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1992-01-19
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STELLA Version 3.0
(C)opyright 1992
Andrew Palmer
---------------------------------INTRODUCTION----------------------------------
This is version 3.00 of the STELLA astronomy program. The main purpose
of this program is to give you the positions of celestial objects for the date,
time,and location on Earth. For each of the planets and somewhat for the Sun
and Moon the following data are calculated:
RA and Declination in HH:MM:SS
Distance in AU,KM,MI,and Light Travel Time
Angular Size in Arc Seconds
Magnitude
Illumination (Phase) in %
Altitude and Azimuth in decimal degrees
Geocentric Longitude and Latitude in decimal degrees
Local Time of Transit
Local Rising and Setting Times
Rising and Setting Azimuths
Conjunctions
Alignments within 0.5 degrees
Data Specific to the Moon includes:
Parallax in DG:MM:SS
Moon Age in days and degrees
Size in DG:MM:SS
This data is represented in text mode in detail and in a quick table format
that can also be printed. In graphics modes the planetary data is used to
superimpose the planet images onto STELLA's databases. Four databases are
included which contain the Messier catalog,the stars to magnitude 6.0,and a
portion of the NGC containing 2300 or so objects. Each object and planet has
its own symbol for easier identification. Also in graphics modes
representations of Jupiter's moons,a 'downward view' of the solar system,the
aspects of Mercury, Venus,Mars,and the Moon,and information on any
object,star,or planet pointed to can be obtained.
The epoch used for the planetary,lunar,and,solar calculations is EPOCH
1983.0. The positions of stars and objects taken from the references are of
various epochs ranging from 1950.0 to 2000.0. Long term and chaotic effects
are NOT calculated.
The files that MUST and the files that should be included within this
archive and are needed to run STELLA are:
STELLA.EXE The program file which MUST be included.
STELLA.CFG This is the configuration file. It MUST be present
to run STELLA. If it is lost or damaged running STELLA
with the /W switch will create a new default to start
over with.
STELLA30.DOC This document file.
STARCAT.DAT This is a catalog of 300 bright stars. It MUST be present
to use any graphics modes in STELLA. Text based usage is
not affected by the presence of this file.
EXTSTAR.DAT
MESSCAT.DAT
NGCCAT.DAT Three more catalogs containing the Messier catalog,the NGC
catalog,and catalog of stars between magnitudes 3.0 and 6.0
These catalogs need not be present to run STELLA.
STARCGA.GRP
STAREGA.GRP The planet and object image files for graphics modes. If
these files are not present then objects and planets cannot
be shown.
CONBIN.DAT This file contains 88 constellation records which contains
position info and latinizations. It must be present to
obtain star name information and to allow you to change
sky positions by constellation.
CURRENT.DAT File of meteor shower records. This is used when you obtain
current happenings using <F7> in text mode. If it is not
present then no meteor shower info will be shown.
STAR.TSC Opening screen file. Read direct to video text memory.
*.FNT EGA/VGA text mode fonts. Any direct video buffer character
set consisting of 256 chars or PCMagazine FONTEDIT files.
Points=FF_SIZE/256.
All the files that STELLA attempts to open are searched for in the current
directory first and if not found then on the DOS path. This pertains also to
files specified as parameters on the command line.
If you don't specify then STELLA checks the hardware and determines which
text and video modes are best suited for use. Whenever a file that is not a
MUST file cannot be opened or memory for it cannot be allocated an error
message will be displayed before continuing. STELLA uses quite a bit of memory
in graphics modes so it is best to have as much free DOS ram as possible. If
you are using an EMS driver STELLA will allocate whatever it can (usually
around 64k) for its own use. Some tasks (such as background printing in
graphics) require large blocks of memory for themselves and will preclude other
tasks from operating (those that page swap for example).
This .DOC file provides an overview of the STELLA program. The best way to
learn it is to use it and I think I've kept it pretty simple. In this .DOC any
keystroke descriptions also pertain to mouse button presses. The mouse can be
used anywhere in STELLA except for input of numeric values (such as changing
the time and date).
I hope that you find STELLA useful and fun to use. I tried to make it as
straight forward and easy to manage as I can. I have left two functions
undefined: one in text mode and one in graphics which I want to take user
suggestions as to what their roles should be. I have played with some ideas and
have oodles of code for most but can't seem to decide which would be most
useful. Please feel free to contact me at the addresses listed under Registra-
tion or via Compuserve Mail [76106,572].
I hope you enjoy this program and I thank-you for your support.
Andy Palmer
--------------------------------REGISTRATION-----------------------------------
STELLA version 3.0 is a shareware program. It has been around since Z80
days (albeit in different form!) and has taken much time and effort (if you can
believe it!). If you would like to register for $30 dollars and receive free
updates,an illustrated manual,and your registered copy you can mail to:
Andrew Palmer
129 Amboy Ave.
Woodbridge,NJ 07095
The manual contained in the registered versions contain file format
information not included in this document file. Also included in registered
versions are the function prototypes that STELLA uses for display of maps in
graphics modes as well as illustrations explaining aspects of the program.
If you would like to contact me to make any suggestions or report any
(ugh!) bugs I can be reached via ILINK or Compuserv Mail [76106,572].
-------------------------------Starting STELLA---------------------------------
To run STELLA properly move all the files contained within the archive to
a single directory. STELLA will also look along along the DOS path for any
files it is trying to open. The command line for STELLA is:
STELLA [/hecd] [/Fname] [/Pname ] [/w] [/x] [/0..9]
Where:
/hecd= Force graphics video mode.
H=Hercules Mono 720x348 (2 page)
C=CGA 640x200 (1 page)
E=EGA/VGA 640x350 16 color (2 page)
D=Dual monitors. Text=Start up screen.
/Fname= Load user EGA text fonts. Loads the fonts specified by name
Text mode fonts ONLY apply to EGA/VGA systems.
/Pname= Printer file output if you would like to change the default
The default is STEL_ELM.TXT in the current directory or
on the DOS path.
/w = Create new default config file. To be used in case the
one provided gets lost or damaged.
/x = Do not use EMS memory.
/0..9 = The configuration to use. STELLA saves 10 configs numbered
0 thru 9 in the STELLA.CFG file. You can select any one on
start up.
All of the switches are optional,case doesn't matter,and the switch char
is optional (thus STELLA /x /w /FHal14.fnt is the same as STELLA -x w -FHal14.
fnt) . When STELLA starts it begins by parsing the command line. If no switches
are found then the program determines which hardware config is appropriate and
uses default values. The defaults and some explanations are as follows:
Video modes: STELLA determines which video modes to use for text and
graphics. If you are using dual monitors and you start STELLA
from the mono screen the default for graphics is either
CGA/EGA. If you want to use Hercules mono for graphics,use the
'H' option. If you start STELLA from the color screen with dual
monitors you MUST use the 'D' switch to force Hercules graphics
mode.
Font set: STEL_FNT.FNT is the default font if found. If it is not found
and is not specified using the 'F' switch then the system font
is used. Font files specified are searched for in the current
directory and on the DOS path. See Loading Fonts below.
EMS: 'X' prevents use of EMS memory for databases and graphics
buffers.
Configuration: Specifying a number will choose a different start up config.
The default is ALWAYS 0,which uses the system time and date.
If you ever need to create a new config file use the 'W' switch
to create one in the current directory. See Configurations
below.
Printer Output: When printing text output STELLA will always ask if you would
like to send to printer or file. The default file it sends to
is called STEL_ELM.TXT. If you would like to change this use
the 'P' switch (ie. -Ptoday.txt). The default directory is the
current one. A file specified using the 'P' switch is ALWAYS
searched for first in the current directory and on the path. If
it is found it is ALWAYS appended to;if it is not found it
is created. See <F8>-Text Printing below.
---------------------------------LOADING FONTS---------------------------------
The font that STELLA uses for EGA/VGA text is user selected. The default
font is whatever is contained in the file STEL_FNT.FNT. This file is shipped as
a 14 point 'Arabic' font. I've also included some others that are interesting.
You can rename any of the *.FNT files to STEL_FNT.FNT if you prefer or you
could create your own or you could pass the file name as a parameter on the
command line preceded by the 'F' switch:
STELLA /Fhal14.fnt ( Will load font HAL14.FNT from current dir
or path.)
Font files are searched for in the current directory and on the DOS path.
If the selected file is not found or is not a compatible font file then the
system font is used.
Font files are straight binary files containing 256 chars (0..255) of a
given number of points. The files MUST contain 256 chars;STELLA determines
POINTS=FILESIZE/256. The fonts are attribute selected low and are written to
page 1 of EGA character RAM so as not to trash page 0 which is used to enhance
the highlight bars.
I have also included support for fonts generated by PCMag's FONTEDIT.COM.
These fonts MUST have a size of 8291 bytes. Any font file of this size is
usable but special criteria must be met to insure they are true PCMag files.
STELLA will re-size windows to fit the start up EGA/VGA mode (ie 43 line,
28 line,etc.) so choose an appropriate font you like that also fits well. I
have included fonts of various sizes for experimentation.
------------------------------CONFIGURATIONS-----------------------------------
STELLA allows you to SAVE/LOAD 10 different configurations. When STELLA
starts it looks for the file STELLA.CFG in the current directory and path. If
it is not found then STELLA exits with a fatal error. To create a new config if
one is ever needed run STELLA with the 'W' option. STELLA CANNOT run without
the config. If you use the 'W' switch, STELLA creates the new config and then
continues running.
The default config is configuration #0. Configuration #0 is special in
that the time and date are ALWAYS assumed to be system time and will not be
altered. The other data that is saved in the configurations are:
Value: Default:
Time and Date if not configuration #0. n/a
East/West status. WEST.
Latitude (+N/-S),Latitude. DG:MM:SS 42:00:00N,72:00:00
Daylight savings status. OFF
Printer Port,Passes. LPT1,1 Pass
Status of Catalogs On/Off. All ON.
Draw Ra,Declination,Ecliptic lines in graphics. NO.
Name plotting magnitude stars. 1.0-1.0 (No plotting).
Object plotting. All OFF.
NGC Object magnitude range to draw. 0.0-10.0
Text color and Standard color in graphics modes. YELLOW,LIGHTCYAN.
If you use the '#' option on the command line STELLA will use the chosen
config on start up:
STELLA 5 (Start STELLA with config 5)
The <F2> key in text and graphics modes will allow you to SAVE/LOAD
configs while inside STELLA.
-------------------------------Running STELLA---------------------------------
----------------------<<<<<The Text Window Screens>>>>>-----------------------
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓┌────────────────────────────────┐╔════════════╗
▓ Current time ▓│ Options: │║ Ready: ║
▓ setting: ▓│ │║ ║
▓Year: 1991 ▓│ Daylight Savings: NO │║ Mercury ║
▓Month: December ▓│ Latitude= 42:00:00 │║ Venus ║
▓Day: 11 ▓│ Longitude= 72:00:00 │║ Mars ║
▓Julian: 2,448,601.71 ▓│ E/W Longitude= West │║ Jupiter ║
▓ ▓│ Messier Catalog: Off │║ Saturn ║
▓Local: Local Time ▓│ Extended Catalog: Off │║ Uranus ║
▓UT: Universal Time ▓│ NGC Catalog: Off │║ Neptune ║
▓LST: Local Sidereal ▓│ Printer Port: LPT1 │║ Pluto ║
▓UST: Universal Sidereal ▓│ │║ The Moon ║
▓ ▓│ │║ The Sun ║
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓└────────────────────────────────┘╚════════════╝
╔═════════════════════════════════════════════════════════════════════════════╗
║ ║
║ Done!! ║
╚═════════════════════════════════════════════════════════════════════════════╝
╔═════════════════════════════════════════════════════════════════════════════╗
║<F1>--Help! <F4>--Graphics displays <F7>--Happenings ║
║<F2>--Save\Load Config. <F5>--Quick information <F8>--Printout ║
║<F3>--Reset to system time <F6>--Recalculate <F10>-??? ║
╚═════════════════════════════════════════════════════════════════════════════╝
After the cover screen,the first screen will show five windows. The names
of the planets will begin to appear in the third window as they are calculated
based on the current config. Either the mouse or the cursor keys will move the
highlight and the bold box among the top three windows. The long window in the
center of the screen is used for messages. The <RIGHT> mouse button will
preform an <ENTER> and the <LEFT> button will perform <ESC>. When using the
mouse just move the text mode cursor to the item you desire to change and hit
the <RIGHT> button. Some of the values are toggles while others require a
specific range and format of input. Any character surrounded by '<>' brackets
can be used also. To abort a function (like printing or loading a config) use
<ESC>. <ESC> also exits STELLA.
Window 1: Current time setting
The year and day are input as numbers. Specify years with centuries (so
'1989' NOT '89' which will be read as 89 AD). Years before 1 AD are
input as negative numbers (ie. -4713) thus there is no year 0 (it
is -1). The month is a toggle which rotates the month.
Any of the times can be changed and the results are back calculated.
Input times as HH:MM:SS WITH the colons. If you put in 50:45 it will be
read as 00:50:45. A value of 0:5:0 will be interpreted as '00:05:00',so
zeros are only needed when used as place markers. A <SPACE> char zeros
out the time. The display is rewritten so if the time you input isn't
the time that appears then try again. Always put a zero for places not
used. Hitting <ENTER> without entering a value leaves it unchanged. The
meanings of the time abbreviations is given in the diagram above.
The Julian Date is updated whenever any time is changed. The Julian
Date CANNOT be changed.
After any changes the planetary coordinates aren't up to date anymore.
<F2> will recalculate them.
Window 2: Options Window
Daylight Savings-
This is a toggle: Yes/No. Either it's daylight savings time or standard
time. The times in the Time Window are updated if it's toggled.
Daylight Savings ONLY applies to the Local Time thus when it is on
Local Time is assumed +1hr.
Latitude & Longitude-
The lat. or long. you are interested in. For me it was 42:00:00 and
72:00:00 West and they are the defaults. You can input anything you
like. Input the same as for time: DG:MN:SC with the colons. Use
negative,'-', for Southern latitudes. Use zero for places not used
(ie. 42:00:05).
East/West longitude-
A toggle between West of Greenwich,England and East of it.
All times are then updated. The default is WEST
Extended,NGC,and Messier Toggles-
Will turn on/off the access of these three catalogs for graphics
displays. All catalogs are ALWAYS read once upon entry into graphics.
These toggles determine whether or not they are displayed. The default
is ALL ON.
Printer Port-
Will allow you to specify where the printer is on your computer.
This is toggle from LPT1 to LPT3,COM1 and COM2. The default is LPT1.
Window 3: The Planet Window.
This window contains a list of the planets,the Sun and the Moon. When
the highlight is on one and you hit <ENTER> or you click the mouse on
one you will get a display of:
Ra and Declination
Distance in AU,km,mi
Size in arc seconds
The light travel time
Illumination (phase)
Magnitude
Altitude (negative altitudes mean below the horizon)
Azimuth
Geocentric longitude
Geocentric latitude
Transit time
True and apparent rising and setting azimuths
True and apparent rising and setting times
The last time the planet was calculated for.
There are various other calculations,pertaining to the
Sun and Moon,that appear for them. Hit any key to return to the menus.
---------------------------<<<<<The <F> keys>>>>>-----------------------------
In the bottom window is a brief description of the <F> keys. I will
explain them more fully here.
<F1> This will bring up a small help screen with some tips on how
to move around and change things.
<F2> Save/Load Config. Will allow you to load or save new configs
while in STELLA. Either move the highlight and hit <ENTER> or just
hit the number to choose a config. The information saved is explained
above.
<F3> This key will reset the time to the current system time. STELLA
assumes the system time is correct locally and loading Configuration 0
(Default) always sets this on start up. STELLA does not ever set the
system clock so the time variables can be updated anytime in text or
graphics.
<F4> Switch to graphics screens. See the next section on graphics
for details. Suffice to say that if the highlight is in the Time or
Options Windows you are placed on a mercator projection if the entire
sky. If the highlight was on a planet then the screen is zoomed
to that area.
<F5> This key will show:
R.A. and Declination
Distance in AU
Angular Size
Light travel time
Phase
Magnitude
Altitude and Azimuth.
Data is shown for all the planets,Sun,and Moon in table form on one
screen. This is the same format as used for text mode printing.
<F6> Recalculate the planets,Sun,and Moon for the shown time. If the
highlight bar is in the Time or Options Window ALL the planets are
recalculated. If the highlight rests on a planet ONLY THAT PLANET will
be updated. The time used is the setting in the current Time Window.
When you go to a planet's screen the time the last calculation was made
is shown on the bottom.
<F7> Get Current Happenings. Information is calculated and shown
for the following:
Oppositions and conjunctions of planets.
Alignments within 5.0 degrees for the planets,inludes the Moon.
The Moon's phase.
Info on current meteor showers.
The time and date currently shown in the Time Window is used as the
basis of the calculations. Oppositions and Superior Conjunctions are
flagged within 1.0 degree. Conjunctions and Inferior conjunctions are
flagged within 1.25 degrees. Alignments between the planets or a planet
and the Moon are flagged within 5.0 degrees and the degree span is
shown. Meteor showers are shown with dates,radian,and average rate. If
the file CURRENT.DAT is not found then information on meteor showers is
not shown. Hitting a key after the beep to scroll through the
happenings.
<F8> Will printout the properties of each planet,the Sun and Moon.
When you are asked to hit a key and you hit <ESC> the printing is
aborted. The data is the same as appears when hitting <F5> for quick
information.
STELLA always asks if you would like to sent the file to the
printer or a file. If no name was specified with the '/Pname' option on
the command line STELLA looks for the STEL_ELM.TXT in the current
directory and on the DOS path. If STELLA finds existing files they are
ALWAYS appended,else they are created in the current directory if not
specified.
<F10> I don't know. Maybe you do?
<ESC> Will leave the program.
----------------------<<<<<The Graphics Screens>>>>>-------------------------
To use the graphics you must have either a CGA,Hercules,EGA,or VGA system.
If you don't,the calculations will run fine but you will not be able to enter
graphics,obviously. In CGA there is no color since I used Hires mode. In
EGA or VGA the star colors appear by spectral type.
If the file STARCAT.DAT is not found then you also cannot enter graphics
modes. If the file STARCGA.GRP (or STAREGA.GRP) is not found then planets and
objects will not appear.
When STELLA first enters graphics it begins to read its data files. Any
errors are shown on screen and STELLA waits for a key stroke. Some errors that
will not allow the use of graphics are:
CANNOT find STARCAT.DAT.
EGA/VGA 640x350 16 color mode requires two pages to be able to
run for STELLA. This requires a memory of 256K available to the
graphics system.
Hercules mono means TRUE Hercules Mono,NOT EGA/VGA mono modes. Two
pages are also used requiring 32K graphics system.
CGA requires a 16K RAM allocable buffer which can be placed in
XMS memory if available.
If you are using a mouse then the primary pointing device is the mouse
graphics cursor. If you do not have a mouse then the pointing device is a small
cross that is moved via the cursor keys. Again the <RIGHT> button preforms an
<ENTER>|<Y>es and the <LEFT> button an <ESC>|<N>o. <ESC> will close windows
without function execution and also exit graphics mode. Graphics can be
reentered any time from text by again using <F4>. STELLA does not reread its
data from disk and will send its graphics data to XMS memory if available.
Depending on which window you were in when you hit <F4> you will get one of
two views. If you where in the Time or Options Windows then you will get a full
mercator projection of stars to magnitude 3.5 with the planets inserted. The
R.A. given on the bottom of the screen will be the 12hr RA-0.0 deg declination,
You can move the pointing device anywhere on this map and hit <ENTER> and the
map will zoom to that location. If the device has did not move before hitting
<ENTER> then the screen in centered on the LST and the celestial equator.
Hitting <ENTER> on the mercator projection will zoom to the location you were
pointing to.
If you where in the Planet Window then you will be roughly centered on the
planet you where pointing to. The area spans a 5hr by 45 deg. square of sky.
The R.A. and Dec. are those of the planet. The magnification always begins as
1x and increasing this divides the default by the magnification factor. Moving
the pointing device will change the R.A. and Dec. on the bottom of the screen.
<ENTER> on a zoomed screen will search the catalogs for information on objects
located at that position. If an object is found a small 'X' will appear at the
objects location. Object hits occur within 0.5 degrees of Declination and 0.25
degrees of R.A.. Hitting <ENTER> continues the search;<ESC> moves on to the
next catalog to search. The catalogs are searched in the following order:
1. Messier Catalog.
2. NGC
3. STARCAT.DAT
4. Extended star catalog.
Only catalogs specified as ON will be searched. All magnitudes and types
are scanned irregardless of active filters.
On the mercator projection only stars,the planets,the Sun,and Moon are
shown. The Moon's aspect is calculated and it is drawn in the correct phase.
When the screen is zoomed ALL objects are shown.
When you are on a zoomed screen you can scroll in R.A. and Dec. by use
of four key combinations or by clicking on the small arrows at the bottom of
the screen.
<Ctrl><PgUp> or Up Arrow: Scroll screen/sky up and move to lower declination.
<Ctrl><PgDn> or Dn Arrow: Scroll screen/sky down and move to higher
declination.
Moving in declination copies one half the screen to the other depending on
direction and then updates the remaining portion. Remember that PgUp/Up Arrow
means scroll the SCREEN/SKY up,therefore moving to decreasing declination
centered on the screen.
<Ctrl><Left Arrow> and <Ctrl><Right Arrow> move to greater R.A. and lower
R.A.,respectively. The amount of the scroll depends upon screen mode and the
current level of magnification.
If the STELLA cannot allocate memory for a window the program will display
the window's contents anyway. If you are not doing something that then requires
the screen to be redrawn the sky map will be messed up! Use the <ALT><R> key
combination to force STELLA to redraw the screen at anytime.
<<<<<<<<<<<<<<<<<<<<<<< Graphics Menus >>>>>>>>>>>>>>>>>>>>>>>>>>>>
On the bottom of the screen it says '<Menu 1>' and '<Menu 2>'. You can use
the mouse to click on either of these or use <F10> for Menu 1 and <Alt><F10>
for Menu 2. ALL <Menu 2> items use <Alt><Fkey> combinations. Each function can
be called by hitting the key listed next to it,moving the highlight bar to it
and hitting <ENTER>,or pointing the mouse at it and clicking. Some will pop up
a second and third window with specific options. All the windows work the same:
<ENTER> will choose an option and <ESC> will close any window and abort the
function.
<F1>-Goto...
'Goto' allows you to quickly move to another area of the sky. The current
magnification is used to redraw any screens. Another window appears which
contains these options:
RA and DEC Specify a RA and DEC to go to. Specify any R.A. and Dec.
and you will zoom to it.
Planet Choose a planet to go to.
Constellation Choose to go to a constellation. It is only roughly
centered on the constellation. The list contains all 88
constellations.
LST: Center on the local sidereal time and the celestial equator.
Object Choose an object by name.
RA and DEC: The values are input the same as in text mode for entering Time
values. Use zeros for places not used. Southern Declinations must
be preceded by a '-'. STELLA will show how it interpreted the
input and ask if it is correct before proceeding. Invalid values
are scaled to fit (ie. 25:0:0 will be 23:00:00 and 180:0:0 will be
90:00:00).
Planets: Another menu will open and allow you to choose from a list of
eight planets,the Sun,and Moon.
Constellation:
If the file CONBIN.DAT was not found by STELLA this function will
be unavailable. Either move the asterisk around with the arrow keys
or double-click with the mouse on the constellation name. Hitting
<F10> will show the full Latin name of the constellation next to
the asterisk. The abbreviations in the list are sorted by full
Latin names so Canes Venatici,which is abbreviated CVn,comes
before Cassiopeia,abbreviated Cas.
LST: This will center the screen on the Local Sidereal Time and the
celestial equator.
Object: This option allows you to enter the names of objects and have
STELLA search its' databases for a match.
The rules that apply to moving to areas by name are:
Star names are not included in any searches.
Upper and lower case letters make no difference.
Portions of names are allowed,such as 'Somb' for the Sombrero
Galaxy and 'Ori' for the Orion Nebula. The first match STELLA
finds is assumed to be correct.
If it is a proper name (i.e. 'ring' or 'Andr') it is a Messier
Object.
If it begins with 'M' (i.e. 'm57' or 'M 42') it is also a Messier
object.
If it begins with 'N' or 'ngc' then it is an NGC object.
<F2>-Save/Load Configurations. This is the graphics equivalent to the
same text mode function.
<F3>-Reset to system time. This is equivalent to the text mode function
excepting that the planets are redrawn to their new locations and the
Moon's phase is updated.
<F4>-Input Time. A small menu will allow you to input new times and
dates for graphics displays. Only the Local Time can be specified
along with the year,month,and day. ALL the planets are ALWAYS
recalculated using this function. The same rules that apply to
entering times/dates in text mode apply here. The mouse is not used
for this window;the arrows will move the highlight up and down;<ENTER>
will allow you to change the data. <ESC> will close the window and
ALWAYS recalculate positional elements.
<F5>-Zoom/Full Map. Depending on where you are <F5> will take you to the
other view. If you are on the mercator projection you will zoom to the
last zoom-window you were at. If you haven't zoomed on anything yet
then it will go to your current LST and the celestial equator. If you
are in zoom-windows you will go back to the mercator projection. The
menu will always show which direction the toggle is facing.
<F6>-Toggle Lines. This is used to turn off R.A. and Declination lines,and
the projection of the ecliptic. R.A. lines are placed on whole hour
marks (ie. 06:00:00hr,22:00:00hr) and Declination Lines are drawn
every 10 degrees. If you are using EGA/VGA the R.A. and Dec. lines are
shown in magenta,the celestial equator in yellow,and the ecliptic in
green. For all modes the aspect of the lines vary for identification.
The status of the line drawing is saved in the configuration.
<F7>-Toggle Planets. Will turn on and off the showing of planet,Sun,and
Moon images.
<F8>-Printout. This function allows the graphics printing of the current
screen and will need some explanation. Graphics printing is ONLY
available for Epson compatible printers. If you are using either
EGA/VGA or Hercules mono then printing can be done in the background.
The print routines use the second graphics page to hold data so some
STELLA functions will not be available. These functions are all
located on <Menu 2> and are explained beginning below. In the
notes I make mention of which do not work when background printing.
Printing cannot be aborted once it's initialized except by exiting
graphics mode. STELLA will ask if you really want to abort printing
before returning to text. Graphics printing requires around 11K of RAM
which can be located in XMS memory. Color printers are supported and
stars are printed according to spectral type.
The first print menu asks for some basic information:
Port: The same as the Configuration Port and text mode port.
Number of passes: How many passes of a scan line you would like
to have the printer make. This will print the same lime the given
number of times to make printouts darker. The default is 1; the max-
imum is 5. My only printer is an MX-80 and passing over the same
lines 2 or 3 times really made better images.
After these values are satisfactory hit <ENTER> on DONE to continue.
The next window will ask you if you want to add object or star names.
Hitting <Y>es or <N>o will allow you to place proper names next to
objects you choose. If you choose <Y>es then you can move the pointing
device anywhere and STELLA will search the catalogs. The searching
follows the same rules as normal searching but hitting <ENTER> when an
item is found causes its name to placed next to it. Hitting <ESC>
continues with the search. ONLY IN CGA mode will you see the name
appear on screen. In EGA/VGA and mono you must hit <P>review or click
on <P>review at the bottom of the screen. The only way to remove names
is to reclick on the object and NOT choose to keep it (hit <ESC>) when
it is found. After the screen is satisfactory hit <D>one or click on
<D>one at the bottom of the screen and printing will begin.
<F9>-Magnify. Screens can be magnified up to 5x. The default ALWAYS
starts at 1x. 1x is equal 5hrs of R.A. and 45 degrees of declination.
2x=1/2, 3x=1/3,etc. 5x shows 1hr of R.A. and 8 degrees of declination.
The mercator projection map CANNOT be magnified.
<<<<<<<<<<<<<<<<<<<<<<<<<<<<Menu 2>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
<Menu 2> is accessed by the <Alt><F10> key combination or clicking on the
word at the lower right of the screen. Individual functions are accessed by
picking them off the menu or using <Alt><Fkey> combinations.
<ALT><F1>-Jupiter's Moons
This will show you a view of the Moons of Jupiter for the current time and
date settings. If you printing in the background this function CANNOT be
used. <F10> or the <Right> mouse button will bring up a second menu;<Esc>
will exit back to the map screens.
The second menu controls the following functions. Either using their
<Fkeys> or clicking on them will access them.
<F1>--Move the Moons
This will move the moons for a given time interval. You choose
whether you will increment or decrement the scale,the scale in
years,days,hours,OR minutes,and the step of the interval. The step
is input as a decimal real number. ALL the moons are always moved.
At the bottom left of the screen the time is updated as movement
proceeds. Hitting <F3>,<ENTER>,or the <Right> mouse button will
pause the movement and display the moons names. <ESC> stops the
movement. Unfortunately you cannot tell if the moon is behind the
planet or in front.
An example might help clarify:
Say you want to move forward in time by 10 minute intervals.
Call up the Movement Menu,select increment,select MINUTES from scale
menu,and input '10' for the step.
<F2>--Reset to System Time
Will redraw the moons using the system time.
<F3>--Names
Will show the names above the moons. This will not stop the
movement which continues after another key is pressed.
<F4>--Input date/time
This allows you to enter any time to use for drawing the moons.
This doesn't effect the time used for any other calculations or
maps. The input is exactly the same as for <F4> globally.
<ALT><F2>--Phases
This shows close-ups of the Moon,Mercury,Venus,and Mars and displays their
phases for the current time settings. If you are background printing this
function CANNOT be used.
<ALT><F3>--Angle between objects
When you choose this function STELLA will take the next to locations that
you click on and calculate the angle between them. You move the pointer
device to a location on the screen and hit <ENTER>,choose another location,
hit <ENTER> and the angle between the objects will be displayed.
<ALT><F4>--Miscellaneous
The Miscellaneous screen shows the same output as <F5> Quick Display does
in text. You CANNOT use this function while background printing.
Also from this screen you may change the colors used for menus and graphics
text output. Standard Color is the color STELLA uses for the rectangular
border,the two main menus,and the RA and Declination on the bottom of the
screen. Standard Text is the color of text in all submenus and data
produced from searching catalogs.
To change a color use the right/left arrow keys to move between the menus
and the up/down keys to move the rectangle,or just point and click with the
mouse. <ESC> will close the two windows and place you back on the data
screen.
<ALT><F5>--Downward View
This will give you an elliptical view of the Solar System looking down. You
CANNOT use this function while background printing. The view is calculated
for the current time settings. <F10> or the <Right> mouse button
ill bring up a second menu which will allow you to specify:
<F1>-Movement
You can increment or decrement time and see the results by selecting
<F1>. A menu will appear asking which planets you would like to move.
Specifying ALL will move all of them. Either click on them or move
the highlight and hit <ENTER> to change their status from 'FORGET' to
'MOVE'. After you have specified which you would like to move hit
<ESC> or click on 'DONE'.
You will then be asked to Increment/Decrement (forwards/backwards) in
time. Then the scale menu asks for Years,Days,or Hours. The step of
the scale is input as a decimal real number. The calculations then
proceed and the chosen planets are moved. The date/time in the lower
left is adjusted accordingly. <F3>|<ENTER> or the <Right> mouse
button will pause the movement and display the planets names above
them. <ESC> stops the movement.
<F2>--Reset to system time
Will redraw the planets using the system time.
<F3>--Names
Will place the names of the planets next to each in case you can't
tell. This does not stop movement.
<F4>--Input Date/Time
Redraw the screen using a new time and date. This is identical
to <F4> on the maps. Use zeros for places not used. This does not
effect any other calculations or maps.
<F5>--Change View
Redraw the ellipses using orbital data or standard. If you are
viewing using standard size ellipses then you will get a view of
either the inner or outer planets depending on which you specify.
The ellipses are drawn from orbital data and display the correct
elliptical design of the orbit. All the <F> keys work here with the
<F5> key taking you back to standard ellipse views. For the basic
algorithm for the orbital ellipses I am endebted to Larry Puhl, the
author of PLANETS.COM. With few modifications I was able to use his
technique in STELLA.
<ALT><F6>--Limiting Ranges
This function allows you to filter what STELLA shows on the screen and to
scroll through the plotting of stars and objects. The object list includes
Open and Globular clusters,Galaxies,Planetary Nebula,Diffuse Nebula,and
Cluster Nebulas. The object type 'UNKNOWN' is still listed but I went
through the catalogs and updated any 'UNKNOWN' object to the correct type.
The menu shows three selections: STARS,OBJECTS,and the NGC:
STARS: This function allows you to specify a magnitude range for which
any star that falls between it,the name will appear next to it
and plotting of stars will not continue until a key is pressed
or mouse button hit. Names are shown with three letter Greek
designations and three letter constellation names when
applicable. If the star has an Arabic proper name it is used
instead (ie. Aldebaran for Alpha Tauri). Hitting <ESC> during a
pause will abort the pausing and finish drawing the screen. The
range is specified by increasing or decreasing the brightest and
dimmest magnitudes. When both are set equal no pausing will
occur. If you put the magnitudes in a reverse order (dimmer
magnitude less than brighter) STELLA will reverse them. The
brightest magnitude is -3.0 and the dimmest is 17th. Any changes
will be saved to the configuration file. The default is 1st
magnitude for both values which disable the function. These
values are saved in the configuration. Use the right/left arrow
keys to increase/decrease the values or click on the arrows
with the mouse.
OBJECTS: By selecting various objects objects as 'ON' you will allow
the name of that type of object to shown next to it as it's
drawn. Messier object names take precedence over NGC names.
Plotting continues after each keystroke;<ESC> will abort showing
the names and finish drawing the screen.
NGC: The NGC function here works the same as that for the STARS,but
it does NOT control the pausing,ONLY the range in which objects
will be plotted and therefore acts as a filter. The default
range is of 1st to 10th magnitude objects. For the plotting of
NGC catalog names see Catalogs below. These values are also
saved in the configuration file.
<ALT><F7>--Catalogs
The catalog function allows catalogs to be disabled or enabled and also
provides the pausing for the NGC catalog if it's being accessed. The 'NGC
STEP' item when turned 'ON' will place the names next to all NGC catalog
items STELLA plots. Plotting pauses until a key stroke. <ESC> will abort
the pausing and finish drawing the screen. The status of the catalogs and
the NGC step are saved in the Configuration file.
<ALT><F8>--Legend
This will show you the symbol window. This tells what each symbol on the
screen represents. The Moon symbol is generic and is not the same as that
which is drawn on the maps. The Moon on the maps is always in the correct
phase. If you hit <ESC> then the function ends. Any other key will show you
the star colors and magnitudes. The colors obviously have no meaning in
CGA and Hercules where all stars are plotted white.
<ALT><F9>--??
I don't know?
----------------------------APPENDICES and NOTES-------------------------------
Appendix A: References
I used many references to form the equations used in the program. The
main ones include:
Adventures in Celestial Mechanics Victor G. Szebehely
Astronomical Methods and Calculations Agnes Acker and Carlos Jaschek
Practical Astronomy with your Calculator Peter Duffet Smith
Algebra and Trigonometry Mustafa A. Munem and David J.
Foulis
The star catalogs came from:
Burnham's Celestial Handbook Robert Burnham Jr.
Amateur Astronomers Handbook James Muirden
The Webb Society Handbooks Vol 1..6 The Webb Society
Peterson Field Guide to the Stars Donald H. Menzel and
Jay M. Pasachoff
PCMagazine is a trademark of ZIFF Communications.
FONTEDIT.COM is (C)opyright 1989 by Michael J. Meddford for PCMagazine.
STELLA was written using Borland's Turbo Pascal 5.5.
Appendix B: File Formats
STELLA opens quite a few files when it is running. Some of these are files
that can be changed by the user. The manual for the registered version of
STELLA gives the structures of the files and the important procedures and
functions that use them.
Appendix C: Comparisons
The accuracy of the R.A. and Declination varies for a number of reasons.
The greatest error I've been able to check only amounts to minutes of arc in
R.A. and minutes in Declination. Usually the program is accurate to a few
seconds in both axis. Below is a comparison of the output of STELLA to
that in Astronomy and/or Sky and Telescope:
STELLA
1/15/1990
18:38:37 LT 23:26:38 UT
2:22:16 LST 7:10:16 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mar 17:15:59 -24:08:09 2.22 4.21 0.31 96.43 1.71 282.54 -50.01
Jup 6:13:56 +23:19:16 4.24 46.44 0.59 99.87 -2.50 92.37 38.86
Sat 19:14:44 -22:03:07 11.04 15.00 1.53 100.00 1.33 263.64 -26.83
Ura 18:31:28 -23:31:35 20.32 3.24 2.82 99.99 5.83 269.19 -35.72
Nep 18:51:26 -22:03:02 31.23 1.99 4.33 100.00 7.77 267.35 -31.14
Plu 15:16:35 - 2:13:56 30.03 0.27 4.16 99.94 14.00 339.31 -48.41
1/15/1990 0.0hr UT Epoch 2000.0
Mar 17:15.1 -23:14 2.228 4.2 96% 1.5
Jup 16:15.5 23:19 4.226 46.6 100% -2.7
Sat 19:15.3 -22:02 11.001 15.0 100% 0.5
Ura 18:29.4 -23:33 20.316 3.4 100% 5.8
Nep 18:54.8 -22:00 31.171 2.1 100% 8.0
Plu 15:17.5 - 2:17 30.011 0.1 100% 13.7
STELLA
12/15/1989
18:38:37 LT 23:26:38 UT
0:23:59 LST 5:11:59 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Jup 6:31:35 +23:05:14 4.19 46.97 0.58 99.95 -2.53 71.27 13.87
Sat 18:59:09 -22:25:44 10.99 15.07 1.52 99.97 0.32 247.52 -8.65
Ura 18:23:25 -23:36:35 20.34 3.23 2.82 100.00 5.83 252.09 -15.65
Nep 18:46:27 -22:08:36 31.21 1.99 4.33 100.00 7.77 249.71 -10.65
Plu 15:13:13 -02:11:10 30.45 0.27 4.22 99.96 14.03 304.73 -35.08
12/16/1989 0.0hr UT Epoch 2000.0
Jup 6:32.0 23:05 4.182 47.10 100% -2.7
Sat 18:59.5 -22:25 10.949 15.10 " 0.5
Ura 18:20.9 -23:37 20.343 3.40 " 5.8
Nep 18:49.4 -22:06 31.148 2.20 " 8.0
Plu 15:13.7 -02:12 30.404 0.10 " 13.8
STELLA
2/15/1990
18:38:37 LT 23:26:38 UT
4:24:29 LST 9:12:29 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mer 20:30:50 -20:08:19 1.21 5.57 0.17 81.28 0.87 272.99 -34.22
Ven 19:30:07 -15:08:14 0.37 46.20 0.05 19.09 -4.98 289.77 -42.02
Jup 6:03:31 +23:25:49 4.55 43.21 0.63 99.37 -2.33 124.29 62.28
Sat 19:29:31 -21:36:04 10.85 15.26 1.50 99.92 0.29 283.12 -46.39
Ura 18:38:32 -23:26:11 20.04 3.28 2.78 99.96 5.80 293.12 -56.58
Nep 18:55:56 -21:57:06 30.97 2.01 4.29 99.99 7.76 290.44 -52.59
Plu 15:18:08 - 2:05:13 29.50 0.28 4.09 99.93 13.96 24.93 -47.40
2/15/1990 0.0 hrs UT Epoch 2000.0
Mer 20:26.6 -20:18 0.998 5.6 80% -0.2
Ven 19:29.7 -15:05 0.365 45.7 19% -4.6
Jup 06:04.2 23:26 4.538 43.4 100% -2.4
Sat 19:29.6 -21:36 10.814 15.3 100% 0.6
Ura 18:35.8 -23:28 20.037 3.5 100% 5.8
Nep 18:58.8 -21:54 30.931 2.2 100% 8.0
Plu 15:18.6 -02:06 29.505 0.1 100% 13.7
STELLA
2/1/1990
19:28:53 LT 0:16:53 UT
4:15:53 LST 9:03:53 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mar 18:09:37 -24:38:01 2.12 4.42 0.29 95.29 1.59 297.47 -60.80
2/1/1990 0.0hrs UT Epoch 2000.0
Mar 18:07.6 -23:49 2.121 4.4 95% 1.4
STELLA
1/1/1990
19:28:53 LT 0:16:53 UT
2:13:39 LST 7:01:39 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mer 19:48:46 -20:20:23 0.76 8.84 0.11 19.32 0.53 258.46 -17.95
Ven 20:31:34 -16:51:22 0.30 55.72 0.04 9.20 -4.59 254.45 -7.96
1/1/1990 0.0hrs UT Epoch 2000.0
Mer 19:51.3 -20:30 0.782 8.6 23% 0.7
Ven 20:33.4 -16:57 0.291 54.2 10% 4.6
STELLA
12/1/1989
19:28:53 LT 0:16:53 UT
00:15:23 LST 5:03:23 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mer 17:20:31 -25:07:07 1.37 4.92 0.19 94.75 0.90 258.95 -26.33
Ven 19:45:52 -24:09:46 0.49 34.27 0.07 35.59 -4.99 237.38 -0.75
Mar 15:03:29 -18:00:11 2.47 3.80 0.34 98.75 1.99 290.89 -47.04
12/1/1989 0.0 hrs UT Epoch 2000.0
Mer 17:15.6 -24:59 1.376 4.9 95% -0.6
Ven 19:43.9 -24:18 0.500 33.4 36% -4.6
Mar 15:03.0 -16:57 2.469 3.8 99 1.6
STELLA
12/1/1988
19:28:53 LT 0:16:53 UT
00:12:23 LST 5:00:23 UST
Long:72:00:00
Lat:42:00:00
Name R.A. Dec. Dist Size Lhrs Ill. Mag. Alti. Azim.
Mer 16:32:46 -22:47:58 1.45 4.64 0.20 100.00 -1.04 268.07 -33.22
Mar 0:20:13 + 4:59:34 0.72 13.03 0.10 89.90 -0.77 176.76 52.95
12/1/1988 0.0 hrs UT Epoch 2000.0
Mer 16:28.5 -22:34 1.451 4.64 100% -1.2
Mar 0:25.0 2:16 0.712 13.1 90% -0.8