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/node56.html | 146 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 src/slalib/sun67.htx/node56.html (limited to 'src/slalib/sun67.htx/node56.html') diff --git a/src/slalib/sun67.htx/node56.html b/src/slalib/sun67.htx/node56.html new file mode 100644 index 0000000..e71b073 --- /dev/null +++ b/src/slalib/sun67.htx/node56.html @@ -0,0 +1,146 @@ + + + + +SLA_DH2E - Az,El to + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_DIMXV - Apply 3D Reverse Rotation +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DFLTIN - Decode a Double Precision Number +

+

+

    +
+SLA_DH2E - Az,El to $h,\delta$

+
+
ACTION: +
Horizon to equatorial coordinates +(double precision). +

CALL: +
CALL sla_DH2E (AZ, EL, PHI, HA, DEC) +

+

+
GIVEN: +
+
+ + + + + + + + + + + + + +
AZDazimuth (radians)
ELDelevation (radians)
PHIDlatitude (radians)
+

+
RETURNED: +
+
+ + + + + + + + + +
HADhour angle (radians)
DECDdeclination (radians)
+

+
NOTES: +
+
1. +
The sign convention for azimuth is north zero, east $+\pi/2$.
2. +
HA is returned in the range $\pm \pi$. Declination is returned +in the range $\pm \pi$.
3. +
The latitude is (in principle) geodetic. In critical + applications, corrections for polar motion should be applied + (see sla_POLMO). +
4. +
In some applications it will be important to specify the + correct type of elevation in order to produce the required + type of $[\,h,\delta\,]$. In particular, it may be important to + distinguish between the elevation as affected by refraction, + which will yield the observed $[\,h,\delta\,]$, and the elevation + in vacuo, which will yield the topocentric + $[\,h,\delta\,]$. If the + effects of diurnal aberration can be neglected, the + topocentric $[\,h,\delta\,]$ may be used as an approximation to the + apparent $[\,h,\delta\,]$.
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. +
+
+ +next + +up + +previous +
+ Next: SLA_DIMXV - Apply 3D Reverse Rotation +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_DFLTIN - Decode a Double Precision Number +

+

+

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