AutoPA scripts initial upload

Python scripts that calculate polar misalignment values based on three RA/DEC inputs. It determines the alt/az of the current alignment, calculates the delta compared to true polar alignment, then issues LX200 commands to the OAT to correct.

Author: CTetford

Software/Addons/AutoPA/altaz.py

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+#!/usr/bin/env python3
+import sys
+import serial
+import re
+
+def altaz(axis, errorvalue, serialport):
+	if not re.match(r"^[-+]?([0-9]*\.[0-9]+|[0-9]+)$", errorvalue):
+		print("Error value not valid")
+		return
+		
+	errorvalue = float(errorvalue)
+	if axis.lower() == "alt":
+		print(f"Adjusting Altitude by {errorvalue:.4f} arcminutes.")
+		commandToSend = f":MAL{errorvalue}#"
+	elif axis.lower() == "az":
+		print(f"Adjusting Azimuth by {errorvalue:.4f} arcminutes.")
+		commandToSend = f":MAZ{errorvalue}#"
+	else:
+		print("Axis input not correct")
+		return
+
+	#print(command) #For debugging
+
+	ser = serial.Serial(serialport, 57600, timeout = 1)
+	#commandToSend = ':Sr16:00:00#:MS#'
+	ser.write(str(commandToSend).encode())
+	return
+	
+if len(sys.argv) != 4:
+	print("Incorrect number of parameters")
+	sys.exit()
+		
+axis = sys.argv[1]
+errorvalue = sys.argv[2]
+serialport = sys.argv[3]
+
+altaz(axis, errorvalue, serialport)
+

Software/Addons/AutoPA/polaralign.py

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+#!/usr/bin/env python3
+import math
+from astropy.coordinates import SkyCoord, EarthLocation, AltAz, Angle
+from astropy import units as u
+from astropy.time import Time
+from astropy.utils import iers
+import sys, subprocess
+
+def polarcalc(mylat, mylong, myelev, time, p1RA, p1DEC, p2RA, p2DEC, p3RA, p3DEC):
+	#iers.conf.auto_download = False
+	#iers.conf.auto_max_age = None
+	
+	#Create time object based on given time
+	observing_time = Time('2020-08-10 3:00:05')
+
+	#Create location object based on lat/long/elev
+	observing_location = EarthLocation(lat=mylat*u.deg, lon=mylong*u.deg, height=177*u.m)
+
+	#Create coordinate objects for each point
+	p1 = SkyCoord(p1RA, p1DEC, unit='deg')
+	p2 = SkyCoord(p2RA, p2DEC, unit='deg')
+	p3 = SkyCoord(p3RA, p3DEC, unit='deg')
+	p1X = (90 - p1.dec.degree) * math.cos(p1.ra.radian)
+	p1Y = (90 - p1.dec.degree) * math.sin(p1.ra.radian)
+	p2X = (90 - p2.dec.degree) * math.cos(p2.ra.radian)
+	p2Y = (90 - p2.dec.degree) * math.sin(p2.ra.radian)
+	p3X = (90 - p3.dec.degree) * math.cos(p3.ra.radian)
+	p3Y = (90 - p3.dec.degree) * math.sin(p3.ra.radian)
+
+	#Calculate center of circle using three points in the complex plane. DEC is treated as unitless for the purposes of the calculation.
+	x, y, z = complex(p1X,p1Y), complex(p2X,p2Y), complex(p3X,p3Y)
+	w = z-x
+	w /= y-x
+	c = (x-y)*(w-abs(w)**2)/2j/w.imag-x
+	resultX = -c.real
+	resultY = c.imag
+
+	#Convert X/Y values of circle into RA/DEC
+	resultDEC = (90 - math.sqrt(resultX**2 + resultY**2))
+	resultRA = math.atan2(resultY, resultX)*360 / (2*math.pi)
+	if resultRA < 0:
+			resultRA = (180-abs(resultRA))+180
+
+	#Create coordinate object for current alignment offset
+	offset = SkyCoord(resultRA, resultDEC, frame='icrs', unit='deg')
+	print(f"Current alignment in RA/DEC: {offset.ra.to_string(u.hour, precision=2)}/{offset.dec.to_string(u.deg, precision=2)}.")
+
+	#Create coordinate object for pole
+	pole = SkyCoord(0, 90, frame='icrs', unit='deg')
+	
+	#Create coordinate object for pole
+	poleAzAlt = pole.transform_to(AltAz(obstime=observing_time,location=observing_location))
+	print(f"True polar alignment in Az./Alt.: 0h00m00s/{Angle(mylat*u.degree).to_string(u.degree, sep=('d', 'm', 's'), precision=2)}.")
+
+	#Transform current alignment to Alt/Az coordinate system
+	#offsetAzAlt = offset.transform_to(AltAz(obstime=observing_time,location=observing_location, temperature=25*u.deg_C, pressure=101325*u.Pa, relative_humidity=0.5))
+	offsetAzAlt = offset.transform_to(AltAz(obstime=observing_time,location=observing_location))
+	print(f"Current alignment in Az./Alt.: {offsetAzAlt.az.to_string(u.hour, precision=2)}/{offsetAzAlt.alt.to_string(u.deg, precision=2)}.")
+
+	#Calculate offset deltas from pole
+	if offsetAzAlt.az.deg < 180:
+		errorAz = -offsetAzAlt.az.deg*60
+	else:
+		errorAz = (360-offsetAzAlt.az.deg)*60
+	print(f"Azimuth error correction is: {errorAz:.4f} arcminutes.")
+	errorAlt = (mylat - offsetAzAlt.alt.deg)*60
+	print(f"Altitude error correction is: {errorAlt:.4f} arcminutes.")
+	
+	return errorAz, errorAlt
+
+#Latitude in degrees
+mylat = float(sys.argv[1])
+
+#Longitude in degrees
+mylong = float(sys.argv[2])
+
+#Elevation in meters
+myelev = sys.argv[3]
+
+#YYYY-MM-DD HH:MM:SS format
+time = sys.argv[4]
+
+#All RA/DEC values must be in compatible format to Astropy.coordinates library.
+#Preferrably degrees, but 00h00m00.0s and 00d00m00.0s should also work
+p1RA = sys.argv[5]
+p1DEC = sys.argv[6]
+p2RA = sys.argv[7]
+p2DEC = sys.argv[8]
+p3RA = sys.argv[9]
+p3DEC = sys.argv[10]
+
+serialport = '/dev/ttyACM0'
+
+result = polarcalc(mylat, mylong, myelev, time, p1RA, p1DEC, p2RA, p2DEC, p3RA, p3DEC)
+
+#Verify error correction can be handled by AutoPA hardware (assuming it is in home/centered position)
+moveAz = "N"
+if abs(result[0]) > 192:
+	moveAz = input("Azimuth error may be out of bounds of hardware capabilities if not in home position. Continue? (Y/N): ") 
+else:
+	moveAz = "Y"
+if moveAz.upper() == "Y":
+	#Call process to move azimuth using elevated privileges  to override any existing serial connection
+	subprocess.call(['sudo', './altaz.py', "az", str(result[0]), serialport])
+
+moveAlt = "N"
+if result[1] > 168:
+	moveAz = input("Altitude error may be out of bounds of hardware capabilities if not in home position. Continue? (Y/N): ")
+elif result[1] > 432:
+	moveAz = input("Altitude error may be out of bounds of hardware capabilities if not in home position. Continue? (Y/N): ")
+else:
+	moveAlt = "Y"
+if moveAlt.upper() == "Y":
+	#Call process to move altitude using elevated privileges to override any existing serial connection
+	subprocess.call(['sudo', './altaz.py', "alt", str(result[1]), serialport])