Ursa Major- the great bear

Ursa Major or the great bear is a large constellation in the northern hemisphere which contains many amazing wonders, from galaxies to meteor showers. as well as this Ursa Major plays a key role in locating North, by leading the way to the north star Polaris, in the nearby constellation of ursa minor. Ursa Major never sets in the northern hemisphere so is visible all year round.


photo credit: earthsky.org

 Ursa major is well known for containing the asterism, the big dipper. It is often used to locate the Northern star, Polaris. It is found by imagining a line between the stars Merak and Dubhe and then extending this line five times the distance of these two pointer stars, until a bright star is reached. This is the north star Polaris.

Ursa major is also home to a famous binary star system containing two stars called Mizar and Alcor. These two stars form an optical binary stat system which means that they aren’t gravitationally related, but appear to be close to each other in the sky. Mizar and Alcor are sometimes known as the horse and rider. also it is said that being able to see Alcor with the naked eye is a sign of good eyesight, although in reality even people with poor eyesight can see the pair.

 Ursa major is also a great constellation for those interested in the deep sky objects. It contains several spectacular galaxies including the Pinwheel galaxy or M101.

pinwheel galaxy

M101 is a face on spiral galaxy that is much larger than our own galaxy, the milky way, as it is 70% larger than the milky way. This galaxy contained a supernova explosion in 2011 which reached a peak magnitude of 9.9. 

The owl nebula is another deep sky object worth viewing. It is a planetary nebula, named so not because it has anything to do with planets but because when they were first discovered they were mistaken for planets, that is 1, 630 light years away from earth. It has a magnitude of around 10 so a large telescope will be necessary to view it.

Ursa Major is also the apparent source of a newly discovered meteor shower, the Kappa Ursae Majorids, which peak between the 1st and 10th of November each year.

There are a few stars in Ursa Major that have been discovered to hold extra solar planets, such as the star HD80606 which is home to at least one planet, which has been shown to be a possible hot Jupiter in the future. Hot Jupiter’s are extra solar planets which have similar characteristics to Jupiter but have much higher surface temperatures due to their closer proximity to the sun.