Solar eclipse - What science can you do?

A fake??? really ??, and where do 2 clocks come into it, I thought they measured star positions during totality and compared them to a previous non eclipse image?

The 1919 experiment not a fake,it was a triumph of science.

Any half baked astrophotographer can repeat it using today's equipment.

I think Dave you mean the one I mentioned that was attempted in the 1800's.

ok confusions reigns, so we talking about 2 different experiments here.
Whats the one you're on about Seanie?

Hmm ... now I'm a little confused. There would have been no relativity experiment at any eclipse in the 1800s because the theory hadn't been suggested at the time!

Is the 1800s reference to do with Jansen and Lockyer's measurements of the corona and the final nail in the coffin that prominences were huge mountains on the Moon? Jansen escaped Paris by balloon as it was under siege by the Austrian army at the time (1871 eclipse I think?). Lockyer subsequently identified the element helium in the solar spectrum.

The coelostat used by the African expedition at the 1919 eclipse is in the Meridian Room of Dunsink Observatory in north Dublin! A small card explains it's historical significance but most people aren't even aware it's there :roll:

Anyway, back to the topic and what science can be done at a total solar eclipse ...

Well, apart from lugging tons of equipment to test theories (or, as in recent times, search for intra-Mercurial planets), the eclipse chaser becomes more tuned to the many aspects of a solar eclipse the more they see

Study the shape of the corona as Dave mentioned. Also, during totality look for any structure in the corona -- I noticed whorls of material in the corona during the 1999 event. The structure at the Sun's poles is also worth noting.

The sky colours are well worth making note of. The beautiful hues during the 2006 eclipse was my highlight -- enhanced by banks of cloud on the horizon. I don't think any artists palette could reproduce the range of colours in the 2006 eclipse.

Observe the reaction of the flora and fauna in the run-up to and during totality.

Watch for the Moon's shadow sweeping across the sky before and after totality. Recording this with a wide-angle lens on a video camera gives very dramatic results.

Look for prominences -- especially any detached from the solar limb. Are they visible to the unaided eye or do you need to use binoculars.

Duration of the diamond ring ... does it linger a bit as sunlight floods through a valley on the Moon's limb. How long do Bailey's Beads persist.

Can you see the corona before or after totality. By blocking the Sun with a couple of fingers of my outstretched hand I was able to see the corona for a few minutes after totality at the 2001 eclipse while everyone around celebrated the end of the event. Don't consider the end of totality to be the end of the eclipse -- all the preceeding phenomena are played out in reverse.

Definitely bring a dictaphone and pre-record what to look for during totality. It will prompt you not to forget certain phenomena that are worth noting. Also, you can add a countdown to the end of totality on the recording.

Shadow bands can be picked up easily on video if planned for properly. Usually you can swipe the white sheets out of the hotel and lay them on the ground with a video camera pointing down to pick up these sometimes elusive phenomena.

Well, that's all I can think of at the moment!

John

I said nothing about relativity in the 1800's! I think the experiment I am on about was to do with sandclocks leaving at the same point of origin, to two different locations on the globe for a solar eclipse, and after recording their observations, the results were to help determine the Sun-Earth distance.

Seanie.

P.S. Somewhat related to what I am blabering on about, I did find this:

In 1672, Giovanni Cassini made a much better estimate by using Mars. By observing Mars from Paris and having a colleague, Jean Richer, also observe Mars at the same time in French Guiana in South America, Cassini determined the parallax of Mars. From that Cassini was able to calculate the distance from Earth to Mars, and then the distance from Earth to the Sun. Cassini calculated the AU to be at 140 million kilometers (87 million miles), which is lower, but very close to the modern day number.