mirror of
https://github.com/cosinekitty/astronomy.git
synced 2026-01-03 04:59:51 -05:00
5eca7d7760
Updated CodeQL config to ignore source templates, because they are not syntactically valid source code. Ignore other stuff that is irrelevant to published code quality. Made various fixes based on helpful CodeQL analysis.
76 lines
2.2 KiB
Python
Executable File
76 lines
2.2 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
#
|
|
# galactic.py - by Don Cross - 2021-06-14
|
|
#
|
|
# Example Python program for Astronomy Engine:
|
|
# https://github.com/cosinekitty/astronomy
|
|
#
|
|
# Demo of converting galactic coordinates to horizontal coordinates.
|
|
#
|
|
|
|
import sys
|
|
from astronomy import *
|
|
|
|
UsageText = r'''
|
|
USAGE: galactic olat olon glat glon [yyyy-mm-ddThh:mm:ssZ]
|
|
|
|
where
|
|
|
|
olat = observer's latitude on the Earth
|
|
olon = observer's longitude on the Earth
|
|
glat = IAU 1958 galatic latitude of the target
|
|
glon = IAU 1958 galatic longitude of the target
|
|
yyyy-mm-ddThh:mm:ssZ = optional UTC date/time
|
|
|
|
Given the galactic coordinates of a point source in the sky,
|
|
this program calculates horizontal aiming coordinates for an
|
|
observer on or near the Earth's surface.
|
|
|
|
If the date/time is given on the command line, it is used.
|
|
Otherwise, the computer's current date/time is used.
|
|
'''
|
|
|
|
|
|
def GalacticToHorizontal(time, observer, glat, glon):
|
|
# Calculate a matrix that converts galactic coordinates
|
|
# to J2000 equatorial coordinates.
|
|
rot = Rotation_GAL_EQJ()
|
|
|
|
# Adjust the rotation matrix to convert galactic to horizontal.
|
|
adjust_rot = Rotation_EQJ_HOR(time, observer)
|
|
rot = CombineRotation(rot, adjust_rot)
|
|
|
|
# Convert the galactic coordinates from angles to a unit vector.
|
|
gsphere = Spherical(glat, glon, 1.0)
|
|
gvec = VectorFromSphere(gsphere, time)
|
|
|
|
# Use the rotation matrix to convert the galactic vector to a horizontal vector.
|
|
hvec = RotateVector(rot, gvec)
|
|
|
|
# Convert the horizontal vector back to angular coordinates.
|
|
# Assume this is a radio source (not optical), do not correct for refraction.
|
|
hsphere = HorizonFromVector(hvec, Refraction.Airless)
|
|
return hsphere.lat, hsphere.lon
|
|
|
|
|
|
if __name__ == '__main__':
|
|
if len(sys.argv) not in [5, 6]:
|
|
print(UsageText)
|
|
sys.exit(1)
|
|
|
|
olat = float(sys.argv[1])
|
|
olon = float(sys.argv[2])
|
|
observer = Observer(olat, olon)
|
|
|
|
glat = float(sys.argv[3])
|
|
glon = float(sys.argv[4])
|
|
|
|
if len(sys.argv) > 5:
|
|
time = Time.Parse(sys.argv[5])
|
|
else:
|
|
time = Time.Now()
|
|
|
|
altitude, azimuth = GalacticToHorizontal(time, observer, glat, glon)
|
|
print('altitude = {:10.3f}, azimuth = {:10.3f}'.format(altitude, azimuth))
|
|
sys.exit(0)
|