 h 06 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF mini: 5 h 14 min from Bortle 6
- Fireworks Galaxy with the DwarfLab Draco: 4 h 19 min from Bortle 6
- Fireworks Galaxy with the DwarfLab DWARF II: 18 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera II: 5 h 15 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro: 12 h from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera 3: 5 h 01 min from Bortle 6
- Fireworks Galaxy with the Vaonis Vespera Pro 2: 11 h from Bortle 6
- Fireworks Galaxy with the Unistellar eQuinox 2: 4 h 49 min from Bortle 6
- Fireworks Galaxy with the Unistellar Odyssey: 22 h from Bortle 6
- Fireworks Galaxy with the Celestron Origin: 1 h 23 min from Bortle 6
- Fireworks Galaxy with the Celestron Origin Mark II: 1 h 54 min from Bortle 6
All telescopes for the Fireworks Galaxy · All targets for the DWARF 3