197 
JUNE 4, 2000:
A Big 10 for Hubble
Have you seen the Hubble Telescope stamps? If you’d like to decorate your letters with astronomical images, then you might consider stopping by the post office and picking up a couple of souvenir sheets. There are twenty stamps, five unique images. NASA’s Hubble Space Telescope has simply been the best investment in astronomy that "We the People" could have ever made. Orbiting for 10 years nearly 375 miles above Earth’s ocean of murky and continuously moving air, Hubble has provided us with the clearest and most detailed images of astronomical objects to date. Named for Edwin Hubble, the American astronomer, who gave us our first quantitative picture of the expanding universe, Hubble continues to allow us to define that expansion more clearly than ever before. Hubble’s dramatic photographs have shown us a fragmented comet crashing into Jupiter, depicted the processes by which stars are born and die, and imaged the effects of black holes at the centers of massive galaxies. It has also raised questions about the mass and size of the universe. If you’d like to find out more about the HTS’s science results and the Next Generation Space Telescope being planned by NASA for launch in 2008, come to a free public lecture at Trinity Episcopal Church, 44 E. Market St., Bethlehem, Sunday, June 11, at 7 p.m. The presenter, Dr. John Wood, is the Lead Optics Engineer for HTS. Dr. Wood will discuss the science capabilities of Hubble, and will give examples of objects studied in our solar system, the Milky Way galaxy, as well as the youngest and most distant galaxies ever seen. Directions and a map locating Trinity Episcopal Church can be found at the web site below.
Where is Trinity Episcopal Church?
From Route 22:
- On Route 22 East or West
- Take the Exit for Rt. 378 South
- At Exit 3 (Center City) proceed to the Stop Sign and turn left onto 2nd Avenue
- Go to the stop light and take a left onto West Broad Street
- Go across the bridge and take a right at the stop light onto Main Street
- Go to the next stop light and take a left onto Market Street
- Trinity Church is on the right in the block between New and Center Streets
- Parking is available on the street and in the rear of the building
From Rt. 378 South (Quakertown, Upper and Lower Saucon)
- Take Rt. 378 North up and over South Mountain.
- Take Exit 1 onto Main Street
- Take a left at the light at the end of the bridge onto Main Street
- Take a right at the light from Main Street onto Market Street
- Trinity Church is on the right in the block between New and Center Streets
- Parking is available on the street and in the rear of the building
From the South East (Route 78, Hellertown, Coopersburg, etc.)
- Take exit 21 from Route 78 and go north on Rt. 412 (Hellertown Rd.)
- Follow Hellertown Road North and at the Y, bear right onto Daly Ave.
- Take a right at the light and cross the Minsi Trail Bridge
- Take the first left after crossing the bridge onto Market Street
- Trinity Church is on the left in the block between Center and New Streets
- Parking is available on the street and in the rear of the building
198 JUNE 11, 2000:
The Analemma
Have you ever seen that elongated figure eight on a globe? Usually placed in the Pacific Ocean away from any land masses, it is called the analemma. If you would observe the sun each day of the year, at let’s say noon, and start with the sun due south, you would see several effects. First, because the Earth axis is tilted, you would notice the height of the sun changing above the horizon. The sun would appear highest at summer solstice and lowest six months later at winter solstice. But another more subtle motion would be also be viewed. As the sun was changing its altitude, it would appear to move to the right and left of the due south position. In other words as the days passed, your watch would say 12 noon, but the sun might be to the left or right of due south. The combinations of the change in the height of the sun and its motion to the right or left of south would create the analemma in the sky. Our clocks beat to an average rhythm called mean solar time which has been standardized to time zones and then further modified to daylight saving time during the warmer months. Each day at noon (now 1 p.m.) an imaginary sun is due south by this convention. As the Earth revolves around the sun, it shifts the sun about one degree to the east each day. We correct for this by adding an extra four minutes to the Earth’s spin period to create the mean solar day. But the eastward shift of the sun is not uniform. This is because Earth’s orbital velocity changes due to its elliptical orbit. Also, the northward and southward component of the sun’s motion due to our axial tilt, causes the sun’s eastward motion to vary. The result may put the real sun ahead of our clocks by 16 minutes and behind by just over 14 minutes. See
www.analemma.com.
199 JUNE 18, 2000:
Starlight, not Streetlight
One of the aspects of living in an urbanized area such as the Lehigh Valley is our inability to view the nighttime sky. Perhaps at best, several hundred stars are visible to the unaided eye even from towns such as Emmaus, Macungie, and Nazareth, and far fewer from Allentown, Bethlehem, and Easton. The major culprit which keeps us from seeing more starlight is streetlight. Most it comes from poorly designed lighting fixtures which inadvertently direct this unwanted energy into the sky. A perfect example of this abuse can be seen from any airplane flying over a metropolitan area at night. Those sparkles of white and orange from countless streets and parking lots is wasted energy which is being directly transmitted into space. For the most part, this is the light that is killing our skies. The new lighting on Hamilton Street is about as bad as it can get. These lights not only illuminate the streets, but they equally light up the facades of all of the buildings in downtown Allentown. Why is it necessary to throw "streetlight" into a third floor apartment or for that matter straight up into the air? Plainly put, this is called light trespass and it could become a legal issue if someone were willing to fight it. Beyond the light which is directed most everywhere except down, the light also goes directly into one’s eyes causing unwanted glare which hampers the ability of the eye to see the stop signs at the crosswalks or pedestrians in the street. Although the lights look aesthetic during the day, they were a poor choice for a city burdened with too much debt and not enough sources of income. Who do you think is really paying the tab for all of this misdirected light which is hiding our stars?
200 JUNE 25, 2000:
Long Lunar Eclipse
On July 16th one of the best lunar eclipses of the century will be visible to the Pacific Ocean side of the world. New Zealand, Australia, and Japan will see the entire eclipse from start to finish. Hawaii sees totality centered around 4 a.m. For coastal California, the moon enters the Earth’s shadow about 4:55 a.m. about the time that the sky is beginning to brighten because of morning twilight. No portion of the eclipse will be visible for any of us in the Lehigh Valley. It may seem odd to write about an astronomical event which will not be seen from around here. However, summer is synonymous with travel, and there may be local readers in those parts of the world on the 16th who might want to witness this event. A number of factors make this eclipse special. At mid-totality which occurs at 3:56 a.m. Hawaiian Time, the moon will be nearly centered within the shadow of the Earth. In fact, it is the most central lunar eclipse in 76 years. The last time the moon was more centrally located occurred on July 26, 1953. The next time will be June 26, 2029. An even more centrally positioned lunar eclipse will occur in 2340. Furthermore, at the time of the July 16th lunar eclipse, the moon will have just passed apogee, its farthest distance from the Earth. This means that the moon will be moving at nearly its slowest orbital velocity. The moon’s motion against the background of stars will also be at its slowest, and the moon will take longer to pass through the shadow of the Earth. The maximum duration of totality for a lunar eclipse is 1 hour, 47 minutes. On July 16th the interval of totality will be only one minute less. Although most of us will not see this eclipse, it’s still fun to dream.
