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/node53.html | 145 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 src/slalib/sun67.htx/node53.html (limited to 'src/slalib/sun67.htx/node53.html') diff --git a/src/slalib/sun67.htx/node53.html b/src/slalib/sun67.htx/node53.html new file mode 100644 index 0000000..05a6c56 --- /dev/null +++ b/src/slalib/sun67.htx/node53.html @@ -0,0 +1,145 @@ + + + + +SLA_DE2H - to Az,El + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_DEULER - Euler Angles to Rotation Matrix +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DD2TF - Days to Hour,Min,Sec +

+

+

    +
+SLA_DE2H - $h,\delta$ to Az,El +

+
+
ACTION: +
Equatorial to horizon coordinates +(double precision). +

CALL: +
CALL sla_DE2H (HA, DEC, PHI, AZ, EL) +

+

+
GIVEN: +
+
+ + + + + + + + + + + + + +
HADhour angle (radians)
DECDdeclination (radians)
PHIDlatitude (radians)
+

+
RETURNED: +
+
+ + + + + + + + + +
AZDazimuth (radians)
ELDelevation (radians)
+

+
NOTES: +
+
1. +
Azimuth is returned in the range $0\!-\!2\pi$; north is zero, +and east is $+\pi/2$. Elevation is returned in the range +$\pm \pi$.
2. +
The latitude must be geodetic. In critical applications, + corrections for polar motion should be applied. +
3. +
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 $[\,h,\delta\,]$, and the elevation + in vacuo, which would require the topocentric + $[\,h,\delta\,]$. If the effects of diurnal aberration can be neglected, the + apparent $[\,h,\delta\,]$ may be used instead of the topocentric + $[\,h,\delta\,]$.
4. +
No range checking of arguments is carried out. +
5. +
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. +
+
+ +next + +up + +previous +
+ Next: SLA_DEULER - Euler Angles to Rotation Matrix +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DD2TF - Days to Hour,Min,Sec +

+

+

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