Edition 17 of the Astronomy On-line Newspaper

Collaborative projects

There have been further developments within a some of the Collaborative Projects.

1. Light Pollution

Dr. A. Haenel in Osnabrueck informs that a provisional report is available at http://www.physik.uni-osnabrueck.de/students/ahaenel/aol/lightpol.html.

2. The Solar Parallax

Prof. U. Backhaus in Koblenz has placed the final report for this project on the Web at http://www.uni-koblenz.de/~backhaus/aol/finalrep.htm.

3. The Size of the Earth

The Final Report is now available.

4. Solar Eclipse

We have received a report from Professor Jay Pasachoff (USA):

We have set up six photos and the following text on the following Web page: http://albert.astro.williams.edu/oct12eclipse.html.

I did not make measurements, but was probably the easternmost observer to watch and photograph the partial eclipse of October 12. It was the 24th solar eclipse that I have seen. I observed the eclipse from Jerusalem, Israel, from a site on the Mount of Olives. From that location, I could see the sun setting over the Old City of Jerusalem.

The sun set partially eclipsed. I could observe the eclipse for about 40 minutes, starting at 4:25 p.m., until it went into clouds five minutes before it reached the horizon. The maximum eclipse at sunset was about 30 percent.

I had hoped to be able to obtain a photograph showing the partially eclipsed sun over the Dome of the Rock, taking advantage of natural dimming of the sun at sunset. But there was enough dust in the air that scattering prevented the partially-eclipsed sun from being viewed without a solar filter. No matter how short an exposure I used without the filter, the solar shape could not be distinguished from the scattering dust. Similarly, the scattering prevented the pinhole images to be as clear as they sometimes are.

Photographs taken with a Nikon 500-mm f/8 lens and a Thousand Oaks Optical chromium-deposited solar filter came out satisfactorily.

Present with me on the Mount of Olives were Naomi Pasachoff (my wife) and Zviah Nardi (a cousin who drove us), a Reuters television cameraman and his assistant, an Arab who brings his camel there for tourists to pose with, and a few others. I have nice photos of the camel owner looking at the sun through solar filters I have provided and also making pinhole images. He is in traditional costume. I was able to provide a chromium filter for the Reuters TV cameraman, and his images were broadcast subsequently. I have a copy of clips from his videotape ineclipsed sun over the Dome of the Rock, taking advantage of natural dimming of the sun at sunset. But there was enough dust in the air that scattering prevented the partially-eclipsed sun from being viewed without a solar filter. No matter how short an exposure I used without the filter, the solar shape could not be distinguished from the scattering dust. Similarly, the scattering prevented the pinhole images to be as clear as they sometimes are.

Photographs taken with a Nikon 500-mm f/8 lens and a Thousand Oaks Optical chromium-deposited solar filter came out satisfactorily.

Present with me on the Mount of Olives were Naomi Pasachoff (my wife) and Zviah Nardi (a cousin who drove us), a Reuters television cameraman and his assistant, an Arab who brings his camel there for tourists to pose with, and a few others. I have nice photos of the camel owner looking at the sun through solar filters I have provided and also making pinhole images. He is in traditional costume. I was able to provide a chromium filter for the Reuters TV cameraman, and his images were broadcast subsequently. I have a copy of clips from his videotape in both PAL and NTSC Betacam format. I was also able to distribute Mylar filters from Thousand Oaks to various children and to others present.

I am glad to know that even a partial eclipse like this one was made into such a wonderful educational experience by your project.

Jay M. Pasachoff
Field Memorial Professor of Astronomy and Director of the Hopkins Observatory,
Williams College, Williamstown, Massachusetts 01267, USA
Chair, Working Group on Eclipses of the International Astronomical Union
Chair, Subcommittee on Eclipses of Commission 46 on the Teaching of Astronomy of the International Astronomical Union

5. Distance between the Earth and the Moon

Observations of the partially eclipsed Sun enabled Astronomy On-Line participants to emasure the distance between the Earth and the Moon. Here is a letter about the same problem, which was recently received from Joseph Ferris in Ireland:

I have been reading the Astronomy On-Line pages with interest concerning the European multipartner project to measure the distance between the Earth and the Moon. Our school is linked with a school in Wiesbaden, Germany and we have been developing a similar type of ongoing collaborative experiment to measure this distance using hand held sextants and taking simultaneous measurements of the altitude of the moon from our schools. Data is exchanged on a regular basis using e-mail.

Our results to date are very promising, but we are not ready to publish yet. You can get an idea of what we are up to by viewing our collaborative webpage at:

http://www.campus.bt.com/CampusWorld/orgs/org262/eartmoon/eartmoon.htm

(a version in German is being produced by my partner Ingo Heidelberg).

Our big problem is that our two schools are too close together (598 nm) and we are searching for a partner on more or less the same meridian of longitude but as far away as possible on the same side of the Earth......a school in South Africa would be perfect. Can you help us out in any way?

Joseph Ferris
Physics Master
St MacNissi's College
Garron Tower
Ireland
(email: JoeFerris@aol.com)


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Last update: Jan 27, 1997