Speaker: Fritz Kleinhans, PhD, Assoc. Prof. Emeritus - Physics, IUPUI, Scientech Club member
Introduced By: Rick Whitener
Attendance: NESC:103, Zoom: 47
Guest(s): Bernie Pierce, Nancy Snively, Bernice Schabler, Phil Bremen, Susie Bremen, Garry Vesahlik
Scribe: Fritz Kleinhans
Editor: Ed Nitka
View a recording of today’s Zoom presentation at:
Today's Program 031124
Fritz Kleinhans began with a brief introduction to eclipse photography with a long lens. Several key points were to - automate the process, practice on the everyday sun (partial eclipse proxy) and the moon (total eclipse proxy), use exposure bracketing, shoot raw files, and nail focus. Look at the list of included URL’s (attached at end) for some good eclipse photo sites. Kleinhans recommends most folks concentrate on visually observing the eclipse. It is easy to get wrapped up in photography and ‘miss’ the eclipse. Plus, the eye is much better at seeing the eclipse phenomena than a camera. The eye-brain system has a much better dynamic range and contrast detection ability.
The eclipse can and should be experienced with all your senses. It is a visceral experience. To be sure, you need know nothing to enjoy the eclipse. But with a little knowledge, a better understanding is possible and a lot more can be seen.
There are three kinds of eclipses: Partial, annular, and total. During a partial eclipse, the moon never fully covers the sun. During an annular eclipse, the moon is too far away to fully cover the sun and an annulus of light is observed around the moon. And during a total eclipse, the sun is fully covered. Of course, for a total eclipse, there is a partial phase before and afterward. During partial phases, eye protection must be used (eclipse shades), but during totality all filters are removed and the naked eye or binoculars are used to observe.
Any given total eclipse can only be observed over a long thin strip of the earth’s surface. Eclipses always start at the western end of the strip and end on the eastern end. The moon’s shadow takes several hours to traverse this strip and travels at thousands of miles per hour. Eclipse diagrams often mention Universal Time (UT) which is just the standard time in Greenwich, England. EDT = UT – 4 hrs. Totality can last from seconds to seven minutes. However, to experience the longest duration of totality one has to be close to the center line of the strip of totality. If one gets close to the edge, a briefer totality is experienced. To compute times for your exact location, use this Google interactive map:
https://eclipsewise.com/solar/SEgmapx/2001-2100/SE2024Apr08Tgmapx.html
Several motions are involved in the eclipse phenomena. The earth’s rotation causes everything to swing across the sky from east to west. Superimposed on this motion is the monthly motion of the moon around the earth. This causes the moon to slowly slide across the sun from west to east (right to left) during the eclipse. The whole process takes a few hours, but totality only last minutes. However, for our coming eclipse there will be no totality if you do not have clear sky overhead. It is strongly recommended to learn the use of NOAA satellite imagery to track where clear sky is to be found on eclipse day. Do not be afraid to drive a few hours (Try leaving the eclipse path, drive toward your destination, and then re-enter the eclipse path to minimize traffic.)
Eclipse observation points: A list of eclipse phenomena was handed out. Here is a nice list on the internet: https://www.space.com/10-phenomena-to-see-and-photograph-april-total-solar-eclipse-2024
Kleinhans recommends observing the eclipse with a crowd of people. The energy of the crowd enhances the experience.
Then – to see:
- First contact when the moon takes its first nibble out of the sun (about 1:50 pm in Indy).
- Eclipse crescents beneath trees and anything acting like a pin hole camera.
- Eerie light by 2:30 pm.
- Bright planets visible by 15 min before totality (Venus and Jupiter).
- Shadow bands sometime between 2 min before totality and totality (these are faint rippling shadows on the ground – use a white sheet).
- Light level begins to drop dramatically. Temperature drop may be noticeable.
- Nearly totality: Baily’s beads are the last beams of sunlight passing through lunar valleys.
- Diamond ring: The inner corona makes a ring around the moon and the last
beam of sunlight makes a ‘diamond’.
- Totality begins: About 3:06 PM in Indy. The sun is fully covered. The beautiful
corona bursts into view. This is the most impressive sight during the eclipse. Use your binoculars.
Also visible are prominences: jets of red gas reaching a short way out from the edge of the (moon) sun.
Totally will last about 3 ½ to 4 minutes in the Indy area.
- Totality is followed by another Diamond Ring and then Baily’s Beads. Time to put your binoculars down and put your eclipse shades back on.
- Many folks worry about damaging their eyes if they use their binoculars or plain eyes for too long!! I have watched the end of the last several eclipses using Canon 15 x 45 IS binoculars. I can assure you, the end of the eclipse is obvious and you will have plenty of time to put your binoculars down before any eye damage occurs.
- Hooked? Our next two eclipse chances are Greenland (Aug 2026) and Spain and North Africa (Aug 2027).
- See a useful list of URL’s and smart phone apps below:
Fritz Kleinhans
