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 1.55?
Since the last version (1.5) there is not
much new. I released this one to get over
my silly idea of making each version expire.
The idea was to make sure everyone had the
same version but in the end I just ended up
rushing to get something out before the
expiry date. I was a little stuck with
the last version for space to finish the
globe view. I have now changed the way the
various clocks work which has given me
quite a bit of extra room. This version
already has the space reserved for the
globes, I hope to add it for version
1.6 which should be ready by the end of
January. I hope you're pleased with this
version, it seemed fairly solid during
testing.

THE CALCULATIONS:
The sun’s 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, If you've seen a Astronomical data
book for 1997 please please let me know, I
tried to get one in London last week but
couldn't find one. 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 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'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 Psion’s
“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 have recently obtained a very much more
detailed map of the Earth, actually 144
times more detailed than the one I currently
use. I hope very soon to add a Europe and
USA option that shows the two areas in much
more detail. I may finish this before the
globes but we'll both have to wait until
V1.6 to see.
I hope to get the latest 1997 figures to
allow me to calculate both 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 don’t live on the poverty line but you
will see that this version has 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
next time I visit.

Please give me any comments you have via 
email, John Davies@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-