Canopus - Visibility

Visibility

In the southern hemisphere, Canopus and Sirius are both visible high in the sky simultaneously, and reach the meridian just 21 minutes apart. It is a circumpolar star when seen from points that have latitude south of 37°18' south; for example, Victoria and Tasmania, Australia; Auckland and south of it, New Zealand; Bahía Blanca, Argentina; and Valdivia, Chile and south of these cities in South America. Since Canopus is so far south in the sky, it never rises in mid- or far-northern latitudes; in theory the northern limit of visibility is latitude 37°18' north. This is just south of Athens, Richmond (USA), and San Francisco, and very close to Seville. It is almost exactly the latitude of Lick Observatory on Mt. Hamilton, California, from which it is readily visible due to the effects of elevation and atmospheric refraction, which add another degree to its apparent altitude. Under ideal conditions it has been spotted as far north as latitude 37°31' from the Pacific coast. It is more easily visible in places such as the Gulf Coast and Florida, and is best viewed around 9 p.m. on February 6.

Most visible in the southern hemisphere summer, Canopus culminates at midnight on December 27, and at 9PM on February 11.

F-type supergiants have been described as yellow-white or white. Canopus has a B-V color index of 0.16 where 0 is a blue-white, indicating it is essentially white, although has been described as yellow-white. Its spectral type has been recorded as either F0 or sometimes A9. It has less yellow than Altair or Procyon, whose color indexes have been measured at 0.22 and 0.42 respectively. Author Fred Schaaf has proposed that some observers have seen it yellow-tinged due to it being located low in the sky and hence an atmospheric effect.