Centaurus A

NGC 5128, Caldwell 77 · Galaxy in Centaurus

Magnitude: 6.8
Size: 26′ × 20′
Effective surface brightness: 21.7 mag/arcsec²
Best months: Mar, Apr, May
Declination: -43°
Filter: None (broadband target)

A giant elliptical with a thick dust band across it, the brightest radio galaxy in the sky. A southern-hemisphere showpiece.

Low or below the horizon from northern Europe; best from the southern US southwards.

How long with each smart telescope

Total integration for a solid image of the Centaurus A, default sub length, recommended filter, and how much of each frame it fills. Click a cell for the full Bortle 1 to 9 table.
Telescope	In frame	Bortle 3 (rural)	Bortle 5 (suburban)	Bortle 7 (urban edge)
ZWO Seestar S5010 s subs	60%	17 min102 subs	27 min160 subs	1 h 09 min412 subs
ZWO Seestar S50 Pro10 s subs	31%	19 min113 subs	29 min176 subs	1 h 15 min448 subs
ZWO Seestar S3010 s subs	36%	19 min114 subs	29 min172 subs	1 h 11 min424 subs
ZWO Seestar S30 Pro10 s subs	19%	20 min121 subs	31 min187 subs	1 h 19 min474 subs
DwarfLab DWARF 315 s subs	26%	23 min91 subs	37 min150 subs	1 h 42 min410 subs
DwarfLab DWARF mini15 s subs	36%	17 min68 subs	26 min106 subs	1 h 08 min274 subs
DwarfLab Draco30 s subs	35%	15 min30 subs	22 min44 subs	57 min114 subs
DwarfLab DWARF II15 s subs	24%	1 h 12 min290 subs	1 h 39 min397 subs	3 h 36 min864 subs
Vaonis Vespera II10 s subs	30%	17 min102 subs	27 min160 subs	1 h 09 min412 subs
Vaonis Vespera Pro10 s subs	27%	41 min247 subs	1 h 01 min368 subs	2 h 30 min898 subs
Vaonis Vespera 310 s subs	30%	16 min97 subs	25 min152 subs	1 h 06 min394 subs
Vaonis Vespera Pro 210 s subs	26%	39 min233 subs	58 min349 subs	2 h 23 min858 subs
Unistellar eQuinox 24 s subs	76%	22 min326 subs	28 min416 subs	54 min809 subs
Unistellar Odyssey4 s subs	77%	1 h 54 min1,713 subs	2 h 16 min2,040 subs	3 h 51 min3,469 subs
Celestron Origin10 s subs	51%	5 min30 subs	7 min41 subs	19 min113 subs
Celestron Origin Mark II10 s subs	58%	5 min31 subs	9 min55 subs	26 min158 subs

Open in the calculator

Imaging the galaxy

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.

Centaurus A

How long with each smart telescope

Imaging the galaxy

Per-telescope pages