StarWatch for the greater Lehigh Valley


075    FEBRUARY 1, 1998:   February 26th Solar Eclipse
A rare, astronomical treat is in store for us in February. On Thursday the 26, most of the United States will have the opportunity of witnessing a partial solar eclipse. The word "eclipse" means to hide or cover. The type of eclipse, in this case solar, indicates which object is to be hidden. The Sol (Latin for sun) will be partially hidden by the moon. The Galapagos Islands, parts of northern South America and the Caribbean, will experience a total solar eclipse, meaning that the moon will completely obscure the sun. The landscape or ocean will appear to be bathed in an eerie deep twilight for about three minutes as the moon’s shadow sweeps past. For the Lehigh Valley the partial solar eclipse begins at 12:28 p.m. and ends at 2:05 p.m. At mid-eclipse, 1:17 p.m., the moon will appear to take a dainty cookie bite from the sun when just over 20 percent of old Sol will be hidden from view. Improperly watching the partial phases of a solar eclipse, can lead to serious retinal burn and possible blindness. There are however, many completely safe and inexpensive techniques for viewing the sun during an eclipse. These methods will be examined in subsequent weeks. You can read ahead in the StarWatch section of the ASD Planetarium’s home page or click on the "eclipse" icon for even more in-depth coverage. Save this StarWatch for future reference.
076    FEBRUARY 8, 1998:   Eclipse Viewing with Welder's Filters
On February 26, there will be a partial solar eclipse visible to Valley residents between 12:28 p.m. and 2:05 p.m. NEVER, NEVER use sunglasses, multiple pairs of sunglasses, smoked glass, colored negative or chromogenic (silverless) b/w negative films, polarizing filters, colored cellophane, colored filters, neutral density filters, or sun filters that screw into the eyepiece lens of inexpensive telescopes and can break because of heat build up. All are potentially dangerous. So what can you use? A perfectly safe and effective device is a #14 Welder’s filter. The least expensive kind will produce a green image, but a gold covered one will create a very pleasant yellow sun. Any welding supply store such as J. W. S. Technologies in Allentown can supply these two different types of filters in two different sizes: 2x4 and 4x5 inches. Prices range from $1.60 to $10.95 per filter. Call them at 610-266-1500. Most sizes must be ordered, and it takes about one week for delivery. Welder’s filters are additive, which means that any combination which adds up to 14 will be safe. Welding goggles can also be purchased. These accommodate the smaller filter sizes. Read lots more about eclipses and how to observe the February 26 event at the Planetarium’s web site address found below.

Composite photo by Allen Seltzer, using a #14 green welder's filter.

J.W.S. Prices for #14 Welder's Filters

Item DescriptionSizesPrice/Unit
#14 Welder’s Shade2-inch by 4-inch$1.60
#14 Welder’s Shade4-inch by 5-inch$4.05
#14 Gold Welder’s Shade2-inch by 4-inch$5.55
#14 Gold Welder’s Shade4-inch by 5-inch$10.95
Welding Goggles/standard2-inch by 4-inch filters$7.95
Welding Goggles/filter flips2-inch by 4-inch filters$9.95
077    FEBRUARY 15, 1998:   Projected Solar Images
Here are some more tips about viewing the February 26 partial solar eclipse which will be visible from our area between 12:28 p.m. to 2:05 p.m. Use a telescope or binoculars as an optical projection system by pointing it at the sun and allowing the sunlight which it collects to pass through an eyepiece and project onto a piece of white cardboard. Do not try to locate the sun by looking directly through the telescope or binoculars. Instead, find the sun by manipulating the instrument so that the shadow of the tube presents the smallest possible surface area on the ground. Adjust the eyepiece focuser to sharpen the projected image. Be sure to shade the projection screen with a baffling device constructed around the telescope tube (for refractors) or binoculars. The baffle will shade the screen and increase the contrast of the sun’s image. If you are using binoculars, cap one of the sides or alternate which side is capped to prevent heat build up which may damage the optics. As a matter of safety, make sure that all finderscopes are either removed or covered and never leave your telescope unattended. See illustrations to these techniques or read up on other effective ways of observing this eclipse at the Planetarium’s web site found below.

Projecting the sun's image with a refracting telescope.

Michael Stump projects the sun's image with a
reflecting telescope. Gary A. Becker photo...

078    FEBRUARY 22, 1998:   Where to View the Eclipse
The partial solar eclipse of February 26 is almost upon us, and you still haven’t gotten your equipment together to safely watch the sun! The eclipse begins for Allentown about 12:28 p.m. and continues through 2:05 p.m. Where can you go to observe it? There are several stations which are being set up throughout the Lehigh Valley area. Check out Dieruff High School, 815 N. Irving St., Allentown, by the flagpole between 12:15 and 2:15 p.m.--phone 820-2200. Several telescopes hosted by Jesse Leayman and Louis Correa will be projecting the sun’s image, weather permitting. Bring your camera along and you can photograph the screen and take home a souvenir of the event. Dan’s Camera City, 1439 W. Fairmont St., Allentown will also have several telescopes pointed skyward from about noon to 2:30 p.m. Contact Tim Miller at 434-2313. Dan’s is also marketing Eclipsers, aluminized mylar glasses to safely view the sun. Their cost is $1.95. All proceeds benefit the ASD Planetarium. The next partial solar eclipse visible to residents of the Lehigh Valley occurs at sunrise on August 11, 1999, followed by a more impressive partial eclipse of the sun on Christmas day of the year 2000. Save your Eclipsers for these events also.

[ECLIPSE 01:55]
[ECLIPSE 01:17]
[ECLIPSE 12:38]

The Feb. 26, 1998 solar eclipse from Allentown (right to left): 12:38 p.m., 01:17 p.m., 01:55 p.m.

February Star Map