Sunflower Galaxy (M63)
A spiral galaxy in Canes Venatici, named for the many short arms its photographs show. Maps of its starlight and its gas weigh what it shines with: about a fifth of that is still gas, the raw material for new stars.
Galaxy in Canes Venatici. Magnitude 8.6.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 55° above the northern horizon at its highest; from Lethem (3.4° N), to 52° above the northern horizon. It is highest at midnight on the night of 8 Apr, in the middle of its season. The page works out tonight's rise, highest point and set for both towns in Guyana time (UTC-4), and where the Moon is.
What you'll see
- Your eyes: Not visible to the eye. It lies 5.3° north-east of Cor Caroli.
- 10x50 binoculars: A faint smudge from a dark site.
- A small telescope (80 to 100 mm): A bright oval core in a fainter halo about 1.7 times as long as wide; its arms need a larger telescope and a dark sky.
- A camera: Tiny on camera: it needs 2,000 mm or more of focal length on a tracking mount.
How big, how bright, how far
- Size on the sky: 11.8′ × 7.2′, 38% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 8.6. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 30 million light-years. The light reaching your eye left it about 30 million years ago.
- True size: 100,000 light-years across its catalogued outline; light crosses it in 100,000 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Spiral galaxy
Measured: What its visible mass is made of: stars and gas, not dark matter.
- Stars: 78.2%, from its infrared light
- Atomic gas: 15.6%, hydrogen, from 21 cm radio maps
- Molecular gas: 6.2%, from carbon monoxide maps
Each mass is given to a tenth of a dex, so each share is good to about a quarter of itself. Dark matter is not counted. Leroy et al. 2008, AJ 136, 2782, Table 4 (VizieR J/AJ/136/2782), NGC 5055: log stellar mass 10.8, atomic gas 10.1, molecular gas 9.7 (Suns). Shares do not depend on the distance the paper adopted.
Also in it, not measured:
- Spiral arms: lit by young stars
- Dark matter halo: not in this tally; seen only by its gravity
How we know: Distance from its brightest red giants (the tip of the red giant branch): NED-D (NASA/IPAC Extragalactic Database, redshift-independent distances), median of 2 TRGB estimates: 9.09 Mpc, 8.87-9.32 Mpc; e.g. 2017AJ....154...51M, 2015AstL...41..239T; retrieved 2026-10-21. True size: the apparent size times the distance (apparent size: OpenNGC (Mattia Verga, CC BY-SA 4.0), commit 4e2398a2).
More deep-sky objects: M94 (Galaxy) · Whirlpool Galaxy (M51) · Galaxy M106 · Pinwheel Galaxy (M101) · M109 (Galaxy) · Needle Galaxy (NGC 4565)