Hi,
  Thanks for downloading, copying to 
otherwise obtaining my humble effort at 
Psion programming.

It's called Geoclock, I hope the name is 
not a trademark, but it basically is a 
little program to display a map of the 
Earth showing which part is in sunlight 
and which is dark. It will show you the 
current situation as well as any other 
day and time you care to enter. Due to 
the fact the Psion has now high speed 
number processor it is not the fastest 
of programs. However, having said that, 
once you've waited for the initial 
setups and calculations it will run in 
real-time, that means you can keep it 
running in the background to see what 
the current situation is at any time. At 
the bottom of the Earth map are three 
lines of cities and local times. You can 
change these times with one of the menu 
options.

The sun’s position is calculated to 
within a few arc-seconds, basically the 
amount the sun moves across the sky in 1 
second. The resolution of the Psion 
means that one pixel on the Psion screen 
is one degree on the Earth’s surface. 
The Earth spins round at 15 degrees per 
hour so give or take a pixel means give 
or take 4 minutes. Add to that the fact 
that the sun’s light is refracted or 
“bent” as it gets close to horizon plus 
the calculated position is the center 
and not the rim of the sun and this all 
adds up to almost another degree or so. 
I can easily correct for all this but to 
be able to do this for the 360 positions 
around the Earth would take a good 10 
minutes to calculate on the Psion. I 
might do a Java version if I get more 
time.

INSTALLING:
Just unzip the geoclock.zip file and put 
Geoclock.opa into the \APP directory and 
Worldmap.PIC into a new directory 
\APP\GEOCLOCK, you will have to create 
this directory using the Psion’s “make 
directory” (Psion +). Finally you will 
have to add the application onto the 
system menu with the “Install App” 
option (Psion I).

This version will expire at the end of 
the year, that is purely because I 
intend to update it well before that. In 
a future version you should be able to 
save the setup, including the cities 
you’ve setup. It should also show the 
position of the sun and moon with the 
moon’s phase. There are a few other 
ideas that people have kindly sent me. I 
am not a Psion programmer, it was 
several litres of Spanish sangria (a 
wine based punch) that got me into 
writing this program on a long weekend 
in Madrid. I don’t live on the poverty 
line but I will make the next version 
shareware with a $10 registration fee. 
This is basically to pay for the Sangria 
to which I am now sadly addicted.   :-)

Please give me any comments you have via 
email, 100116.574@Compuserve.com. You 
will always find the latest version of 
this program on my web page 
http://www.compulink.co.uk/~bonzo/Psion/

Thanks for trying it.

-John Davies-