StarWatch for the greater Lehigh Valley


162    OCTOBER 3, 1999:    Our Reality Is Always in the Past
Autumn is probably the best time to view the heavens, especially after our area has been invaded by a dome of dry, unpolluted Canadian air. It is the precursor of the much colder weather which is to follow. Star watching on a crisp fall evening allows us to glimpse our corner of the universe at many different time periods in the past. Our messenger for most of our astronomical knowledge is light, and in its broadest sense, this encompasses the entire array of energies known as the electromagnetic spectrum. Gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves are all part of the "information superhighway" that astronomers use to translate raw data into theory. All of this information travels to us at 186,000 miles/second. Thatís per second. It sounds really fast, but the universe is so huge that even this prodigious velocity is best described as a snailís pace when we talk about seeing the most distant objects. It may take 8-15 billion years for the most distant information to reach our telescopes. Thatís 8-15 billion light years away. Delays are shorter in our solar system. That sunset you witnessed last evening showed old Sol the way it was about eight minutes before it set. Bright Jupiter, in the east at 10 p.m., really was the way Jupiter looked a little before 9:30 p.m. And Saturn, below and to Jupiterís left, will appear the way it looked about 8:50 p.m. The light radiating from the North Star shows the way it appeared around 1570. By the time we reach out and observe the Andromeda Galaxy, we are now about two million years into the past. Thatís when you and I were a lot smaller, hairier, and dumber, but nevertheless, upward bound.
163    OCTOBER 10, 1999:     The Blob
UFOís! Millions of people claim to have seen them, but the evidence is slim that we are being visited by extraterrestrials. Still, there exists certain observed phenomena which lack good scientific explanations. Such was almost the case on a recent Dieruff Academy Field Experience to Chaco Culture National Historical Park. Itís located near the "back of beyond," about 150 miles to the northwest of Albuquerque, New Mexico, and it was the ancestral home of a thriving culture of native American Indians about 1000 years ago. Besides its archaeological treasures, Chaco boasts a modern observatory with two fine telescopes. Needless to say, itís heaven on Earth if you love astronomy, and thatís precisely what four members of our group were doing when a most unusual event occurred. It was Oct. 3rd at 9:00 p.m. Adam Kraynak of Breinigsville was the first to spot it, a glow in the west which looked at first like the full moon rising. The moon was not full that evening, and it rises in the east. Kraynak immediately alerted me to this unusual event, but I was slow to respond, figuring it could never be that bright. After all we were in the "Land of Enchantment." Wow, was I wrong! A large semi-circular shield of light bulged about 10 degrees above the western horizon, then faded over several minutes. Dozens of campers also saw it. It was a UFO until last Thursday, when Kraynak solved the mystery. The launch of a Minuteman II rocket from Vandenberg Air Force Base, NW of Santa Barbara, CA occurred at the same time. Its sky glow was reported as far east as Phoenix. Farther east, with darker skies at Chaco, it was also seen. We saw a rocket launch from 700 miles away. No X-Files here.
164    OCTOBER 17, 1999:    Purchasing a Telescope: Part 1
I have always put off thinking about the Holidays until after Thanksgiving. However, if youíre in the market to purchase a telescope, now is the time to start pondering your options. Here are some ideas to consider. Stay away from department store varieties. Youíll pay too much and probably get a piece of junk in return. In Allentown, Danís Camera City offers its customers a knowledgeable staff and a nice variety of choices. Contact them at 610-434-2313. Regionally, a much larger retailer exists about an hour north of the Valley. You can call Pocono Mountain Optics at 1-800-569-4323. PMO deals mainly in mail and phone orders, so donít expect lots of customer assistance, but they do have over 100 different scopes on display in their Moscow, PA showroom. Click on astronomy links from the home page below, then to Commercial Products/Software to get to the web sites of DCC and PMO. Here are a few tips to remember. If you are not willing to spend at least several hundred dollars on your new telescope, then invest your money in a good pair of binoculars. Keep in mind that a telescopeís main function is TO GATHER LIGHT, NOT TO MAGNIFY an image. Good telescopes are designed to gather a sufficient amount of light so that an object can be clearly seen at some reasonable magnification. Youíll probably get the biggest bang for your bucks if you purchase a reflecting telescope that uses mirrors to focus light rather than lenses. Unless you have money to burn, start with a smaller, instrument: a 2-4 inch refractor or a 4-8 inch reflector. You can always upgrade later. More about telescopes next week, or read ahead at the web site below.
165    OCTOBER 24, 1999:    Purchasing a Telesope: Part 2
Every telescope is a compromise. The type of instrument purchased should be based upon where you live, where you plan to conduct your observations, and what you enjoy observing the most. The aperture of a telescope simply represents the light-gathering element, either a series of lenses for a refractor, or mirrors for a reflector. Catadioptric systems incorporate both lenses and mirrors resulting in far greater portability, but higher costs. The focal length of a telescope is simply the distance that it takes light to come to a focus after being bent or reflected by the optical elements in its path. Divide the aperture into the focal length, and the focal ratio (F/ratio) results. Everything remaining equal, the longer the F/ratio, the higher will be your magnification. Keep in mind that 50 power per inch of aperture is a reasonable expectation for magnification. If you live in a city and plan to observe from an urban environment, then your options are limited because of light pollution. Concentrate on bright objects, such as the sun (with proper filtration), the moon, the planets, and double stars. Your best bet might be a 2-4 inch refractor with a focal ratio of F/9-15. If your penchant is for deep-sky objects such as galaxies, nebulae, star clusters, etc., or beautiful views of eclipses, consider a 4-8 inch, F/4 to F/7 reflector. You should live in a rural setting or be prepared to haul your equipment to such a location to maximize its potential. Accessories should include additional eyepieces so that you will have several choices of magnification. Youíll also need a star atlas, planisphere, or software package, so that you will have maps to help you identify what is currently visible in the sky.
166    OCTOBER 31, 1999:    Mercury Transits Sun
It last happened on November 10, 1973, and itís going to happen again near sundown on Monday the 15th. Tiny Mercury is transiting the sun. A transit occurs when a smaller astronomical object or shadow passes in front of or across a more distant larger body. You might call a solar eclipse a transit, expect that both the moon and the sun appear to be the same size. The Mercury transit is not going to be an easy observation for several reasons. First, the event begins at 4:12 p.m. when the sun is nearly setting. You will have to have a nearly flawless western horizon and, of course, clear skies in that direction. November produces few clear days. Second, youíll need to either telescopically project the sun onto a screen or view it through a filtration system in tandem with a telescope. Telescopes that produce high magnifications are preferable. Go to the astronomy links section on my home page below and click on eclipses. Choose Viewing a Partial Solar Eclipse for more viewing tips including solar safety. If you imagine the sun to be a clock, by 4:30 p.m. on the 15th, Mercury will appear at the 1 p.m. position, very close to the limb (edge) of the sun. Mercury will be small, only about 1/200th the diameter of the sun, but it will be very black making it easier to view than if a sunspot were in the same location. Another problem will be the way that your telescope orients Mercury with the horizon. Some telescopes reverse left and right, as well as invert the image. In that case look at the 7 p.m. position of the sun. If you have no luck there, then check the 5 p.m. and the 11 p.m. positions. Mercury has only transited 13 other times this century, so the effort may be worth risking, even if the chances of success are slim.
October Star Map
October Moon Phase Calendar