A close-up of Virgo
Keep Your Skies Dark
It is no secret that the stars in the night sky are disappearing. No, the stars are still there, it’s just that their faint glow can’t compete with the light pollution from city street lights or the glare of your next-door neighbor‘s “security lighting.”
Under unspoiled, pristine viewing conditions, a person with average eyesight should be able to see stars down to a +6.5 visual magnitude. Over the entire sky—north, south, night, and day skies—there are 8,479 stars at least that bright. Remember, stars with smaller or negative numbers are brighter—the brightest star, Sirius, is a -1.4 magnitude. So, on a given night, over your home, you could see about twenty-five-hundred stars.
Now, as we get closer to civilization and its lights, the numbers start to dwindle. In the vicinity of a city, you might be able to see stars brighter than a +4.0 magnitude. This equates to about 250 stars. Get to the suburbs, and the lights drown out all but about twenty-five stars. In large city cores, you’ll be lucky to find a dozen actual stars in the night sky.
So, just how dark are the night skies in your neighborhood? An easy test is to look for Polaris, the “north star.” Polaris is a second (+1.97) magnitude star. The tip of the handle in the little dipper (Ursa Minor) is Polaris. Follow the handle down to the bowl. If you can see all four stars in the bowl, you have a good dark night sky and you can see stars down to at least fifth (+5.0) magnitude. Find the two stars in the front of the bowl. These two stars, Kochab and Pherkad, are known as the Guardians of the Pole because they march around Polaris like sentries. If you can only find these two stars, your night skies are not very dark.
If you are concerned about our disappearing night sky, see the International Dark Sky Association’s website at darksky.com and get active in protecting this beautiful tableau we call our night sky.
Twilight under the portal at
“From the Beginning” is the theme of the Coronado State Monument 2009 Summer Lecture Series.
May 9 at 7:30 p.m., the first presentation in the series will be “Sayota—the Man from Heaven.” There is no admission fee for this event. Refreshments will be provided by the Friends of Coronado State Monument. The Monuments is located at 485 Kuaua Road, west of the town of Bernalillo, off I-25 on Highway 550.
A public stargaze
On Saturday, May 30, the Rio Rancho Astronomical Society will host its monthly meeting at Coronado State Monument starting at 8:00 p.m. A public stargaze will follow the meeting, weather permitting, and telescopes provided by RRAS members will provide stunning views of planets and other objects in the night sky.
For more information, log on to www.rrastro.org or call 220-5492.