Science & history · Star guide
Canopus, the second-brightest star
Canopus is the second-brightest star in the night sky, in the southern constellation Carina. From much of the Northern Hemisphere it never rises at all, which is why many people have never heard of it.
About this picture
NASA/Goddard Space Flight Center Scientific Visualization Studio. Gaia DR2: ESA/Gaia/DPAC. Constellation figures based on those developed for the IAU by Alan MacRobert of Sky and Telescope magazine (Roger Sinnott and Rick Fienberg). NASA's page (opens in a new tab).
The map is a composite of 1.7 billion catalogued stars, not a photograph from one place: it shows stars far too faint for the eye, and no weather, Moon or city light. It is drawn here in this chart's projection, with each star where it was in 2000; the fastest-moving bright star has shifted about a minute of arc since, far less than a pixel here.
How to spot it: About 36° south of Sirius: three and a half fists at arm's length. Source (opens in a new tab)
What you are looking at
Canopus is a rare yellow-white bright giant, far more luminous than Sirius but much farther away.
In the Hipparcos measurements Canopus is magnitude −0.62, second only to Sirius (opens in a new tab); ESA's table gives no distance for it. Jim Kaler (opens in a new tab) uses 309 light-years, from the second reduction of the Hipparcos data, with an uncertainty of about five percent.
Kaler (opens in a new tab) describes it as a rather rare class F yellow-white bright giant, with a surface of about 7,280 kelvin, some 13,300 times the Sun's luminosity and a radius around 71 to 73 times the Sun's. Its exact mass depends on its stage of life, but falls between 8 and 9 Suns.
It and Sirius only look like neighbours. Physically they have nothing to do with each other (opens in a new tab): Canopus is the far grander star, much farther away.
Sources for this section ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab); Jim Kaler, Canopus, STARS (University of Illinois) (opens in a new tab)
How to find it
Canopus lies about 36° south of Sirius, and never rises north of about 37°N.
Canopus lies about 36° south of Sirius (opens in a new tab). A fist held at arm's length covers about 10 degrees (opens in a new tab), so it is three and a half fists from Sirius toward the southern horizon.
By this site's calculation (opens in a new tab), Canopus never rises north of about 37°N. Kaler (opens in a new tab) spells out what that means: it is out of sight from Canada, almost all of Europe and half of the continental United States, but makes a grand sight with Sirius from the deep southern US and the whole Southern Hemisphere.
By the same calculation (opens in a new tab), from 35°S it climbs to about 72° up in the south, and it is highest at about 9 p.m. local time in mid-February.
Sources for this section Bright Star Catalogue, 5th Revised Ed. (Hoffleit & Warren 1991), as computed by this site's star engine (opens in a new tab); NASA Science, Skywatching FAQ (2024) (opens in a new tab); Jim Kaler, Canopus, STARS (University of Illinois) (opens in a new tab)
A spacecraft's guide star
NASA's Mariner probes to Mars held their orientation by locking onto the Sun and Canopus.
A spacecraft far from Earth needs fixed references to point by. NASA's Mariner probes to Mars used optical sensors that locked onto the Sun and Canopus (opens in a new tab); JPL explained that Canopus supplied a second reference, with the Sun, for the mid-course manoeuvre and for aiming the science instruments at Mars.
In 1969 Mariner 6's Canopus sensor was “distracted” by tiny bright dust particles (opens in a new tab) shaken off the spacecraft, and the craft rolled until it found the star again. Mariner 7, launched on 27 March 1969, spent its first five days locked onto Vega before commands from Earth sent it searching for Canopus.
Sources for this section NASA JPL, Mariner 7 to Complete Star Acquisition Sequence (1969) (opens in a new tab)
Where on Earth, and when
It rises from anywhere south of about 37°N.
South of about 37°S, it never sets.
It climbs at least 20° high, the finder's threshold for a suggestion, from anywhere south of about 17°N.
It is highest in the evening sky, at about 9 p.m. local time, in mid-February, from either hemisphere, wherever it rises. With daylight saving time, that is nearer 10 p.m. on the clock.
Worked out by this site from the Bright Star Catalogue, for a flat, clear horizon. Hills, buildings, haze and city light all cut into this; the air also lifts objects near the horizon by about half a degree. For your own place and night, use the sky finder.
Sources
- Astronomy ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab) for its magnitude and rank · checked 27 September 2026
- Astronomy Jim Kaler, Canopus, STARS (University of Illinois) (opens in a new tab) for its type, distance, size, luminosity, mass and where it can be seen · checked 2 October 2026
- Astronomy NASA Science, Skywatching FAQ (2024) (opens in a new tab) for the fist-width rule · checked 27 September 2026
- History NASA JPL, Mariner 7 to Complete Star Acquisition Sequence (1969) (opens in a new tab) for the Mariner Canopus sensors · checked 2 October 2026
- Astronomy Bright Star Catalogue, 5th Revised Ed. (Hoffleit & Warren 1991), as computed by this site's star engine (opens in a new tab) for its distance from Sirius on the sky, its northern limit, its height and best month
