The Sandoval Signpost

An Independent Monthly Newsmagazine Serving the Community since 1989

DARK SKIES

Science and astronomy fun for the entire family

Charlie Christmann

The Albuquerque Astronomical Society and the LoadStar Astronomy Center are presenting several events of interest to star lovers in the month of May.

On Saturday, May 3, The Albuquerque Astronomical Society and the Sandia Ranger District will be hosting Stargazing in the Manzanos. An assortment of large telescopes will be set up to view galaxies, nebulae, and star clusters under the dark skies of the East Mountains. The event is free to the public. Take highway 337 south from Tijeras. Go nine miles and follow the signs to Oak Flat and Juniper Loop. The fun begins at sunset. A map is available at www.taas.org. For more information, call 261-0040.

The big don’t-miss affair of May is the Astronomy Day Fair, celebrating National Astronomy Day in Tiguex Park, Old Town, Albuquerque, on Saturday, May 10, from 10:00 a.m. until 4:00 p.m. Admission is free. The Albuquerque Astronomical Society and the Loadstar Astronomy Center are your cohosts for this fun and educational event which includes safe viewing of the Sun through filtered telescopes, fun hands-on activities for kids, model rocket launches, computer slide shows, displays, handouts about astronomy and science, and numerous exhibitors. For more information, call 261-0040 or e-mail pr@taas.org.

The LoadStar Astronomy Center will present Mars ROVER on Saturday, May 17. This event will be of interest to families with children who are preschool to middle-school age. The focus is on the upcoming mission to Mars and the vehicle that will be used to explore the surface. The program will be held from 2:00 p.m. to 4:00 p.m. at the LoadStar Center, 1801 Mountain Road NW, in Albuquerque. Call 841-5970 for more information.

 

The May night sky

More and more people are migrating outside in the evenings for great stargazing. Turn out your lights and join your neighbors for the spectacle.

Anyone who sits outside in the evenings can’t help but notice the “Albuquerque glow.” In case you haven’t noticed, it’s that dome of orange light over the city of Albuquerque. Elsewhere, there is a light dome over Santa Fe, one over Rio Rancho, and, to a smaller extent, one over Casino Hollywood. Because of these light domes, we are losing our view of the night sky.

“Prosperity and cheap electricity have promoted a mindless disregard for lighting excess that needs to be brought to public attention." —Harrisburg Patriot-News Editorial

So, just how many stars should we able to see?

Astronomers estimate that the dimmest object a human can see in total darkness is about a magnitude 6.5. Magnitude is a measure of brightness: negative numbers are brighter and positive numbers are dimmer. Over the entire sky, there are 8,497 stars brighter than a magnitude 6.5. Naturally, not all of these are above the horizon. The atmosphere also fades the stars near the horizon because of the amount of air, dust, and pollution we must look through to see the stars there.

Taking these factors into account, a person should be able to see about twenty-five hundred stars at one time under perfect viewing conditions. All of these visible stars are in our galactic backyard; most are within a couple of thousand light years.

The closer you get to a major metropolitan area, the fewer stars are visible. In the outskirts of a large city, the dimmest star you can see will be about a magnitude 4.0 (remember, smaller numbers are brighter). This reduces the number of starts visible to about 250. At the city center, forget seeing anything below a magnitude 3.0. Now, we are down to fifty stars. In our brightest cities, like New York, Las Vegas, or Los Angeles, only magnitude 2.0 stars or brighter are viewable. These city residents are lucky to see fifteen stars in the sky.

". . . substantial amounts of electricity are consumed through unnecessary outdoor lighting by retail establishments after business hours, including but not limited to, shopping centers, auto malls and dealerships . . ." —Governor Gray Davis, California

The major contributors to light pollution in cities are unshielded street lights, billboard lights that point up, parking-lot lights, and signs. But outside the cities, in the country, there are many sources of light pollution. Spot lights, mercury-vapor yard lights, and even misdirected outside lights at homes.

Why should you be concerned? First, there is the glare. Glare occurs when you see light directly from the source bulb or fixture. Not only will this light pollute the night sky but it can hamper vision and create a hazard for motorists. Next is light trespassing. This is light that shines into neighbors’ homes through windows reducing privacy and hindering sleep. Then, consider the energy waste. Poorly-designed lighting reduces effectiveness by throwing light where it is not needed or wanted. Finally, upward-pointed lights create sky glow that washes out the night sky. Americans waste millions of dollars each year by using more light than is needed. They buy larger lights to illuminate more area than is needed.

  • So, here are a few suggestions.
  • Turn off outdoor lights when they are not being used.
  • Shield light fixtures so the light is directed down toward the ground.
  • Only light the area that needs it.
  • Get shielded mercury or sodium-vapor fixtures, or better yet, don’t use any.
  • Use floodlights sparingly and point then downward.
  • If you must have a light on, use a low-wattage bulb.
  • "The night sky is the world's largest national park with its stark beauty available to anyone who steps outside and looks up." —Geoff Chester, United States Naval Observatory

Thank you from all of the stargazers.

 

The disappearing Moon

Watch the Moon put on a show on May 15 with a total eclipse. The Earth’s shadow begins eating into the moon at 8:03 p.m. mountain time. Totality begins at 9:14 p.m.

A total eclipse begins when the Moon passes into the shadow of the Earth. The shadow is a circular cone eight thousand miles in diameter. It tapers off to nothing at a point 864,000 miles out in space. At the Moon’s orbit, Earth’s shadow is 5,700 miles in diameter. By chance, the Moon’s diameter is 2,160 miles and it moves in its orbit at 2,112 miles per hour. Thus, totality lasts about one hour as the Moon traverses the shadow. This is also the day of the Full moon.

This month offers us two new moons: on May 1 and May 31.

Where are the planets?

  • Watch for Mercury in the morning twilight late in May. Mercury will be just south of Venus on May 27.
  • Venus rises around 5:00 a.m.
  • Mars rises about 2:00 a.m. Check for Mars three degrees north of the Moon on May 21.
  • Jupiter sets at 1:00 a.m. Jupiter will be four degrees south of Jupiter on May 8.
  • Saturn sets at 11:00 p.m. Find Saturn three degrees south of the Moon on May 5.

 

 

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