From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/sun67.htx/node65.html | 117 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 src/slalib/sun67.htx/node65.html (limited to 'src/slalib/sun67.htx/node65.html') diff --git a/src/slalib/sun67.htx/node65.html b/src/slalib/sun67.htx/node65.html new file mode 100644 index 0000000..de89921 --- /dev/null +++ b/src/slalib/sun67.htx/node65.html @@ -0,0 +1,117 @@ + + + + +SLA_DPAV - Position-Angle Between Two Directions + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_DR2AF - Radians to Deg,Min,Sec,Frac +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DMXV - Apply 3D Rotation +

+

+

SLA_DPAV - Position-Angle Between Two Directions +   +

+
+
ACTION: +
Returns the bearing (position angle) of one celestial +direction with respect to another (double precision). +

CALL: +
D = sla_DPAV (V1, V2) +

+

+
GIVEN: +
+
+ + + + + + + + + +
V1D(3)direction cosines of one point
V2D(3)directions cosines of the other point
+

+
RETURNED: +
+
+ + + + + +
sla_DPAVDposition-angle of 2nd point with respect to 1st
+

+
NOTES: +
+
1. +
The coordinate frames correspond to $[\,\alpha,\delta\,]$,$[\lambda,\phi]$ etc.. +
2. +
The result is the bearing (position angle), in radians, + of point V2 as seen + from point V1. It is in the range $\pm \pi$. The sense + is such that if V2 + is a small distance due east of V1 the result + is about $+\pi/2$. Zero is returned + if the two points are coincident. +
3. +
The routine sla_DBEAR performs an equivalent function except + that the points are specified in the form of spherical coordinates. +
+
+ +next + +up + +previous +
+ Next: SLA_DR2AF - Radians to Deg,Min,Sec,Frac +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DMXV - Apply 3D Rotation +

+

+

+SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk +
+ + -- cgit