Double star Albireo, at the head of Cygnus the Swan.
Credit: Conrad Jung, through Chabot’s 8-inch telescope, Leah.
I occasionally get an email or a phone call from someone wanting to know what that strange, dazzling light was they saw in the sky that looked too unusual to be a star, or a planet, and was certainly not an airplane…

Whenever this happens, I think back to a night in my youth when the same sort of thing happened to me. I was in my early teens, living under the relatively “dark” skies of Alamo, in the shadow of Las Trampas Regional Park. I walked outside and looked up to the sky to see a dazzling light, one that I swore I’d never seen before.

Its sheer brightness was enough to make me do a double take, but the way it flickered and flashed in every color or the rainbow– red, blue, green, maybe a glint of yellow– made me wonder if I were seeing a supernova, and if I should run inside and report it to someone.

As it turned out, it was the star Sirius, in the constellation Canis Major, to the left of Orion– and though it’s a member of a winter constellation, you can still see it, low in the southwestern sky after dusk. Sirius is the brightest star in our sky–after the Sun of course– with enough intensity in its light for the color-sensing “cone” cells in our eyes’ retinas to register. The prismatic flashing of different colors you can see in Sirius is caused by its light being refracted in Earth’s atmosphere and the various colors being split apart, like light passing through a prism.

Though there are some other stars bright enough to show their true colors to our human eyes– such as “red giant” stars like Antares, Betelgeuse, and Arcturas– most stars are only detected by our more sensitive “rod” cells, which paint pictures in our brains in shades of gray. The fact of the matter is that the night sky is full of color– it’s just too subtle for our eyes to perceive.
Telescopes, even small ones, can bring out the colors in objects in space, collecting enough light to stimulate our color vision or to allow a camera to capture a color image. The subtle colors of the night sky begin to reveal themselves, from the blue-whites and yellows and oranges of stars to the pinks of clouds of hydrogen gas (nebulas) to the soft blue-greens in distant planets like Uranus and Neptune.

You can check out our colorful universe as seen though Chabot Space & Science Center’s large telescopes at http://www.chabotspace.org/vsc/observatory/astrophotos.asp, or come up on a public viewing night on Friday or Saturday to look through the telescopes with your own eyes.

There’s a whole universe waiting to be noticed every time you step outside at night. It was Sirius that got me hooked on star gazing–after the surprise of its brightness and the colors in its light had passed. Before it disappears into the twilight of spring and summer, take a look to the southwest after dusk and see what you think…

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

Colors of Night 12 June,2013Ben Burress

Author

Ben Burress

Benjamin Burress has been a staff astronomer at Chabot Space & Science Center since July 1999. He graduated from Sonoma State University in 1985 with a bachelor’s degree in physics (and minor in astronomy), after which he signed on for a two-year stint in the Peace Corps, where he taught physics and mathematics in the African nation of Cameroon. From 1989-96 he served on the crew of NASA’s Kuiper Airborne Observatory at Ames Research Center in Mountain View, CA. From 1996-99, he was Head Observer at the Naval Prototype Optical Interferometer program at Lowell Observatory in Flagstaff, AZ.

Read his previous contributions to QUEST, a project dedicated to exploring the Science of Sustainability.

Sponsored by

Become a KQED sponsor