THE CASIO
Graphing Calculator
fx-9860G Slim
This calculator can do many things, and while a normal price is around
$100, it can be found for less on some sites such as Amazon.

It can be programmed, and it has a spreadsheet. While it can link to a PC, it
will not work with Windows Vista 64 bit, which is what I happen to have. The
graphing function is cumbersome and cannot accept simple formulae such
as the 2 wave EOT, however the spreadsheet does them with ease.

Here are
some notes, and here are spreadsheets for the Almanac (EOT,
declination, sunrise and set), the HD and VD sundial types.

The .XLS spreadsheet can be opened and used in Open Office (.ODS)

The notes have some ideas on how the Casio spreadsheet differs from
Excel and Open Office, these notes can be very helpful.
PERSONAL PREFERENCE

In spite of the
HP35s hype ,
my personal preference is
the Casio fx9860, in
particular, the spreadsheet,
and its cost.