Night Sky April 2004
—Charlie Christmann
Step outside forty-five to ninety minutes after sunset between now and April 2 for a sight you can not see again until April 2036. The five brightest naked-eye planets will be simultaneously in view in the early evening sky.
Here is a quick guide to this spectacular event:
Mercury is much lower and less bright than brilliant Venus, but it should nevertheless be easy to find as it follows the sun down in the western sky. On the evening of April 1, look for it about forty-five minutes after sunset, shining at magnitude +0.6. Fading rapidly to magnitude +1.6 and setting much earlier each night, this planet will become difficult to see by April 5.
Only the Moon outshines Venus in the night sky. Venus is now as high as it ever gets for evening viewers at mid-northern latitudes, remaining up for about four hours after the Sun goes down. On the evenings of April 2 and 3 it will be less than one degree from the brightest Pleiad, third-magnitude Alcyone, in the Pleiades cluster. The glare from brilliant Venus will almost overwhelm it.
Mars has moved into the constellation Taurus, the Bull. It stands high in the west-northwest at dusk and sets around 11:30 p.m. As April gets underway, Mars will be located between the V-shaped Hyades and Pleiades star clusters. It is hard to believe that this was the same object that made headlines last August when it passed so near to the Earth and outshone everything in the night sky except for the Moon and Venus!
Look for Saturn high in the east-southeast sky at dusk. It sets about 1:00 a.m. Small telescopes continue to provide a wonderful view of Saturn’s beautiful ring system.
The giant gas planet, Jupiter, shines as a brilliant silvery "star" in Leo low in the eastern sky as dusk arrives. It is unmistakably the brightest star or planet in the region of sky it inhabits. In addition to Jupiter’s prominent cloud belts, the smallest telescope—even steadily held seven-power binoculars—will reveal the four bright satellites of Jupiter as tiny stars nearly in line and changing place in the line as they revolve around the planet in orbits nearly edgewise to us. On April 2, the Moon slides near Jupiter. The giant planet will appear as a bright star shining to the Moon’s right.
You may have heard about the football-field-sized chunk of rock that just missed Earth in the middle of March. The asteroid missed Earth by a slim 26,500 miles, passing over the southern Atlantic Ocean. That's just beyond the 22,300 mile orbit where the geostationary weather and communications satellites reside. In the thirty-one hours it took for the asteroid, named 2004 FH, to traverse the moon’s orbit, it was deflected fifteen degrees by Earth’s gravity.
Objects of this size pose a small threat to us. If this one had been a direct hit, it would most likely have exploded in the atmosphere, astronomers say. The result could have caused local damage.
This was a lucky find for astronomers, who have trouble seeing objects this small. For the past decade, asteroid hunters have focused on finding the larger asteroids, those that could cause global damage. They are not set up to spot all of the smaller objects that inhabit the same general space as Earth. There could be millions. As of March 18, there are 583 objects known as potentially hazardous. New ones are found all the time. To be on the list, the object must be larger than three hundred feet in diameter and pass closer than 4.5 million miles to Earth. None are currently known to be on a collision course with Earth.
Amateur astronomers may be rewarded for helping to find potentially hazardous asteroids. In March, the U. S. House of Representatives voted 404-1 to reward amateurs $3,000 for discovering and tracking near-Earth asteroids. Don’t try and collect just yet; the Senate and the President must still approve the bill.
If you have a question that I might be able to answer in an upcoming issue of the Signpost, or just want to make a comment, my e-mail address is sandovaldarksky@yahoo.com.
Sandoval County drafts ordinance to protect night sky
—Charlie Christmann
Sandoval County is actively working to add its name to the growing list of New Mexico counties and cities with an ordinance protecting our night sky. The need for this type of protection is obvious for our larger cities, but the consequences of inaction are only now being realized in rural areas.
A look into the night sky from the middle of Albuquerque shows the effect that light pollution has on the night sky: most of the stars are missing. Away from the city, the sky is full of stars. Yet the number of stars visible in rural Sandoval county pales in comparison to the truly dark skies found in the back country of Wyoming and Alaska.
Viewed from cities and nearby suburbs, the stars are fading away. What you are seeing is light pollution. Light pollution is a glow in the atmosphere caused by excess light shining out and up, where it is wasted. It comes from sources, such as street lights, billboards, signs, and many types of home outdoor light fixtures.
From miles away, Albuquerque creates an enormous dome of light that blots out the stars over the city. Look toward the nearest casino, too. They have a glow above them from the parking lot lights and signs. These cut out a slice of the night sky.
But there are solutions to the light-pollution problem which allow us to light the areas we need illuminated while saving energy costs. Newer cutoff fixtures are the answer to this and other problems created by poorly chosen fixtures.
There are other problems associated with poorly designed lighting: light trespass and glare.
Light trespass is a serious complaint by many who live near poorly designed outdoor lighting. Parking lots, service stations, streetlights, and yard lights are the worst offenders. However, home exterior lights and floodlights left on all night are also high on the complaint list. People trying to light their yards and driveways choose fixtures that allow the light to escape into their neighbors’ yards and windows. This type of lighting can be just as annoying as a loud stereo played late at night or the city’s all-night street construction.
Glary lights are a hazard to everyone. Glare happens when light shines directly into your eyes, like an oncoming car with high beams. It is very difficult to see the traffic lights, roadway, lane boundaries, and even pedestrians with the high beams in your eyes. In yards, glare can actually reduce security by not allowing us to see past the light into the shadows. As a rule of thumb, if you can see the lightbulb, it is causing glare.
Sandoval County is interested in protecting our night sky and eliminating light trespass. According to Mike Scales of Sandoval Zoning Enforcement, the county is currently drafting an ordinance to protect the night.
Sandoval County is not the first to see the need for this type of ordinance. Albuquerque now has an ordinance and is phasing in the requirements. Bernalillo County has put rules in effect for North Albuquerque Acres and the East Mountain area. Santa Fe, Taos, Alamogordo, Cloudcroft, and several other municipalities also have ordinances in place.
Planning and zoning would like Sandoval County to be added to list of those with an ordinance. Any ordinance proposed must be straightforward, easy to enforce, and control light trespass into adjacent properties.
To learn more about saving our night sky, the International Dark-Sky Association Web site at www.darksky.org is a good resource. If you would like to see what other New Mexico cities and counties have done, DeLapp & Associates has compiled a listing at http://delapp.com/codes/.
Your thoughts and suggestions on this ordinance are important. Please e-mail any comments to Charlie Christmann at sandovaldarksky@yahoo.com. They will be forwarded to the planning and zoning department for consideration.
National Dark Sky Week 2004
National Dark Sky Week (NDSW) will be held from April 19 to 26 this year. This event was founded by Jennifer Barlow, a high school student in Virginia, to temporarily reduce light pollution, while raising awareness about the effect of light pollution on the night sky.
The event encourages better lighting and promotes an interest in astronomy. The most important way to participate is to turn off unnecessary lighting. NDSW is the perfect opportunity to host a star party, visit an observatory, get the telescope out of the attic, learn more about the universe, and simply reconnect with the night sky. It is crucial to build participation by spreading the word about NDSW. For more information, visit the NDSW home page at www.ndsw.org.
|
