Eclipse '99 for the Psion Series 5

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Eclipse '99 was a program I wrote for my Psion Series 5 computer so that I could predict the start and end of the total solar eclipse of 11 August 1999 from wherever I happened to be. As it happens, I was at Shabla beach, in north-eastern Bulgaria, and I had a magnificent view of the most beautiful natural phenomenon I have ever seen. I am in the process of updating this software for the 2001 June 21 eclipse so that it gives more information and is generally better and easier to use. Enough of the graphics and display work has been completed to enable me to bring you this preview. In the mean time, this is a web page I put up in August '99 describing my work :-

This program gives the time of all 4 contacts, and mid eclipse, of the 1999 Aug 11 eclipse for your location, and it also gives a count down/up clock for those events and a countdown clock for the next event. This program, which I had hoped would be much more developed by now, is quite technical. If you do not understand what the program is doing, then it is probably not for you - there will be plenty of astronomers on the ground on 11 August to help you. I have decided to release this program in it's current unfinished state because if I didn't, the eclipse would probably be over before I would have a chance to finish it. I have got one more week-end to work on this program - there may be another version released on this web page on Tuesday 3rd or Wednesday 4th August.

Because this program is not yet fully developed, I am releasing it as freeware. You can use the registration name "Alpha Release User", and the Registration code "2C3A0D1C", to register it - note that the registration name is case sensitive.

A screendump :-

Some of the features of this program :-

Can read your position from a GPS (only tested with Garmin GPS 12 so far)
You can configure it to make corrections for the lunar limb profile, the latest delta t, your time zone, etc.
"Beeps" at you with 10 min, 5 min, 2 min, 1 min, 30 sec, 15 sec, 10 sec, 5,4,3,2,1 sec to go to the next event.
The "beep" can be turned off!
Gives distance and approx direction to the nearest point on the centre line (if you are within the zone of totality), and the "nominal" duration of totality there

NB - some of the features that there is provision for in the program, but are not yet developed :-

Sun plot
Read the time from your GPS
Continuous update of your position from your GPS (it will read your position once, and then disconnect from the GPS)
The manual was written some time ago - quite a bit of development has been carried out since then...

I do not believe that there are too many bugs in the software - the results it gives appear to be quite accurate. I will certainly be using it on 11 August, but then I wrote it, and so I know about it's quirks and limitations. This is an alpha release - as I said, it is being released now, because either I release it now, or never, and I can hope that someone out there will find it useful.

Please let me know how you are getting on. It is freeware, but please don't let that stop you from sending me money if you find it useful :-)

I will endeavour to work on the program over next week-end, and fix it up a bit. Let me know what I should make a priority.

Extra

One of the files in the distribution is called "Correction Curves". It is a data file containing the correction to be added to the time of second and third contact, to account for the lunar limb profile. The data came from figure 20 of NASA RP1398 - that diagram was digitised, and processed to produce a reasonably accurate and smooth digital version. To use it, if you are within the zone of totality, click on "Settings", "Limb Corrections". Your Psion will give you the second and third contact contact angles. Look up the "Correction Curves" table, and interpolate, to get the contact correction times.

References

The Total Solar Eclipse of 1999 August 11 - the authoritative web site, by NASA astronomer Fred Espenak.

NASA RP1398 - The Total Solar Eclipse of 1999 August 11.

Installation

Download this zip file, and install the files contained therein in \System\Apps\Eclipse.

Last Updated: 9 Sep 2000