How long to image the Centaurus A with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 2 h 19 min (557 subs of 15 s) for a solid image of the Centaurus A. A quick look takes 35 min; a showpiece 9 h 17 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 12 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 24% 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 | 16 min66 subs | 1 h 06 min264 subs | 4 h 23 min1,054 subs |
| Bortle 2Typical dark site | 17 min69 subs | 1 h 08 min273 subs | 4 h 33 min1,091 subs |
| Bortle 3Rural | 18 min73 subs | 1 h 12 min290 subs | 4 h 50 min1,159 subs |
| Bortle 4Rural / suburban transition | 21 min83 subs | 1 h 23 min331 subs | 5 h 31 min1,324 subs |
| Bortle 5Suburban | 25 min100 subs | 1 h 39 min397 subs | 6 h 36 min1,586 subs |
| Bortle 6Bright suburban | 35 min140 subs | 2 h 19 min557 subs | 9 h 17 min2,228 subs |
| Bortle 7Suburban / urban transition | 54 min216 subs | 3 h 36 min864 subs | 14 h3,453 subs |
| Bortle 8City | 1 h 24 min335 subs | 5 h 35 min1,339 subs | 22 h5,353 subs |
| Bortle 9Inner city | 2 h 27 min588 subs | 9 h 48 min2,352 subs | 39 h9,407 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 01 min of run time. The DWARF II’s battery is rated at about 3 h, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time.)
- 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.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the DWARF II →
How it frames
The Centaurus A is 26′ × 20′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 24% of the frame’s short side.
About the Centaurus A
A giant elliptical with a thick dust band across it, the brightest radio galaxy in the sky. A southern-hemisphere showpiece.
NGC 5128, Caldwell 77 · Galaxy in Centaurus · magnitude 6.8 · 26′ × 20′ · best in Mar, Apr, May. Low or below the horizon from northern Europe; best from the southern US southwards.
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 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 Centaurus A from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Centaurus A with the ZWO Seestar S50: 41 min from Bortle 6
- Centaurus A with the ZWO Seestar S50 Pro: 45 min from Bortle 6
- Centaurus A with the ZWO Seestar S30: 43 min from Bortle 6
- Centaurus A with the ZWO Seestar S30 Pro: 48 min from Bortle 6
- Centaurus A with the DwarfLab DWARF 3: 1 h from Bortle 6
- Centaurus A with the DwarfLab DWARF mini: 41 min from Bortle 6
- Centaurus A with the DwarfLab Draco: 34 min from Bortle 6
- Centaurus A with the Vaonis Vespera II: 41 min from Bortle 6
- Centaurus A with the Vaonis Vespera Pro: 1 h 32 min from Bortle 6
- Centaurus A with the Vaonis Vespera 3: 39 min from Bortle 6
- Centaurus A with the Vaonis Vespera Pro 2: 1 h 27 min from Bortle 6
- Centaurus A with the Unistellar eQuinox 2: 37 min from Bortle 6
- Centaurus A with the Unistellar Odyssey: 2 h 49 min from Bortle 6
- Centaurus A with the Celestron Origin: 11 min from Bortle 6
- Centaurus A with the Celestron Origin Mark II: 15 min from Bortle 6
All telescopes for the Centaurus A · All targets for the DWARF II