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

In this Doc.
1.	ABOUT
2.	WHAT'S NEW IN 1.5?
3.	THE CALCULATIONS
4.	INSTALLING
5.	WHAT'S TO COME?

ABOUT:
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 no 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 cities with one of the menu 
options.

WHAT'S NEW IN 1.5?
This version as with the last one will
expire at the end of the year. It's just
a way to make sure every one has the most
up to date copy. I hope to have a new
version 1.6 (see what's to come) well
before that date. There are three main
changes with version 1.5 vis-a-vis 1.4.
The first is the ability to save the cities
along with one or two options, these are
saved into a database file geoclock.odb
found in \OPD. You can view and edit it 
if you like but if the program dies after
your mod please erase it to start again
from scratch. Secondly you can now display
the cities on the right of the map. They
are listed in time zone order starting
with -12 hours from GMT. This is the case
regardless of which line you put them in
when setting them up. The larger clock is
displayed under the map in this mode. You
can change between the two modes with the
diamond key, it's also saved when you exit.
Lastly I've added a "globe" view, you can
see the Earth as it would appear from
space. You can see either one or three
of these globes (see globes setup in the
menu). To see the globes wait until the
map is drawn before pressing the Psion-3
key. For the moment it is just a snap-shot
and is not live, that will be V1.6.

THE CALCULATIONS:
The suns position is calculated to 
within a few arc-seconds, basically the 
amount the sun moves across the sky in a 
second or two. This is getting less
accurate as time goes on. In the next
version (1.6 or 1.7) I hope to get 1997's
data, this will put the accuracy back to
within a second. The resolution of the Psion 
means that one pixel on the Psion screen 
is one degree on the Earths 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 suns 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've
started a Java version which I will soon
put on my web site. It's so fast on my
machine (Pentium pro 200MHz) that it
calculates several maps per second and
the globe view can be rotated in real-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 on any drive. You will have
to create this directory using the Psions
make directory (Psion +). Finally you will 
have to add the application onto the 
system menu with the Install App 
option (Psion I).

WHAT'S TO COME?:
I hope to get the latest 1997 figures to
allow me to calculate the sun and moon.
Following that I will show the moon and
it's phase. I think this may be in a later
version 1.7 rather than the next one. 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. The most resent mods were done
during the monsoon in Thailand, Thai Whiskey
and Singha beer helped a lot with the
sherical trig needed for the globe view.
I dont live on the poverty line but you
will see that this version adds the
"contribute" option. The address to send
the money to is my mothers'. She cooks me
great meals when I visit her in England so
the money will help to pay for a good party
at Christmas.

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-
