National Astronomical Observatory of Japan

Let’s Find Canopus! (February, 2017)

February, 2017, Sky time of Canopus’s Meridian Transit
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Best Time to Find Canopus!

It is the best time of the year to observe the 1st magnitude star Canopus in the constellation Carina. Canopus is a 1st magnitude star and it is also the second brightest star in the entire sky. However, in Japan it is known as a very difficult star to find because it is located low in the southern sky. In northern Japan, it doesn’t even rise above the horizon, so it can’t be seen. The calculated northern limit when observing from flatland is approximately 37.9° north latitude. That is roughly the northern Fukushima Prefecture region. In most areas of Japan, it can only be seen at low altitude just above the horizon, even when it crosses the meridian. Its altitude becomes higher the further south you are, making it easier to find.

Canopus is a white star. But, it looks dimmer and redder than it really is because it is located low in the sky and is affected by the Earth’s atmosphere. To search for Canopus, choose a clear night and a location with an unobstructed view of the southern horizon. Then, using the Great Winter Triangle and Sirius in the constellation Canis Major as guides, look down from Sirius towards the southern horizon to find Canopus appearing on the horizon. February is the best time to observe Canopus because it can be seen early in the night.

Maximum Elevation and Time of Meridian Transit
LocationMaximum ElevationTime of Meridian
Transit (Feb 1)
Time of Meridian
Transit (Feb 11)
Time of Meridian
Transit (Feb 21)
Naha11.2°22:0621:2720:47
Fukuoka3.9°21:5521:1620:36
Kyoto2.5°21:3420:5420:15
Tokyo1.9°21:1820:3819:59
Fukushima0.1°21:1520:3619:56

* The maximum elevations listed here include the effects of atmospheric refraction.