utility
Class Stars

java.lang.Object
  utility.Stars

public class Stars
extends java.lang.Object

Field Summary

static double	DEG_TO_RAD
static double	RADIANS_PER_ARCSEC

Constructor Summary

Stars()

Method Summary

static void	fk5prp(double eqx1, double ra_in, double dec_in, double pma_in, double pmd_in, double par_in, double vel_in, double eqx2, Sixty ra_out, Sixty dec_out, Sixty pma_out, Sixty pmd_out) I stole all this code and ported it from C to Java -Robert Quimby 1999 j.bennett (1992) - Julian precession subroutine using IAU (1976) System of Astronomical Constants Allows precession of proper motion values (also will make use of parallax and radial velocity if not zero.
static double	getArcLength(double ra1, double dec1, double ra2, double dec2) returns the arc length between two points on the sky
static double	getArcLengthGuess(double ra1, double dec1, double ra2, double dec2) returns the arc length between two points on the sky.
static double	getArcLengthTRIG(double ra1, double dec1, double ra2, double dec2) returns the arc length between two points on the sky.
static double	getPAngle(double ha, double dec, double lat) returns the parallactic angle for a position on the sky
static double	getZenithAngle(JulianDate jd, Sixty lat, Sixty longit, double ra, double dec) returns the zenith angle at jd.
static void	main(java.lang.String[] args)
static void	precess(double eqx1, Sixty ra_in, Sixty dec_in, double eqx2, Sixty ra_out, Sixty dec_out) Julian precession subroutine.
static Sixty	raToHA(Sixty ra, double lst) converts RA to HA(-12 to 12)
static void	sph_tri(double ra1, double dec1, double ra2, double dec2, java.util.Hashtable hash) returns the Parallactic angle given hour angle (hrs), dec (degs), and latitude (degs) solve spherical triangle using Napier's analogies the angle A and opposing side a correspond to ra1,dec1 the angle B and opposing side b correspond to ra2,dec2 the angle C and opposing side c correspond to the north celestial pole Code due to Greg Aldering, aldering@mh1.lbl.gov NOTE: returns 180-arc if arc is > 90 degrees.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEG_TO_RAD

public static double DEG_TO_RAD

RADIANS_PER_ARCSEC

public static double RADIANS_PER_ARCSEC

Constructor Detail

Stars

public Stars()

Method Detail

main

public static void main(java.lang.String[] args)

sph_tri

public static void sph_tri(double ra1,
                           double dec1,
                           double ra2,
                           double dec2,
                           java.util.Hashtable hash)

returns the Parallactic angle given hour angle (hrs), dec (degs), and latitude (degs) solve spherical triangle using Napier's analogies the angle A and opposing side a correspond to ra1,dec1 the angle B and opposing side b correspond to ra2,dec2 the angle C and opposing side c correspond to the north celestial pole Code due to Greg Aldering, aldering@mh1.lbl.gov NOTE: returns 180-arc if arc is > 90 degrees.

getArcLengthTRIG

public static double getArcLengthTRIG(double ra1,
                                      double dec1,
                                      double ra2,
                                      double dec2)

returns the arc length between two points on the sky. Uses Napier's rule.

getArcLength

public static double getArcLength(double ra1,
                                  double dec1,
                                  double ra2,
                                  double dec2)

returns the arc length between two points on the sky

getArcLengthGuess

public static double getArcLengthGuess(double ra1,
                                       double dec1,
                                       double ra2,
                                       double dec2)

returns the arc length between two points on the sky. Tries to correct for the dist > 90deg problem.

getZenithAngle

public static double getZenithAngle(JulianDate jd,
                                    Sixty lat,
                                    Sixty longit,
                                    double ra,
                                    double dec)

returns the zenith angle at jd.

getPAngle

public static double getPAngle(double ha,
                               double dec,
                               double lat)

returns the parallactic angle for a position on the sky

raToHA

public static Sixty raToHA(Sixty ra,
                           double lst)

converts RA to HA(-12 to 12)

precess

public static void precess(double eqx1,
                           Sixty ra_in,
                           Sixty dec_in,
                           double eqx2,
                           Sixty ra_out,
                           Sixty dec_out)

Julian precession subroutine. has simpler args than fk5prp() when no proper motions are present. See fk5prp() for comments on method.

fk5prp

public static void fk5prp(double eqx1,
                          double ra_in,
                          double dec_in,
                          double pma_in,
                          double pmd_in,
                          double par_in,
                          double vel_in,
                          double eqx2,
                          Sixty ra_out,
                          Sixty dec_out,
                          Sixty pma_out,
                          Sixty pmd_out)

I stole all this code and ported it from C to Java -Robert Quimby 1999 j.bennett (1992) - Julian precession subroutine using IAU (1976) System of Astronomical Constants Allows precession of proper motion values (also will make use of parallax and radial velocity if not zero. All arguments are double: ra_in, dec_in are input position in radians at eqx1. ra_out, dec_out are output position in radians at eqx2. eqx1 is equinox of input position (in year - e.g. 2000.0) pma_in is proper motion in ra in radians per Julian century. pmd_in is proper motion in dec in radians per Julian century. par_in is parallax in radians (0.0 if none) vel_in is radial velocity in km/sec (0.0 if none) eqx2 is eqinox of output position (in year - e.g. 1992.0) (or 1949.99979 if quick and dirty approx of B1950 desired) pma_out is proper motion in ra in radians per Julian century for eqx2. pmd_out is proper motion in dec in radians per Julian century for eqx2. method from Fricke,W.,Schwan,H.,Lederle,T.,1988,Fifth Fundamental Catalogue (FK5) Part I. (pages 10-11)