Astronomy Online

Software for Solar Eclipse (3-D)

This area contains software which is needed in connection with the 3-dimensional method for observations of the solar eclipse on October 12, 1996, as desribed on the Astronomy On-Line pages. Read that document first, before you attempt to use the software!

This software is used for the calculation of the value of the parameter D, explained in the above document.

Here are the instructions about how to use this software.

First, you click on each of the three links below. They contain files with the PC-compatible software which you need for this. In each case, you should store the corresponding file in your own computer under the name indicated here. How you store the files, will depend on your WWW browser. For instance, with Netscape, you should click on `File' (upper left corner of your window) and use the `Save File' facility. Once it has been stored, you may wish to move it to another, suitable directory.

The programme (latlong.exe)

Graphics software (egavga.bgi)

The picture (longlat.pcx)

Then you run the latlong.exe programme on your computer. It puts on your screen an image of the Earth, as seen from the Sun. This is how it looks like:

Now you enter the geographical coordinates of the two sites from where observations are made. You do so by moving the cursor to the corresponding fields in the upper right corner. When you click to the left of the number field, you increase or decrease the degrees; when you click to the right, the minutes change.

Sites which are East of Greenwich (most of the European continent) have negative longitude; sites West of Greenwich have positive longitude. Sites which are North of the Equator have positive latitude; sites South of the Equator have negative latitude.

Then you insert the time in the field below. Remember to use Universal Time (UT).

You will see that the picture changes, as you change the numbers. The geographical positions of the two sites are indicated by two spots, and the 0 longitude circle moves when the time is changed.

You can then read the value of D in kms from the corresponding field. This is the value you must use in your calculation.

You quit the programme by pushing FIN with the cursor. (FIN means "end" in French).

This programme was prepared by Francis Berthomieu.

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