Star-Hopping with the Big Dipper

One of the first things I can remember learning about astronomy was star-hopping using the Big Dipper. I learned this technique from illustrations in the 1952 book “The Stars: A New Way to See Them” by H.A. Rey – the creator of “Curious George.” I still have a copy of that book today.

Using the Big Dipper to find Polaris – the North Star. Credit:Stellarium/Bob Trembley

The Big Dipper is not a constellation, it is an asterism: a prominent pattern of stars, having a popular name, composed of stars from one or more constellations. The Big Dipper is an asterism in the constellation Ursa Major – “The Great Bear”

Big Dipper Asterism in Ursa Major. Credit: Stellarium/Bob Trembley

Ursa Major: The Great Bear. Credit: Stellarium/Bob Trembley

The Big Dipper can be used to star-hop all over the night sky; I find myself doing this unconsciously quite frequently.

Big Dipper Pointing to Arcturus and Spica. Credit: Stellarium/Bob Trembley

Big Dipper Pointing to Capella. Credit: Stellarium/Bob Trembley

Big Dipper Pointing to Regulus. Credit: Stellarium/Bob Trembley

Big Dipper Pointing to Castor. Credit: Stellarium/Bob Trembley

Ursa Major is host to numerous deep sky objects:

Deep Sky Objects in Ursa Major. Credit: Stellarium/Bob Trembley

M101 Location in Ursa Major. Credit: Stellarium/Bob Trembley

M101 – The Pinwheel Galaxy in Ursa Major. Credit: ESA/NASA/Wikimedia Commons

M51 Location in Ursa Major. Credit: Stellarium/Bob Trembley

M51 – The Whirlpool Galaxy. Credit: NASA/ESA/Wikimedia Commons

M81 and M82 Location in Ursa Major. Credit: Stellarium/Bob Trembley

M81 (left) and M82 (right) in Ursa Major: Credti: Wikimedia Commons

M97 – The Owl Nebula Location in Ursa Major. Credit: Stellarium/Bob Trembley

M97 – The Owl Nebula. Credit: © 2013 Mazlin from Star Shadows Remote Observatory (SSRO).

An interesting object in the handle of the Big Dipper is the naked eye double star Mizar and Alcor. When I was a younger, I could just barely see that there are two stars there; when giving night sky tours, I often challenge young observers to do the same. Mizar and Alcor are not gravitationally bound, rather they are nearly in line with each other when viewed from the Earth.

Mizar and Alcor Location in Ursa Major. Credit: Stellarium/Bob Trembley

In a small telescope Mizar and Alcor separate, and it becomes apparent that Mizar is itself a double star.

Mizar and Alcor in a Small Telescope. Credit: Stellarium/Bob Trembley

But that’s not all: Alcor is also a double star, and Mizar is a double double star!
https://youtu.be/oZBMeFIdtSE

Mizar and Alcor Gallery: