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-rwxr-xr-xastro/radec.py57
1 files changed, 57 insertions, 0 deletions
diff --git a/astro/radec.py b/astro/radec.py
new file mode 100755
index 0000000..4cc2b71
--- /dev/null
+++ b/astro/radec.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2017 Aaron LI <aly@aaronly.me>
+# MIT License
+#
+
+"""
+Convert among various (R.A., Dec.) coordinate formats.
+"""
+
+import argparse
+
+from astropy import units as au
+from astropy.coordinates import Angle
+
+
+def parse_coord(c):
+ if len(c) == 6:
+ # h m s d m s
+ ra = Angle((float(c[0]), float(c[1]), float(c[2])), unit=au.hourangle)
+ dec = Angle((float(c[3]), float(c[4]), float(c[5])), unit=au.deg)
+ elif len(c) == 2:
+ ra = Angle(float(c[0]), unit=au.deg)
+ dec = Angle(float(c[1]), unit=au.deg)
+ else:
+ raise ValueError("invalid coordinate: {0}".format(c))
+ return (ra, dec)
+
+
+def main():
+ parser = argparse.ArgumentParser(
+ description="Convert among multiple coordinate formats")
+ parser.add_argument("coord", nargs="+")
+ args = parser.parse_args()
+
+ ra, dec = parse_coord(args.coord)
+ info = (
+ "%-14s %-14s\n" % ("R.A.", "Dec.") +
+ "%s--%s\n" % ("-"*14, "-"*14) +
+ "%-14.3f %-+14.3f\n" % (ra.deg, dec.deg) +
+ "%-14s %-14s\n" % (
+ ra.to_string(unit=au.hourangle, precision=4),
+ dec.to_string(unit=au.deg, alwayssign=True, precision=3)) +
+ "%-14s %-14s\n" % (
+ ra.to_string(unit=au.hourangle, sep=":", precision=4),
+ dec.to_string(unit=au.deg, alwayssign=True,
+ sep=":", precision=3)) +
+ "%-14s %-14s\n" % (
+ ra.to_string(unit=au.hourangle, sep=" ", precision=4),
+ dec.to_string(unit=au.deg, alwayssign=True,
+ sep=" ", precision=3))
+ )
+ print(info)
+
+
+if __name__ == "__main__":
+ main()