Category : Science and Education
Archive   : SKY121P.ZIP
Filename : SKY.DOC

SKY VIEW VERSION 1.21p


* About the program:
This is SKY, a planetarium simulator I wrote in Turbo Pascal.
To run this program you need 512k memory and CGA, EGA, or VGA graphics.

* Using it:
The program is easy to use:
First, with a text editor change the default observer locations
(in the file SKY.DEF) to where you are. Set the time zone to
-5 for EST, -6 for CST, -7 for MST, or -8 for PST. Note that
if you would like to have your times adjusted for daylight savings
time add an additional hour to your zone adjustment (-5+1=-4 for EDT).

********************************************************************************

After running sky a menu will be displayed on the left of your
screen, from it select the options you desire, then press "P" to
see the map.

NOTE: After the first map is displayed, you may use your
mouse to select a new center for the map (right button) or
to find out what's under the pointer (left button).

LETTER | - ACTION ------------------------------------------
===== | ===================================================
"D" + | changes date of observation
"T" + | changes time of observation
"O" + | changes observers earthly location

"A" | toggles display of constellation (and sun/
| moon/planets) abbreveations
"L" | toggles constellation line display on/off
"N" | toggles display of extra-stellar objects (NGC)
"G" ++| toggles display of celestial coordinate grid work

"M" | sets limiting magnitude (brightness) for map
"S" | sets scale (magnification) of map

"CZ" | sets center of map to zenith
"CE" | sets center of map to equitorial coordinates (RA/DEC)
"COS" | sets center of map by a star name
"COC" | sets center of map by a constellation abv.
"COP" | sets center of map to sun, moon, or a planet
"CON" | sets center of map by a NGC object
"COM" | sets center of map by a Messier object

"K" | provides a key to map: shows what NGC symbols are
| and what direction is north

"P" | plots map
"Q" | quits sky
===== | ===================================================

+ : these options cause a time consuming re-plot.
++: at magnifications above 30X this option is time consuming.

********************************************************************************

* Accuracy:
Star position calculations include precession (when
the year > 50 years from 2000.0).
Planets / Moon / Sun -
Plotted with routines from:
PRACTICAL ASTRONOMY WITH YOUR CALCULATOR.
GENERAL ACCURACY (don't count on this if your plotting
for 500BC or something! )
Planets - within .25 deg. of dec. & 3 minutes R.A.
Moon - within .20 deg. of ecliptic coordinates
Sun - within .05 deg. of dec. & 10 seconds of R.A.

* Speed:
On machines without an 8087 plotting will take a long time...
20 minutes on a 4.77MHZ 8088.
My 8086/8087 running at 8MHZ does a plot in about twenty seconds.


* Data-Base built from:
--------------- ------------
Yale Catalog STARS .DAT
Darrell Green's NGC200 .CAT
LINES .DAT by "me" (all ten blurry eyed hours of it!)
STARNAME.DAT by "me" (an hour or two)

As this is the first version (1.0p) for PC's (and a complete rewrite
of the last version), and for that matter my first real programming
project on an IBM-PC: things may not work properly...

Version 1.1p - corrects an error in the constellation line data-base
and adds support for the major color graphics standards. I've
also made a few changes to make the program more easy to use.

--> Version 1.2p - In this version I've made some major improvments:
First, as pointed out by Jim Lill (a CP/M RT sysop) I've added the
"0" in the ten's of minutes field (along with some other neating up).
After looking at Septembers issue of ASTRONOMY I decided to take
a look at the Moon's occulation of Tau-Scorpii from SKY... Very poor
accuracy on my part so... I corrected a bug in the sun/moon calculations
and added more calculations in the sun/moon/planet sections for better
accuracy (geocentric parallax corrections).
Then I improved on the "object lookup feature":
I added the names of the brightest stars (218 of 'em): they're displayed
with other star info when you press the left button of the mouse.
Also, I fixed the "C"enter option-it now works-and also added a search
feature to this option. This last feature makes the program useful even
if you don't have a mouse.
AND... too many other fixes/mods to mention (mostly small ones).

--> Version 1.21p - just moved the .BGI drivers into SKY.EXE and did
away with that silly .PAK format. I've also estimated how much memory
this program will need:

DOS - 64K
Main program - 94K
Data for " - 46K
Stack for " - 16K
Heap: stars - 176K
ngcs - 29K
star names - 5K
---------------
total 430K (512K leaves space for drivers, etc.)


If you note any additional problems just drop me a line, I'll do my
best to correct them.
Mail address - GENIE: H.DUTTON