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PC-SIG Diskette Library (Disk #1614)
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Information about “SKYCLOCK”
A unique program, SKYCLOCK is an historical astronomical ephemeris and
data conversion program. Unlike most other astronomical ephemeris
programs, this program works with dates of both the Julian and Gregorian
calendars and dates A.D. and B.C. SKYCLOCK can also calculate the
positions of the visible astrological houses for a specific date. Thus
SKYCLOCK can be used for both astronomical and astrological purposes.
With SKYCLOCK you may also automatically convert dates between several
calendars used at different times throughout history. On what day did
Julius Caesar die according to the Roman calendar? With SKYCLOCK you
can find out.
As an astronomical ephemeris, SKYCLOCK allows you to calculate the
positions of the sun, moon, planets, stars, comets, and astrological
houses for any date back to several centuries B.C. You must first enter
the date and time and the latitude and longitude of your desired
observation point. You may optionally have the date and time
automatically entered from DOS, and the time entered may be according to
five different time standards. SKYCLOCK then lists all the time
variable elements entered, and the position of the celestial body. For
the planets, SKYCLOCK lists the heliocentric and geocentric longitude
and latitude, its perihelion, the right ascension, the declination, the
azimuth, the altitude, the phase angle, elongation from the sun, the
distance to the sun, and the distance to the earth. Other specific
information is included for the sun, moon, comets and stars. SKYCLOCK
can also list summary information of the positions for the sun, moon,
and all the planets for a specific date all at once. For calculating
the positions of the visible astrological houses, you must also enter
the longitude of mid-heaven, the geographical latitude, and the
obliquity of the ecliptic. SKYCLOCK will then list the positions of the
visible astrological houses according to nine different systems used
throughout history.
SKYCLOCK is not only an astronomical ephemeris, but also a calendar date
conversion program. SKYCLOCK allows you to easily convert dates between
nine different calendars used throughout history. These include the
Julian, Gregorian, Egyptian, Alexandrian, Roman, Nabonassar, Islamic,
French, and Zodiacal calendars. For converting dates between the
calendars you may enter either the date or the Julian day number.
SKYCLOCK will then list the Julian day number, the day of the week, the
age of the moon, and the Roman indiction. You may also find the date of
Easter Sunday and the date of lunar epact according to both Julian and
Gregorian calendars.
CLOCK1.DOC
CLOCK
A date conversion program
This program will assist in converting dates from
one calendar to another, in finding the date of Easter and
in determining the lunar epact. This version 1.0 is still
rather sketchy and suggestions pertaining to uncovered
calendars (especially algorithms permitting derivation of
the Julian Day number from a date or a date from the Julian
day number) are welcomed.
CLOCK2.DOC
The Various Calendars
The program will assist in converting dates
between different calendars. Calendars implemented in this
version of the program (1.0) are the Julian, Gregorian,
ancient Egyptian, Alexandrian (and later Coptic), ancient
Roman, Nabonassar (used by ancient astronomers), Islamic,
French Revolutionary, and Zodiacal. The user enters the
year (according to the specific era, using Roman or Arabic
numerals), the month and the day, but the Julian day number
can also be used. In the case of the old, pre-Julian Roman
calendar, whose course is still being debated, a selection
of scholarly theories is presented.
The information provided by the program contains,
besides the obvious date conversions, the Julian day number,
the day of the week, the age of the moon (both
astronomically and in the first centuries of our era,
according to papyrus Carlsberg 9), the Roman indiction, and
other information pertaining to this particular historical
period.
CLOCK3.DOC
Easter Date Determination
The date of Easter is given for any year in the
Julian Calendar, and for the western rite, after 1582 in the
Gregorian calendar.
The author of this program would like to expand
this section by providing as well the date of Passover.
Suggestions on how to compute this are welcomed.
CLOCK4.DOC
The Lunar Epact
The lunar epact represents the age of the moon at
the beginning of the year on January 1. Various systems
were historically devised to compute it; in this particular
version of Clock (1.0), the systems proposed by Augustalis,
Cassiodorus and Gregory VII are being implemented.
FILE1614.TXT
Disk No: 1614
Disk Title: Skyclock
PC-SIG Version: S1
Program Title: Skyclock
Author Version: 1.00
Author Registration: $25.00
Special Requirements: None.
A unique program, SKYCLOCK is a historical astronomical ephemeris and
data conversion program. Unlike most other astronomical ephemeris
programs, this program works with dates of both the Julian and Gregorian
calendars and dates A.D. and B.C. SKYCLOCK can also calculate the
positions of the visible astrological houses for a specific date. Thus
SKYCLOCK can be used for both astronomical and astrological purposes.
With SKYCLOCK you may also automatically convert dates between several
calendars used at different times throughout history. On what day did
Julius Caesar die according to the Roman calendar? With SKYCLOCK you
can find out.
As an astronomical ephemeris, SKYCLOCK allows you to calculate the
positions of the sun, moon, planets, stars, comets, and astrological
houses for any date back to several centuries B.C. You must first
enter the date and time and the latitude and longitude of your desired
observation point. You may optionally have the date and time
automatically entered from DOS, and the time entered may be according
to five different time standards. SKYCLOCK then lists all the time
variable elements entered, and the position of the celestial body. For
the planets, SKYCLOCK lists the heliocentric and geocentric longitude
and latitude, its perihelion, the right ascension, the declination, the
azimuth, the altitude, the phase angle, elongation from the sun, the
distance to the sun, and the distance to the earth. Other specific
information is included for the sun, moon, comets and stars. SKYCLOCK
can also list summary information of the positions for the sun, moom,
and all the planets for a specific date all at once. For calculating
the positions of the visible astrological houses, you must also enter
the longitude of Mid-Heaven, the geographical latitude, and the
obliquity of the ecliptic. SKYCLOCK will then list the positions of
the visible astrological houses according to nine different systems
used throughout history.
SKYCLOCK is not only an astronomical ephemeris, but also a calendar
date conversion program. SKYCLOCK allows you to easily convert dates
between nine different calendars used throughout history. These
include the Julian, Gregorian, Egyptian, Alexandrian, Roman,
Nabonassar, Islamic, French, and Zodiacal calendars. For converting
dates between the calendars you may enter either the date or the Julian
day number. SKYCLOCK will then list the Julian day number, the day of
the week, the age of the moon, and the Roman indiction. You may also
find the date of Easter Sunday and the date of lunar epact according to
both Julian and Gregorian calendars.
File Descriptions:
USER INI Initialization file.
SKY EXE Astronomical ephemeris program.
STARCAT DAT Star catalog file.
CLOCK EXE Calendar date conversion program.
SKY2 ??? On-line help file.
CLOCK1 ??? On-line help file.
SKYCLOCK EXE Main program.
READ ME Program introduction.
PC-SIG
1030D East Duane Avenue
Sunnyvale Ca. 94086
(408) 730-9291
(c) Copyright 1988 PC-SIG, Inc.
GO.TXT
╔═════════════════════════════════════════════════════════════════════════╗
║ <<<< Disk #1614 SKYCLOCK >>>> ║
╠═════════════════════════════════════════════════════════════════════════╣
║ To start SKYCLOCK, type: SKYCLOCK (press return) ║
║ ║
║ To print documentation, type: COPY SKY*.DOC PRN (press enter) ║
║ COPY CLOCK*.DOC PRN (press enter) ║
╚═════════════════════════════════════════════════════════════════════════╝
SKY1.DOC
"Sky"
An electronic ephemeris
"Sky" is written by Pierre Brind'Amour, a
professor in the Department of Classical Studies at the
University of Ottawa (Canada); his field of research is
ancient chronology, the evolution of calendars and the
history of astronomy and astrology. This historical
background is reflected in the program which can be run for
dates B.C. as well as A.D. The claimed accuracy (positions
are given to the nearest minute of arc), except for recently
discovered planets that are invisible to the naked eye,
extends to several centuries B.C. Other historical features
are the possibility of entering the program with Sundial
Time, also of using "M", the ratio of the length of the
longest day to the shortest, as an expression of
geographical latitude, and the display of ecliptic
coordinates in addition to equatorial coordinates for the
stars.
This version 1.0 of the program has been designed
for ease of use rather than for accuracy. One can get, for
example, the position of various stars, planets and comets
for the same time and place variables, or one can vary data
from the time and place variables in order to study the
movement of a particular celestial body.
Improvements considered for future versions of the
program are increased precision (to arc sec and beyond) and
what goes with it (use of Dynamical Time for example),
addition of a Messier object catalog, search of stars by
name or by position, position of the Galilean satellites of
Jupiter, an improved and amplified on-disk manual, a
tutorial on Positional Astronomy, etc.
SKY2.DOC
The Time Variable
The program aims at providing the position of
celestial bodies for a certain point in time and as seen
from a certain location; therefore, information relative to
this particular instant and this location has to be provided
by the user.
Year, month and day are entered according to
normal practice. The calendar used is the Julian calendar
for dates until October 5, 1582, and the Gregorian calendar
afterwards.
The time of the day is entered as "hour min"
counted from midnight (hence 14h = 2 p. m.). The time scale
is either Ephemeris Time, Universal Time, Mean Local Time,
Standard Time (for wich you have to provide the Time Zone)
or Sundial Time.
Geographical longitude and latitude are entered as
decimal angles (DDD.dd). "M" can also be used; this was an
ancient way to determine latitude, by the ratio of the hours
of daylight to twelve hours at the summer solstice. If "M"
is not available, just enter two dashes "--". If "M" is
available and entered, it will override the geographical
latituded entered earlier.
Finally, you might want to enter a note of some
sort for future reference if a printout of the screen is
needed.
The program will display on a single screen the
information already entered, plus a number of time
conversions and other related information.
All input data provided by the user are kept into
memory for further runs of the program. If one wishes, one
can go over again the input data routine and change only
selected variables.
SKY4.DOC
Comets
This part of the program computes the position of
a comet at a given point in time and as seen from a given
location. No cometary catalog is provided, so the user must
enter the usual initial elements. A good source for these
is the "Catalog of Cometary Orbits", by Brian G. Marsden,
Hillside, New Jersey, Enslow Publishers, 1983.
Having run the comet routine, one can return to
the Main Menu and make changes in the time and place
variable, and then come back and run the comet routine
again, without the need to reenter the initial elements.
Cometary positions are provided for the equinox of date, but
also for the equinox of 1950.0, in order to facilitate the
comparison with star catalogs.
SKY5.DOC
Stars
The program reads from a catalog of several
hundreds of the brightest stars. The user can scroll
through it and make his/her selection. Star names are given
with the traditional Greek denomination (example: "ALP LIB"
= "Alpha Librae"), followed by the standard Arabic name
("ZUBENELG" = "Zubenelgenubi") and the DM number ("-15
3966"). The catalog is a selection from the "STAR1" catalog
provided with the U. S. Naval Observatory "Floppy Almanac"
(v. 1.50.88). The catalog is an ordinary ASCII file and can
be altered or amplified by the user; one can also
substitute it with another catalog using the same format.
The user can also enter the program by providing
his or her own information relative to any star; needed are
the name of the star, its Right Ascension 1950.0 or 2000.0,
its Declination 1950.0 or 2000.0 and its proper motions in
Right Ascension and Declination in arc seconds per century;
parallax, radial velocity and visual magnitude are not
necessary but can be entered as well to provide a fuller
picture.
One can leave the star routine and make changes to
the time and place input, and then return to the star
routine without having to reenter star information or scroll
through the catalog. Star positions are displayed for both
the 1950.0 equinox and the 2000.0 equinox, in addition to
the equinox of date.
SKY6.DOC
Astrological Houses
According to ancient astrological theory, the
Heavens are divided into twelve significant regions in the
plane of the Observer, numbered from the first, called the
Ascendant, rising in the East, and counted in the order of
the signs of the Zodiac. These twelve "houses" are fixed
and the Heavens appear to rotate entirely through them in
the course of one day. Primitive astrologers probably did
not suspect the geometrical problems posed by the doctrine
and were satisfied with the so-called "Equal House System."
Soon enough, various solutions were proposed; the program
offers a nearly complete survey of these.
The "Equal House System" divides the Ecliptic into
twelve equal houses counted from the Ascendant.
The "Porphyrius System" named after the Neo-
Platonic philosopher Porphyry (233-303) divides equally the
regions of the Ecliptic comprised in the quadrants formed by
the four cardinal points (Ascendant, Lower Mid Heaven,
Descendant, Mid Heaven). In this system, as in most others,
Mid Heaven stands on the cusp of the tenth house.
The "Old Greek System" (also called the
"Alcabitius System") divides equally the regions of the
Equator comprised between the four cardinal points; the
houses are then projected unto the Ecliptic.
The "Regiomontanus System", made famous by a
Fifteenth Century German mathematician (1436-1476), and the
"Campanus System", whose attribution is not clear and whose
date is either the Thirteenth or the Fifteenth Century, try
to reconcile the fact that Mid Heaven is independant from
the local plane and the Ascendant is dependant upon it.
Probably the system most widely used by modern
astrologers is the so called "Placidus System", called after
a Seventeenth Century Italian monk (1603-1668), but already
proposed a century earlier by the Italian mathematician
Magini. It divides equally the time taken by the point on
the Ascendant to reach Mid Heaven; and so on for the other
quadrants.
The "Morinus System" is named after Jean-Baptiste
Morin (1583-1656), French astrologer to the court of Louis
XIV; it divides the Equator in twelve equal segments from
the point where it intersects the local plane. In this
system, the Ascendant does not coincide with the cusp of the
first house, and except for places on the Equator, Mid
Heaven does not coincide with the cusp of the tenth house.
The "Meridian System" divides the Equator equally
from Mid Heaven; the system is independant from the local
plane and the Ascendant does not fall on the first house
cusp.
The "Koch System" is named after Walter Koch
(1895-1970); it is also a system of time division, where
the time taken for a point at Mid Heaven to reach one third
of the semi-diurnal arc is allocated to the point on the
Ascendant for it to rise and mark the cusp of the eleventh
house.
All that is needed in order to enter this part of
the program is the longitude of Mid Heaven, the latitude of
a given place and the obliquity of the Ecliptic. If other
parts of the program have previously been executed, these
values are already computed and available.
Directory of PC-SIG Library Disk #1614
Volume in drive A has no label
Directory of A:\
CLOCK EXE 29584 8-11-88 1:04a
CLOCK1 DOC 603 8-12-88 2:09a
CLOCK2 DOC 1340 8-12-88 2:02a
CLOCK3 DOC 479 8-12-88 2:07a
CLOCK4 DOC 429 8-12-88 2:10a
FILE1614 TXT 5033 10-16-89 9:07p
GO BAT 38 1-01-80 1:56a
GO TXT 617 10-18-89 1:00p
READ ME 1053 8-12-88 12:39a
SKY EXE 127744 8-15-88 12:29a
SKY1 DOC 2270 8-12-88 1:40a
SKY2 DOC 2171 8-12-88 12:38a
SKY3 DOC 6404 8-12-88 2:29a
SKY4 DOC 995 8-12-88 2:31a
SKY5 DOC 1845 8-12-88 1:34a
SKY6 DOC 4246 8-12-88 1:48a
SKYCLOCK EXE 12960 11-30-88 12:05a
STARCAT DAT 100940 8-11-88 12:32a
USER INI 23 8-12-88 12:49a
19 file(s) 298774 bytes
13312 bytes free