Astro Function Index

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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).
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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 mid-year 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.
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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
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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>
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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.
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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
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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.

 
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