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NAME: chdoppler PURPOSE: computes the projected velocity of the telescope wrt four coordinate systems: geo, helio, bary, lsr. negative velocities mean approach the standard LSR is defined as follows: the sun moves at 20.0 km/s toward ra=18.0h, dec=30.0 deg in 1900 epoch coords CALLING SEQUENCE: result = chdoppler( ra, dec, julday, obspos_deg=obspos_deg, path=path, light=light) INPUTS: fully vectorized... ra[n] - the source ra in decimal hours, equinox 2000 dec[n] - the source dec in decimal hours, equinox 2000 julday[n] - the julian day KEYWORDS: /obspos_deg: observatory [lat, wlong] in degrees. default is arecibo. /path - path for the station file. obspos_deg takes precedence. /light - returns the velocity as a fraction of c NOTE: if path is not specified, default long, lat are arecibo. if path is specified, it reads long, lat from the file path + .station OUTPUTS: program returns the velocity in km/s, or as a faction of c if the keyword /light is specified. the result is a 4-element vector whose elements are [geo, helio, bary, lsr]. quick comparison with phil's C doppler routines gives agreement to better than 100 m/s one arbitrary case. REVISION HISTORY: carlh 29oct04. from idoppler_ch; changed calculation epoch to 2000 19nov04: correct bad earth spin calculation 7 jun 2005: vectorize to make faster for quantity calculations.
(See /dzd2/heiles/idl/gen/astro/chdoppler.pro)
NAME: DOPPLER PURPOSE: GIVE DOPPLER VELOCITY KM/S WITH RESPECT TO BARYCENTER AND ALSO LSR. CALLING SEQUENCE: doppler, ra_hrs, dec_deg, equinox, julday, obslongitude, obslatitude, $ v_barycen, v_lsr INPUTS: RA, DEC ARE OF THE SPECIFIED EQUINOX. UNITS ARE DECIMAL HOURS, DEGREES EQUINOX: EQUINOX OF THE RA, DEC, IN YEARS. E.G. 2000. JULDAY: THE JULIAN DAY IN DBL PRECISION, TELLS THE EXACT TIME. OBSLONGITUDE, OBSLATITUDE: OBSERVER'S LONGITUDE, LATITUDE IN DEGREES. LONGITUDE IS WEST LONG, E.G. CALIFORNIA IS +122. IF LATITUDE LT ZERO, IT GIVES VELOCITY OF EARTH'S CENTER. OUTPUTS: V_BARYCEN IS VELOCITY WRT BARYCENTER AND V_LSR IS WRT LSR. NEGATIVE VELOCITIES MEAN APPROACH, OR HIGHER FREQUENCIES FROM THE DOPPLER SHIFT COMMENTS, RESTRICTIONS, ETC: THE LSR IS BASED ON THE CLASSIC RADIO ASTRONOMY ONE, 20 KM/S TOWARDS (RA,DEC)_1900 = (18:00, 30:00) WE NEGLECT THE OBSERVER'S HEIGHT ABOVE SEA LEVEL. THIS ISN'T GOOD FOR HIGH PLACES LIKE MAUNA KEA! ACCURACY SHOULD BE 1 M/S. BASED ON GSFC BARYVEL. TO COMPUTE JULDAY, YOU CAN USE JDCNV. EXAMPLE: GMT 5.5 HRS ON 15-FEB-1994, JDCNV, 1994, 2, 15, 5.5, JULDAY
(See /dzd2/heiles/idl/gen/astro/doppler.pro)
NAME: EQ2AZ PURPOSE: To convert between the HOUR ANGLE-DECLINATION and AZIMUTH-ZENITH ANGLE coordinate systems. CALLING SEQUENCE: EQ2AZ, ha, dec, az, za, latitude [, /REVERSE] INPUTS: latitude - the latitude (a scalar) of the observatory, measured in decimal degrees KEYWORD PARAMETERS: /REVERSE : if this keyword is set, the program takes the azimuth and zenith angle as inputs and returns the hour angle and the declination. The default behavior, as the module name suggests, is to return the azimuth and zenith angle given the hour angle and declination. INPUTS OR OUTPUTS (DEPENDING ON /REVERSE KEYWORD) : ha - hour angle, measured in decimal hours; scalar or array dec - declination, measured in decimal degrees; scalar or array az - azimuth, measured in decimal degrees; scalar or array za - zenith angle (the complementary angle to the elevation), measured in decimal degrees; scalar or array COMMON BLOCKS: None. RESTRICTIONS: Hour angle must be given in decimal hours. Declination, azimuth, zenith angle, and latitude must be given in decimal degrees. EXAMPLE: Find the azimuth and zenith angle of Altair [RA (J2000): 19 50 47 Dec (J2000): 08 52 06] at LST 19h at Arecibo [LONG: 66 45 10.8 LAT: 18 21 14.2] IDL> eq2az, 19.0-ten(19,50,47), ten(08,52,06), az, za, $ IDL> ten(18,21,14.2) IDL> help, az, za AZ DOUBLE = 125.90073 ZA DOUBLE = 15.549609 NOTES: Went through pain to assure that if a scalar is input, a scalar is returned, but even more pain to allow multi-dimensional arrays to be input (and to make the output have the same dimensions!) Also, if inputs are double precision, the calculations will be done in double precision. The azimuth is returned in the range 0 -> 360 degrees. MODIFICATION HISTORY: 20 May 2004 Written by Tim Robishaw, Berkeley
(See /dzd2/heiles/idl/gen/astro/eq2az.pro)
NAME: eqtoaz -- CONVERT HA, DEC TO AZ, ZA or vice versa CONVERT HA, DEC TO AZ, ZA IF DIRECTION=+1 CONVERT AZ, ZA TO ZA, DEC IF DIRECTION=-1 HA, DEC ARE IN DECIMAL HRS, DEG AZ, ZA ARE IN DECIMAL DEG, DEG IN COMMON ANGLESTUFF, OBSLONG AND OBSLAT ARE ASSUMED TO BE IN DEGREES.
(See /dzd2/heiles/idl/gen/astro/eqtoaz.pro)
NAME: LDS PURPOSE: EXPLANATION: CALLING SEQUENCE: INPUTS: OPTIONAL INPUTS: OUTPUTS: OPTIONAL OUTPUTS: KEYWORDS: COMMON BLOCKS: SIDE EFFECTS: RESTRICTIONS: PROCEDURES CALLED: PLOTSPECTRUM ZOOMIN AVERAGE TZOOMIN FITSPEC PS_SPEC_EVENT PS_SPEC SELECT_EVENT SELECT ROUNDTOHALF VTOBIN GETMEAN CUTOFF MODEL INDIPLOT CLEAR FITLDS EDGECORRECTION GFIT GCURV EXAMPLE: NOTES: RELATED PROCEDURES: MODIFICATION HISTORY: Written Tim Robishaw, Berkeley
(See /dzd2/heiles/idl/gen/astro/lds.pro)
NAME: LSRVEL -- give LSR velocity towards an ra, dec PURPOSE: GIVE THE COMPONENT OF LSR VELOCITY TOWARDS THE GIVEN ELL, BEE 'LSR' MOVES WITH 20.000 KM/S TOWARDS ra1900, dec1900 = 18.000, 30.000 CALLING SEQUENCE: LSRVEL, RA_EPOCH, DEC_EPOCH, EQUINOX, VLSR INPUTS: RA_EPOCH: the R.A. of the position, DECIMAL HOURS. DEC_EPOCH, THE DEC IN DECIMAL DEGREES. EQUINOX: THE EQUINOX OF THE POSITIONS, E.G. 2000. OUTPUTS: DELVLSR: the velocity in the LSR frame. HISTORY: Written by Carl Heiles. 12 JUN 2000. IF YOU NEED TO CONVERT FROM GALACTIC TO EQUATORIAL BEFORE ENTERING THIS: CONVERT INPUT GALACTIC COORDS TO 1900 EPOCH EQUATORIAL COORDS... glactc, ra1900, dec1900, 1900.0, ell, bee, 1
(See /dzd2/heiles/idl/gen/astro/lsrvel.pro)
NAME: MAKE_LDS_CUBE PURPOSE: To make an (l,b,v) cube of a subset of the Leiden/Dwingeloo Survey of Galactic neutral hydrogen. CALLING SEQUENCE: make_lds_cube, lcen, bcen, dl, db [, VRANGE=[min,max]] [, FILENAME=string] INPUTS: lcen - central Galactic longitude of cube [degrees] bcen - central Galactic latitude of cube [degrees] dl - the half-width of the cube in the longitude direction[degrees] db - the half-width of the cube in the latitude direction [degrees] KEYWORD PARAMETERS: VRANGE = 2-element vector with minimum and maximum VLSR velocities [km/s] in the cube. Default is to use entire velocity range. FILENAME = name of the output FITS file. Default is to write to a file named lds_cube.fits in the current working directory. OUTPUTS: None. COMMON BLOCKS: None. SIDE EFFECTS: A FITS cube is written. PROCEDURES CALLED: TABINV, FITS_ADD_AXIS_PAR EXAMPLE: IDL> make_lds_cube, 90, 0, 30, 10, VRANGE=[-100,100] MODIFICATION HISTORY: 15 Sep 2004 Written by Tim Robishaw, Berkeley
(See /dzd2/heiles/idl/gen/astro/make_lds_cube.pro)
NAME: modangle360 -- CONVERT ANGLES TO THE INTERVAL 0 TO 360 DEG. CONVERT ANGLES TO THE INTERVAL 0 TO 360 DEG. ALL ANGLES ARE IN DEGREES. if negpos is set, interval is -180 to 180
(See /dzd2/heiles/idl/gen/astro/modangle360.pro)
NAME spherical1_to_spherical2 -- CONVERTS LONGITUDE AND LATITUDE between 2 systems purpose: CONVERTS LONGITUDE AND LATITUDE IN SYSTEM 1 TO THOSE IN SYSTEM 2 USES THE ROTATION MATRIX RTOT ALL ANGLES ARE IN ***DEGREES***. VECTORIZED BUT REUTNRS ALL INPUTS IN 1-D.
(See /dzd2/heiles/idl/gen/astro/spherical1_to_spherical2.pro)
NAME: vtobin PURPOSE: Finds the bin number(s) in a velocity vector closest to some v. CALLING SEQUENCE: bin = vtobin(vlsr, v) INPUTS: vlsr : velocity vector v : velocity or velocities whose corresponding bins you want REVISION HISTORY: 17-Nov-2000 Written T. Robishaw, Berkeley
(See /dzd2/heiles/idl/gen/astro/vtobin.pro)