Astro Function Index
Basic Conversions
Normalize
Values to be Within Specified Max Value
<float>
Keep degrees within 360, hours within 24, etc. Max can be negative.
Day
Decimal to Day, Hour, Min and Second Format
<DAY>
1] The first four equations generate one
component of Day:Hr:Min:Sec
<HR>
2]
<MIN>
3]
<SEC>
4]
<Mat>
Executes all four equations to display
Day:Hr:Min:Sec in a formatting matrix.
Day,
Hour, Min and Sec to Day Decimal Notation
<DAYDec>
Convert input time into a decimal number of days.
<Mat>
Input one row matrix (a vector) of above arguments.
Decimal
Degrees to Deg, Min and Sec of Arc
<DEG>
1] The first three equations generate one component of Deg:Min:Sec
<MIN>
2]
<SEC>
3]
<Mat>
Executes all three equations to display Deg:Min:Sec in a formatting
matrix.
Deg,
Min and Sec of Arc to Decimal Degrees
<DEGDec>
Input DEG, MIN, SEC and get back decimal degrees
<Mat>
Input one row matrix (a vector) of above arguments.
Degrees
of Arc to Right Ascension and Time Units of Hours, Minutes and Sec
<HR>
1] The first three equations generate one component of Hr:Min:Sec
<MIN>
2]
<SEC>
3]
<Mat>
Executes all three equations to display Hr:Min:Sec in a formatting matrix.
Right
Ascension and Time Units to Decimal Degrees
<RA>
Input HR, MIN, SEC and get RA in decimal format
<Mat>
Like above but uses one row matrix (a vector) of above arguments.
Mean
Solar Day to Sidereal Day
<DAYDec>
Get inverse by dividing Sidereal Day by MEANDay2SIDDay(1).
Date
Conversions
Gregorian
or Julian Calendar Date to Julian Day Count
<JD>
IsGreg flag sets conversion: 1=Gregorian, any other value for Julian
<JD>
Gregorian to Julian Day count only
<JD>
Gregorian decimal Year to Julian Day. Find JD for midyear Epoch, i.e.:
J1999.5
Julian Day Count to Gregorian
or Julian Calendar Date
<MTH>
1] First three return Mth/Day/Year. Conversion type set by IsGreg flag.
<DAYDec>
2] IsGreg flag must be same on all 3: 1 = auto, 0 = Julian, 1 =
Gregorian
<YR>
3]
<Mat>
Executes all three equations to display Yr:Mn:Dy in a formatting matrix.
<YRDec>
Julian day count to decimal year. Find epoch (J1999.23) from JD.
Julian Day Count to Gregorian
Calendar Date
<DAYDec>
1] Execute first three to get Mth/Day/Year  Gregorian calendar only.
<MTH>
2]
<YR>
3]
<Mat>
Executes all three equations to display Yr:Mn:Dy in a formatting matrix
Julian Day Count to Julian
Centuries from J2000
<JC>
Will be negative for dates prior to J2000.
Returns Julian Day Number at
0.0 UT for a Given Julian Day Count
<JD>
Returns JD at start of civil day.
Sidereal Time Conversions
Greenwich Mean and Apparent Sidereal Time for Julian Day Date in
Degrees of Arc
<DEGDec>
IsMean sets conversion type: 1 = GMST to UT, else GAST to UT
<DEGDec>
GMST to UT only
<DEGDec>
GAST to UT only
Local Mean and Apparent Sidereal Time for Julian Day Date in Degrees
of Arc
<DEGDec>
IsMean sets conversion type: 1 = LMST at JD, else LAST at JD
<DEGDec>
LMST at specified JD and Longitude
<DEGDec>
LAST at specified JD and Longitude
UT for Local Mean and Apparent Sidereal Time for Julian Day Date in
Degrees of Arc
<DEGDec>
IsMean sets conversion type: 1 = LMST, else LAST
<DEGDec>
Convert LMST to UT. LONG = 0 yields UT for Greenwich ST
<DEGDec>
Convert LAST to UT
<Mat>
Handles repeated Sidereal Time in civil day by displaying Hr:Min:Sec in
two rows
Precession,
Nutations, and Obliquity of the
Ecliptic
Precession from Initial Epoch Julian Day Date to Final Epoch Julian
Day Date
<RA>
In: RA, DEC and JD of initial
and final epoch, out: precessed RA
(deg)
<DEC>
In: RA, DEC and JD of initial
and final epoch, out: precessed DEC
(deg)
<DEC>
Alternate form of (),
see text.
Nutation in Longitude and Obliquity of the Ecliptic for a Given
Julian Day Date
<SEC>
Input is Julian Century (use JCJ2000()), output Nutation in Longitude.
<SEC>
Input is Julian Century (use JCJ2000()), output Nutation in Obliquity.
Mean and True Obliquity of the Ecliptic for a Given Julian Day Date
<DEGDec>
Input is Julian Century (use JCJ2000()), output Obliquity in degrees.
<DEGDec>
Altitude, Azimuth, Local Hour Angle, Right
Ascension and Declination
Altitude and Azimuth of Object to Local Hour Angle of Observer
<DEGDec>
See also RA2LHA() version below.
Apparent Right Ascension and Declination from Object's
Altitude/Azimuth, Observer's
Latitude/Longitude and UT Time and Julian Day Date
<RA>
RA equation
<DEGDec>
DEC equation
Right Ascension to Local Hour Angle
<DEGDec>
See also AA2LHA() version above.
Ecliptic and Equatorial Coordinate
Transformations
Coordinate Transform Between Equatorial and Ecliptic Systems
<DEGDec>
Ecliptic Long for true or mean equinox on JD from RA and DEC
<DEGDec>
Ecliptic Latitude for true or mean equinox on JD from RA and DEC
<RA>
Right Ascension in true or mean equinox on JD from LAT and LONG
<DEGDec>
Declination in true or mean equinox on JD from LAT and LONG
Object Coordinates and Phenomena Calculation
Star Data Matrix
Each row contains data on one star.
First data row = 1. User can add new star rows.
Star Data Extraction
<string>
Star name
<YRDec>
Epoch year of star data
<RA>
RA of star in decimal degrees
<DEGDec>
DEC of star in decimal degrees
<float>
Proper motion in arc seconds per year
<float>
Proper motion in arc seconds per year
Planet Data Matrix
Each row contains data on one planet. First data row = 1. User can add
new data rows.
Low Precision Helio and Geocentric Longitudes
of the Planets
<DEGDec>
Heliocentric longitude for planet on date
<DEGDec>
Geocentric longitude for planet on date
Low Precision Sidereal Time of Rising and
Setting
<string>
String indicates if rise or set is possible.
<RA>
Sidereal time of object rising in units of degrees.
<RA>
Sidereal time of object setting in units of degrees.
Reference to Access All Functions
Astro
Utilities Electronic Book Copyright © 1999 Pietro
Carboni. All rights reserved.
EBook
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