Chris O'Byrne - Psion

I had written 2 applications for this machine - GarRec and Eclipse.

GarRec - Garmin GPS 12 raw data logger

As a result of some excellent experiments conducted by Antonio Galan, I decided to write a short, simple, data logger for the Psion 5 / Garmin GPS 12 combination. Disclaimer - this software uses undocumented and unsupported features of your GPS 12, and is not guaranteed to cause your GPS 12 no damage. Use at your own risk. To install the software, download this file, unzip it's contents into \System\Apps\GarRec on your Psion, and read the included help file before starting!

Eclipse - Total Solar Eclipse calculator

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.

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 :-)

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.