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Diffstat (limited to 'math/slalib/doc/dpav.hlp')
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diff --git a/math/slalib/doc/dpav.hlp b/math/slalib/doc/dpav.hlp new file mode 100644 index 00000000..d0111a2d --- /dev/null +++ b/math/slalib/doc/dpav.hlp @@ -0,0 +1,38 @@ +.help dpav Jun99 "Slalib Package" +.nf + + DOUBLE PRECISION FUNCTION slDPAV ( V1, V2 ) + + - - - - - + D P A V + - - - - - + + Position angle of one celestial direction with respect to another. + + (double precision) + + Given: + V1 d(3) direction cosines of one point + V2 d(3) direction cosines of the other point + + (The coordinate frames correspond to RA,Dec, Long,Lat etc.) + + The result is the bearing (position angle), in radians, of point + V2 with respect to point V1. It is in the range +/- pi. The + sense is such that if V2 is a small distance east of V1, the + bearing is about +pi/2. Zero is returned if the two points + are coincident. + + V1 and V2 need not be unit vectors. + + The routine slDBER performs an equivalent function except + that the points are specified in the form of spherical + coordinates. + + Patrick Wallace Starlink 13 July 1997 + + Copyright (C) 1997 Rutherford Appleton Laboratory + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp |