Canes Venatici--
Who Let the Dogs Out?
….Harry Bearman


Bootes' two hunting dogs, "Starry" and "Dear", he holds on a leash keeping them from leaping upon the Great Bear. Known to us today as Canes Venatici, they hold dozens of interesting objects. According to one of my atlases, there are over 30 galaxies within the reach of a 8" or 10" telescope, and one spectacular globular cluster.

The most well known is the Whirlpool Galaxy, M51, first discovered by Charles Messier in October 1733, while observing a comet. Eight years later, his friend Pierre Mechain noted that it was double. (It's companion is NGC 5195.) M51 was also the first in which spiral structure was ever noted. Lord Rosse (William Parsons) first noticed this in the spring of 1845 while using his 72" reflector. At first this was thought to confirm Laplace's hypothesis of solar system formation. It wasn't until 1923 that spiral nebula were determined to be external galaxies, and far more distant than imagined.

The brightest star, Alpha Canes Venaticorum, is also known as Cor Caroli, Latin for "Heart of Charles". The source of this name has been argued. Legend has it that Edmund Halley named this to honor his benefactor, England's Charles II, though there are arguments that  it's actually Charles I that's being honored, he having been beheaded by Oliver Cromwell, on Jan 30, 1649. By the way, the monarchy was formally abolished a week later. That didn't last long though, Oliver died in 1658, the monarchy was reestablished, and three years after he died he was beheaded. Yes, you read that right.

Y Cvn is an interesting variable star, a red "carbon" star, known as La Superba, according to the AAVSO, it varies from 5.2 - 6.6 over a 158 day period.

Another of the interesting galaxies in Canes Venatici is NGC 4151. A type of galaxy called a Seyfert, this is one of the brightest ones of its kind known. Spectroscopically they differ considerably from normal galaxies. Among the strange things about them is that their cores typically outshine the rest of the galaxy, and is variable over a period of typically less than a year. More can be read about them at http://www.astro.soton.ac.uk/PH308/AGN/Seyferts.html.