From 9b7f99bbd0eca0e611601dd936c1f7948f8cd58a Mon Sep 17 00:00:00 2001
From: Aaron LI <aly@aaronly.me>
Date: Wed, 19 Jul 2017 16:34:40 +0800
Subject: Use [arcsec] as the unit for pixel size and resolution

Signed-off-by: Aaron LI <aly@aaronly.me>
---
 fg21sim/utils/units.py |  7 +++++++
 fg21sim/utils/wcs.py   | 14 +++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

(limited to 'fg21sim/utils')

diff --git a/fg21sim/utils/units.py b/fg21sim/utils/units.py
index aea0f92..bb8f670 100644
--- a/fg21sim/utils/units.py
+++ b/fg21sim/utils/units.py
@@ -50,6 +50,13 @@ class UnitConversions:
     keV2erg = au.keV.to(au.erg)
     # Angle
     rad2deg = au.rad.to(au.deg)
+    deg2rad = au.deg.to(au.rad)
+    arcmin2deg = au.arcmin.to(au.deg)
+    deg2arcmin = au.deg.to(au.arcmin)
+    arcsec2deg = au.arcsec.to(au.deg)
+    deg2arcsec = au.deg.to(au.arcsec)
+    arcmin2arcsec = au.arcmin.to(au.arcsec)
+    arcsec2arcmin = au.arcsec.to(au.arcmin)
 
 
 class Constants:
diff --git a/fg21sim/utils/wcs.py b/fg21sim/utils/wcs.py
index b4a9ed1..3cb76b9 100644
--- a/fg21sim/utils/wcs.py
+++ b/fg21sim/utils/wcs.py
@@ -8,6 +8,8 @@ Create WCS for sky projection.
 import numpy as np
 from astropy.wcs import WCS
 
+from .units import UnitConversions as AUC
+
 
 def make_wcs(center, size, pixelsize, frame="ICRS", projection="TAN"):
     """
@@ -16,11 +18,13 @@ def make_wcs(center, size, pixelsize, frame="ICRS", projection="TAN"):
     Parameters
     ----------
     center : (xcenter, ycenter) float tuple
-        The equatorial/galactic coordinate of the sky/image center [ deg ].
+        The equatorial/galactic coordinate of the sky/image center.
+        Unit: [deg]
     size : (xsize, ysize) int tuple
         The size (width, height) of the sky/image.
     pixelsize : float
-        The pixel size of the sky/image [ arcmin ]
+        The pixel size of the sky/image.
+        Unit: [arcsec]
     frame : str, "ICRS" or "Galactic"
         The coordinate frame, only one of ``ICRS`` or ``Galactic``.
     projection : str, "TAN" or "CAR"
@@ -31,10 +35,14 @@ def make_wcs(center, size, pixelsize, frame="ICRS", projection="TAN"):
     -------
     w : `~astropy.wcs.WCS`
         Created WCS header/object
+
+    TODO/XXX
+    ---------
+    To support other projections, e.g., ``SIN`` (common in radio astronomy).
     """
     xcenter, ycenter = center  # [ deg ]
     xsize, ysize = size
-    delt = pixelsize / 60.0  # [ deg ]
+    delt = pixelsize * AUC.arcsec2deg  # [ deg ]
     if projection.upper() not in ["TAN", "CAR"]:
         raise ValueError("unsupported projection: " % projection)
     if frame.upper() == "ICRS":
-- 
cgit v1.2.2