From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- math/slalib/doc/de2h.hlp | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 math/slalib/doc/de2h.hlp (limited to 'math/slalib/doc/de2h.hlp') diff --git a/math/slalib/doc/de2h.hlp b/math/slalib/doc/de2h.hlp new file mode 100644 index 00000000..7e5bcb06 --- /dev/null +++ b/math/slalib/doc/de2h.hlp @@ -0,0 +1,59 @@ +.help de2h Jun99 "Slalib Package" +.nf + + SUBROUTINE slDE2H (HA, DEC, PHI, AZ, EL) + + - - - - - + D E 2 H + - - - - - + + Equatorial to horizon coordinates: HA,Dec to Az,El + + (double precision) + + Given: + HA d hour angle + DEC d declination + PHI d observatory latitude + + Returned: + AZ d azimuth + EL d elevation + + Notes: + + 1) All the arguments are angles in radians. + + 2) Azimuth is returned in the range 0-2pi; north is zero, + and east is +pi/2. Elevation is returned in the range + +/-pi/2. + + 3) The latitude must be geodetic. In critical applications, + corrections for polar motion should be applied. + + 4) In some applications it will be important to specify the + correct type of hour angle and declination in order to + produce the required type of azimuth and elevation. In + particular, it may be important to distinguish between + elevation as affected by refraction, which would + require the "observed" HA,Dec, and the elevation + in vacuo, which would require the "topocentric" HA,Dec. + If the effects of diurnal aberration can be neglected, the + "apparent" HA,Dec may be used instead of the topocentric + HA,Dec. + + 5) No range checking of arguments is carried out. + + 6) In applications which involve many such calculations, rather + than calling the present routine it will be more efficient to + use inline code, having previously computed fixed terms such + as sine and cosine of latitude, and (for tracking a star) + sine and cosine of declination. + + P.T.Wallace Starlink 9 July 1994 + + Copyright (C) 1995 Rutherford Appleton Laboratory + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp -- cgit