/astro October 2009 This directory includes about 80 mostly self-contained astronomy utilities. The procedure UVBYBETA uses the non-standard system variable !TEXTOUT. The procedure ASTROLIB can be used to add this system variable to one's session. The routines JPLEPHREAD and JPLEPHINTERP require a FITS file containing a JPL (Jet Propulsion Laboratory) ephemeris for solar system bodies. A copy of the DE405 ephemeris FITS file JPLEPH.405 is available in http://idlastro.gsfc.nasa.gov/ftp/data/ but note that this file is not included in the IDL Astronomy Library tar files. Additional time conversion procedures such as those to convert between Julian date and International Atomic Time (TAI) are located in http://sohowww.nascom.nasa.gov/solarsoft/gen/idl/time Also see the utility procedure CMSYSTIME() in http://astrog.physics.wisc.edu/~craigm/idl/misc.html#CMSYSTIME Astronomical Utilities pro/astro ________ A_b() - Compute B band interstellar extinction as a function of Galactic coords. ADSTRING() - Format RA and DEC as a character string AIRTOVAC - Convert air wavelengths to vacuum wavelengths AITOFF - Convert longitude,latitude to X,Y using Aitoff equal-area projection AITOFF_GRID - Create an overlay grid using the AITOFF projection ALTAZ2HADEC - Convert Horizon (Alt-Az) coordinates to Hour Angle and Declination ARCBAR - Draw an arcbar over an image showing the astronomical plate scale ARROWS - Given a FITS header, display a "weathervane" showing N-E orientation ASTDISP - Display formatter for pixel + astronomical coordinates ASTRO - Interactive driver to compute astronomical precession, or coordinate conversions (calls EULER and PRECESS). BARYVEL - Compute components of barycentric Earth velocity, given Julian date BPRECESS - Precess coordinates, proper motion from J2000 to B1950 CALZ_UNRED - Deredden a galaxy spectrum using the Calzetti et al. (2000) formula CCM_UNRED - Deredden a spectrum using the Cardelli, Clayton and Mathis (1989) parameterization. CO_ABERRATION - Calculate changes to Ra and Dec due to aberration effects CO_NUTATE - Calculate changes in RA and Dec due to nutation of the Earth's rotation CO_REFRACT() - Calculate correction to altitude due to atmospheric refraction COSMO_PARAM - Derive a full set of cosmological parameters given a subset CT2LST- Convert from civil time to local sidereal time DATE() - Convert day of year to a DY-MON-CCYY string (FITS standard) DATE_CONV() - Function to perform various date format conversions DAYCNV- Convert from Julian Date to calendar date. DEREDD- Deredden Stromgren indices (called by UVBYBETA) ECI2GEO() - Convert Earth-centered inertial coordinates to geographic coords EQ2HOR - Convert celestial (ra-dec) coords to local horizon coords (alt-az). EQPOLE - Convert longitude,latitude to X,Y using polar equal-area projection EQPOLE_GRID - Create overlay grid using polar equal-area projection EULER - Astronomical coordinate system conversions FLUX2MAG() - Convert from flux units to magnitudes FM_UNRED - Deredden a spectrum using the Fitzpatrick & Massa (1998) parameterization. GAL_UVW - Calculate the Galactic space velocity (U,V,W) of a star GAL_FLAT() - Correct a galaxy image for inclination effects. GALAGE - Derive a galaxy age as a function of redshift for a cosmological model GCIRC - Compute rigorous great circle distance GEO2ECI() - Convert geographic coordinates to Earth-centered inertial coords GEO2GEODETIC() - Convert from geographic to geodetic coordinates GEO2MAG() - Convert from geographic to geomagnetic coordinates GEODETIC2GEO() - Convert from geodetic to geographic coordinates GET_COORDS - Read in angular input in decimal or sexigesimal format GET_DATE - Get the current date in CCYY-MM-DD format (FITS standard) GET_JULDATE - Get the current Julian date as a double precision scalar GLACTC- Convert between Galactic and equatorial coordinates at any equinox GLACTC_PM - Convert between celestial and Galactic (or Supergalactic) proper motion HADEC2ALTAZ - Converts Hour Angle and Declination to Horizon (alt-az) coordinates HELIO - Compute (low-precision) heliocentric coordinates of the planets HELIO_JD() - Convert geocentric (reduced) Julian date to heliocentric Julian date HELIO_RV() - Compute radial velocity given binary star orbit parameters HOR2EQ - Convert local horizon coords (alt-az) to equatorial (ra-dec). IMCONTOUR - Contour plots with astronomical labeling (either RA,Dec or arc distance from the image center IMF() - Return values for a multi-component power law initial mass function ISMEUV() - Compute EUV optical depth due to photoionization of HI, HeI and HeII JDCNV - Convert from calendar date to Julian date. JPLEPHINTERP - Interpolate position and motion of planetary bodies (JPL Ephemeris) JPLEPHREAD - Open and read JPL DE200 or DE405 Ephemeride FITS File JPRECESS - Precess positions & proper motions from B1950 to J2000 JULDATE-Convert from calendar date to reduced Julian date. LSF_ROTATE - Create a 1-d convolution kernel to broaden a spectrum from a rotating star LUMDIST - Return luminosity distance for a given redshift & cosmological model MAG2GEO() - Convert from geomagnetic to geographic coordinates MAG2FLUX() - Convert from magnitudes to flux units MONTH_CNV() Convert a month name to the equivalent number or vice-versa MOONPOS- Compute the RA and Dec (and distance) of the Moon at a given date MPHASE - Compute illuminated fraction of the Moon's disk for given Julian dates NUTATE - Compute the nutation in longitude and latitude for given Julian date(s) OBSERVATORY - Return coordinates, altitude & time zones of an observatory PLANCK() - Returns a blackbody flux for a given effective temperature PLANET_COORDS - Return low-precision RA and Dec of planets give a date(s) POSANG - Compute the position angle between sources of specified RA and Dec PRECESS - Precess RA and Dec to a new equinox PRECESS_CD - Precess the PC (or CD) matrix in a FITS header to a new equinox PRECESS_XYZ - Precess equatorial geocentric rectangular coordinates PREMAT() - Returns precession matrix from equinox 1 to equinox 2 QDCB_GRID - Create overlay grid using COBE quad cube database coordinates RADEC - Format RA, Dec as Hours,Min,Sec,Deg,Min,Sec REDSHIFT - Interactively convert between redshift, distance, and velocity (in /jhuapl) SIXTY - Convert decimal number to sexigesimal SPHDIST() - Find angular distance on a sphere (in /jhuapl) SUNPOS - Compute the RA and Dec of the Sun at a given date TDB2TDT() - Relativistic clock corrections due to Earth motion in solar system TEN() - Convert sexigesimal number to decimal TENV() - Like TEN but will work on a vector of sexigesimal numbers. TICPOS - Specify distance between tic marks for astronomical coordinates TICLABELS - Create labels for astronomical coordinate tick marks TICS - Compute the optimum distance between tic marks for astronomical labeling TIC_ONE - Determine optimum position of the first tic in astronomical labeling UVBYBETA - Use Stromgren indices to derive dereddened colors, metallicity, and effective Temperature. VACTOAIR - Convert vacuum wavelengths to air wavelengths. WFPC2_METRIC - Compute the distortion in a WFPC2 image and return coordinates XYZ - Compute heliocentric rectangular coordinates at given Julian date. YMD2DN() - Convert year,month,day to day number of the year (in /jhuapl) YDN2MD - Convert day number of the year to year, month,day ZANG() - Compute angular size as a function of redshift in a Friedman cosmology ZENPOS - Compute the RA and Dec of the local zenith at a given date