From 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 Mon Sep 17 00:00:00 2001
From: Joe Hunkeler <jhunkeler@gmail.com>
Date: Tue, 11 Aug 2015 16:51:37 -0400
Subject: Repatch (from linux) of OSX IRAF

---
 noao/astutil/asttools/astcoord.x | 56 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 noao/astutil/asttools/astcoord.x

(limited to 'noao/astutil/asttools/astcoord.x')

diff --git a/noao/astutil/asttools/astcoord.x b/noao/astutil/asttools/astcoord.x
new file mode 100644
index 00000000..07a01ee3
--- /dev/null
+++ b/noao/astutil/asttools/astcoord.x
@@ -0,0 +1,56 @@
+# AST_COORD -- Convert spherical coordinates to new system.
+#
+# This procedure converts the longitude-latitude coordinates (a1, b1)
+# of a point on a sphere into corresponding coordinates (a2, b2) in a
+# different coordinate system that is specified by the coordinates of its
+# origin (ao, bo).  The range of a2 will be from -pi to pi.
+
+procedure ast_coord (ao, bo, ap, bp, a1, b1, a2, b2)
+
+double	ao, bo		# Origin of new coordinates (radians)
+double	ap, bp		# Pole of new coordinates (radians)
+double	a1, b1		# Coordinates to be converted (radians)
+double	a2, b2		# Converted coordinates (radians)
+
+double	sao, cao, sbo, cbo, sbp, cbp
+double	x, y, z, xp, yp, zp, temp
+
+begin
+	x = cos (a1) * cos (b1)
+	y = sin (a1) * cos (b1)
+	z = sin (b1)
+	xp = cos (ap) * cos (bp)
+	yp = sin (ap) * cos (bp)
+	zp = sin (bp)
+
+	# Rotate the origin about z.
+	sao = sin (ao)
+	cao = cos (ao)
+	sbo = sin (bo)
+	cbo = cos (bo)
+	temp = -xp * sao + yp * cao
+	xp = xp * cao + yp * sao
+	yp = temp
+	temp = -x * sao + y * cao
+	x = x * cao + y * sao
+	y = temp
+
+	# Rotate the origin about y.
+	temp = -xp * sbo + zp * cbo
+	xp = xp * cbo + zp * sbo
+	zp = temp
+	temp = -x * sbo + z * cbo
+	x = x * cbo + z * sbo
+	z = temp
+
+	# Rotate pole around x.
+	sbp = zp
+	cbp = yp
+	temp = y * cbp + z * sbp
+	y = y * sbp - z * cbp
+	z = temp
+
+	# Final angular coordinates.
+	a2 = atan2 (y, x)
+	b2 = asin (z)
+end
-- 
cgit