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A Solar Eclipse

On February 26th, southern New Englanders will have a chance to glimpse the last total eclipse visible from the Americas in this century. The eclipse will be total only on the north west corner of South America where it joins the Isthmus of Panama. For everyone else who see it, this eclipse will be partial. By my calculations, the eclipse starts in southern New England around 12:30 PM and the last trace disappears about 2:10 PM. At its maximum (around 1:23 PM, we will see the Sun with a small nibble (about 22%) taken from its lower edge by the Moon.

Let me WARN EVERYONE not to view the eclipse directly! Under no circumstances should you attempt to directly use improperly shielded telescopes or binoculars. Permanent blindness can occur in less than the blink of an eye when one of these instruments is focused on the Sun. Some people think that exposed photographic film is safe for viewing by eye. It isn't! Even the blackest color film allows half the dangerous infrared rays to pass through. Some older cheap telescopes came with eyepiece filters. All telescope eyepiece filters are extremely dangerous! The Sun overheats the eyepiece filters until they shatter, blinding the viewer with intense solar radiation. Only main objective filters covering the opening to a telescope should be used, and then only by adults who know what they are doing.

Having warned you about dangerous ways to view an eclipse, let me suggest a perfectly safe, fun way to view an eclipse. Use a camera obscura. "What?" you say, "I don't have a handy camera obscura. In fact I've never even heard of one." Well, camera obscuras have long since been replaced by photographic cameras, but they are very easy to make. All you need is a tube a few inches in diameter (mailing tubes and ornamental wrapping paper tubes are fine), some tin foil, and some tissue paper. Pull the tin foil and tissue taut over each end of the tube and secure them with rubber bands. Make a tiny neat pin hole in the center of the tin foil. Voila! Instant camera obscura.

Hold your rig steady with the tin foil pin hole end to the Sun. On the tissue paper, you will see the image of the Sun. It is perfectly safe to view this way. My camera obscura is about four feet long and produces an image of the Sun about a half inch wide. Shorter tubes will produce smaller brighter images and longer tubes will produce larger dimmer images. The thinner the tissue paper the better the quality. I have experimented with other methods, but all in all this method seems to be the easiest and the best for a one time event.

Moving on to other events, the evening sky has only Saturn left from the parade of planets that filled the Fall months. Venus is a brilliant beacon in the East, for early risers. Jupiter is setting just after the Sun this month. Mars is just behind Jupiter but very faint. The other planets are lost in the Sun's glare.

The Moon pulls off another spectacular stunt on the evening of March 4th. It will "eclipse" (occult is the official astronomical term) the bright star Aldebaran in the constellation of Taurus (the Bull). My calculations for the Westerly area are that Aldebaran will slide behind the dark limb of the Moon at 7:44 PM until it reappears on the bright side of the Moon about 8:29 PM. The Moon will be just slightly less than full (46%) this evening. Finding Aldebaran will be easy this evening, it will be the bright star near the Moon.

Orion remains the dominant constellation with its host of wonders (see last month's article). The constellations making their first appearance of the year in the early evening sky are Gemini with its pair of famous twins Castor and Pollux and Leo (the Lion, a sickle shaped group of stars) featuring its brilliant star Regulus. Tucked in between them is faint little Cancer (the Crab). A bit to the South are Monocerus (the Unicorn) and the big and little dogs Canis Major and Canis Minor with their brilliant stars Sirius and Procyon. Sirius is that very bright star in the southern sky. It outshines any other star we can see in southern New England by a factor of 3½ times. I'll have more to say about the brightness and the colors of stars in another article, but for now I'll wish everyone good viewing.

Leslie Coleman
Author:
Leslie Coleman
Entry Date:
Feb 1, 1998
Published Under:
Leslie Coleman's Columns
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