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#!/usr/bin/env python
"""TCP/IP server which listens for Meade LX200 style serial commands.
Intended to mimick a SkyFi (serial to TCP/IP bridge) and compatible
Meade telescope normally controlled via a serial cable. In theory
this could be modified to listen to an actual serial port too...
The intended goal is that celestial/planetarium software like the
SkySafari applications can talk to this server as if it was an off
the shelf Meade LX200 compatible "Go To" telescope, when in fact
it is a DIY intrumented telescope or simulation.
See http://astrobeano.blogspot.co.uk/2014/01/instrumented-telescope-with-raspberry.html
Testing with Sky Safari Plus v4.0, with the telescope usually setup as:
Scope Type: Meade LX-200 GPS
Mount Type: Equatorial Push-To (or any push to setting)
Auto-Detect SkyFi: Off
IP Address: That of the computer running this script (default 10.0.0.1)
Port Number: 4030 (default)
Set Time & Location: On (default is off)
Readout Rate: 4 per second (default)
Save Log File: Off (default)
With this, the "Connect/Disconnect" button works fine, once connected
the scope queries the position using the :GR# and :GD# commands.
The "Goto" button is disabled (when configured as a Push-To telecope).
The "Align" button gives an are you sure prompt with the currently
selected objects name (e.g. a star), and then sends its position
using the Sr and Sd commands, followed by the :CM# command.
The "Lock/Unlock" button controls if SkySafari automatically pans
the display to keep the reported telescope direction centered.
If configured as a Goto telescope, additional left/right and up/down
buttons appear on screen (which send East/West, North/South movement
commands. Also, a slew rate slider control appears. Depending on which
model telescope was selected, this may give four rates via the
RC/RG/RM/RS commands, or Sw commands (in the range 2 to 8).
If SkySafari's "Set Time & Location" feature is selected, it will
send commands St and Sg (for the location) then SG, SL, SC to set
the time and date. If using "Meade LX-200 Classic" this imposes
a 15s delay, using a newer model like the "Meade LX-200 GPS" there
is no noticeable delay on connection.
Additional limited testing also done with the Celestron NexStar
protocol, although SkySafari 4 does not seem to use its built in
commands for setting the date/time or location, nor the synching
commands for alignment.
"""
#More references on Alt/Az horizontal coordinates to equatorial:
#http://pythonhosted.org/Astropysics/coremods/obstools.html#astropysics.obstools.Site
#https://github.com/eteq/astropysics/issues/21
#https://github.com/astropy/astropy-api/pull/6
#http://infohost.nmt.edu/tcc/help/lang/python/examples/sidereal/ims/
import socket
import os
import sys
import commands
try:
import configparser
except ImportError:
import ConfigParser as configparser
import time
import datetime
from math import pi, sin, cos, asin, acos, atan2, modf
#TODO - Try astropy if I can get it to compile on Mac OS X...
from astropysics import coords
from astropysics import obstools
#Local import
from gy80 import GY80
config_file = "telescope_server.ini"
if not os.path.isfile(config_file):
print("Using default settings")
h = open("telescope_server.ini", "w")
h.write("[server]\nname=10.0.0.1\nport=4030\n")
#Default to Greenwich as the site
h.write("[site]\nlatitude=+51d28m38s\nlongitude=0\n")
#Default to no correction of the angles
h.write("[offsets]\nazimuth=0\naltitude=0\n")
h.close()
print("Connecting to sensors...")
imu = GY80()
print("Connected to GY-80 sensor")
print("Opening network port...")
config = configparser.ConfigParser()
config.read("telescope_server.ini")
server_name = config.get("server", "name") #e.g. 10.0.0.1
server_port = config.getint("server", "port") #e.g. 4030
#server_name = socket.gethostbyname(socket.gethostname())
#if server_name.startswith("127.0."): #e.g. 127.0.0.1
# #This works on Linux but not on Mac OS X or Windows:
# server_name = commands.getoutput("/sbin/ifconfig").split("\n")[1].split()[1][5:]
##server_name = "10.0.0.1" #Override for wifi access
#server_port = 4030 #Default port used by SkySafari
#If default to low precision, SkySafari turns it on anyway:
high_precision = True
#Default to Greenwich, GMT - Latitude 51deg 28' 38'' N, Longitude zero
local_site = obstools.Site(coords.AngularCoordinate(config.get("site", "latitude")),
coords.AngularCoordinate(config.get("site", "longitude")),
tz=0)
#Rather than messing with the system clock, will store any difference
#between the local computer's date/time and any date/time set by the
#client (which should match any location set by the client).
local_time_offset = 0
#This will probably best be inferred by calibration...
#For Greenwich, magnetic north is estimated to be 2 deg 40 min west
#of grid north at Greenwich in July 2013.
#http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
#local_site_magnetic_offset = -2.67 * pi / 180.0
#These will come from sensor information... storing them in radians
local_alt = 85 * pi / 180.0
local_az = 30 * pi / 180.0
offset_alt = config.getfloat("offsets", "altitude")
offset_az = config.getfloat("offsets", "azimuth")
#These will come from the client... store them in radians
target_ra = 0.0
target_dec = 0.0
#Turn on for lots of logging...
debug = False
def save_config():
global condig, config_file
with open(config_file, "w") as handle:
config.write(handle)
def _check_close(a, b, error=0.0001):
if isinstance(a, (tuple, list)):
assert isinstance(b, (tuple, list))
assert len(a) == len(b)
for a1, b1 in zip(a, b):
diff = abs(a1-b1)
if diff > error:
raise ValueError("%s vs %s, for %s vs %s difference %s > %s"
% (a, b, a1, b1, diff, error))
return
diff = abs(a-b)
if diff > error:
raise ValueError("%s vs %s, difference %s > %s"
% (a, b, diff, error))
def update_alt_az():
global imu, offset_alt, offset_az, local_alt, local_az
yaw, pitch, roll = imu.current_orientation_euler_angles_hybrid()
#yaw, pitch, roll = imu.current_orientation_euler_angles_mag_acc_only()
#Yaw is measured from (magnetic) North,
#Azimuth is measure from true North:
local_az = (offset_az + yaw) % (2*pi)
#Pitch is measured downwards (using airplane style NED system)
#Altitude is measured upwards
local_alt = (offset_alt + pitch) % (2*pi)
#We don't care about the roll for the Meade LX200 protocol.
def site_time_gmt_as_epoch():
global local_time_offset
return time.time() + local_time_offset
def site_time_gmt_as_datetime():
return datetime.datetime.fromtimestamp(site_time_gmt_as_epoch())
def site_time_local_as_datetime():
global local_site
return site_time_gmt_as_datetime() - datetime.timedelta(hours=local_site.tz)
def debug_time():
global local_site
if local_site.tz:
sys.stderr.write("Effective site date/time is %s (local time), %s (GMT/UTC)\n"
% (site_time_local_as_datetime(), site_time_gmt_as_datetime()))
else:
sys.stderr.write("Effective site date/time is %s (local/GMT/UTC)\n"
% site_time_gmt_as_datetime())
def greenwich_sidereal_time_in_radians():
"""Calculate using GMT (according to client's time settings)."""
#Function astropysics.obstools.epoch_to_jd wants a decimal year as input
#Function astropysics.obstools.calendar_to_jd can take a datetime object
gmt_jd = obstools.calendar_to_jd(site_time_gmt_as_datetime())
#Convert from hours to radians... 24hr = 2*pi
return coords.greenwich_sidereal_time(gmt_jd) * pi / 12
def alt_az_to_equatorial(alt, az, gst=None):
global local_site #and time offset used too
if gst is None:
gst = greenwich_sidereal_time_in_radians()
lat = local_site.latitude.r
#Calculate these once only for speed
sin_lat = sin(lat)
cos_lat = cos(lat)
sin_alt = sin(alt)
cos_alt = cos(alt)
sin_az = sin(az)
cos_az = cos(az)
dec = asin(sin_alt*sin_lat + cos_alt*cos_lat*cos_az)
hours_in_rad = acos((sin_alt - sin_lat*sin(dec)) / (cos_lat*cos(dec)))
if sin_az > 0.0:
hours_in_rad = 2*pi - hours_in_rad
ra = gst - local_site.longitude.r - hours_in_rad
return ra % (pi*2), dec
def equatorial_to_alt_az(ra, dec, gst=None):
global local_site #and time offset used too
if gst is None:
gst = greenwich_sidereal_time_in_radians()
lat = local_site.latitude.r
#Calculate these once only for speed
sin_lat = sin(lat)
cos_lat = cos(lat)
sin_dec = sin(dec)
cos_dec = cos(dec)
h = gst - local_site.longitude.r - ra
sin_h = sin(h)
cos_h = cos(h)
alt = asin(sin_lat*sin_dec + cos_lat*cos_dec*cos_h)
az = atan2(-cos_dec*sin_h, cos_lat*sin_dec - sin_lat*cos_dec*cos_h)
return alt, az % (2*pi)
#This test implicitly assumes time between two calculations not significant:
_check_close((1.84096, 0.3984), alt_az_to_equatorial(*equatorial_to_alt_az(1.84096, 0.3984)))
#_check_close(parse_hhmm("07:01:55"), 1.84096) # RA
#_check_close(parse_sddmm("+22*49:43"), 0.3984) # Dec
#This ensures identical time stamp used:
gst = greenwich_sidereal_time_in_radians()
for ra in [0.1, 1, 2, 3, pi, 4, 5, 6, 1.99*pi]:
for dec in [-0.49*pi, -1.1, -1, 0, 0.001, 1.55, 0.49*pi]:
alt, az = equatorial_to_alt_az(ra, dec, gst)
_check_close((ra, dec), alt_az_to_equatorial(alt, az, gst))
del gst, ra, dec
# ====================
# Meade LX200 Protocol
# ====================
def meade_lx200_cmd_CM_sync():
"""For the :CM# command, Synchronizes the telescope's position with the currently selected database object's coordinates.
Returns:
LX200's - a "#" terminated string with the name of the object that was synced.
Autostars & LX200GPS - At static string: "M31 EX GAL MAG 3.5 SZ178.0'#"
"""
#SkySafari's "align" command sends this after a pair of :Sr# and :Sd# commands.
global offset_alt, offset_az
global local_alt, local_az, target_alt, target_dec
sys.stderr.write("Resetting from current position Alt %s (%0.5f radians), Az %s (%0.5f radians)\n" %
(radians_to_sddmmss(local_alt), local_alt, radians_to_hhmmss(local_az), local_az))
sys.stderr.write("New target position RA %s (%0.5f radians), Dec %s (%0.5f radians)\n" %
(radians_to_hhmmss(target_ra), target_ra, radians_to_sddmmss(target_dec), target_dec))
target_alt, target_az = equatorial_to_alt_az(target_ra, target_dec)
offset_alt += (target_alt - local_alt)
offset_az += (target_az - local_az)
offset_alt %= 2*pi
offset_az %= 2*pi
config.set("offsets", "altitude", offset_alt)
config.set("offsets", "azimuth", offset_az)
save_config()
update_alt_az()
sys.stderr.write("Revised current position Alt %s (%0.5f radians), Az %s (%0.5f radians)\n" %
(radians_to_sddmmss(local_alt), local_alt, radians_to_hhmmss(local_az), local_az))
return "M31 EX GAL MAG 3.5 SZ178.0'"
def meade_lx200_cmd_MS_move_to_target():
"""For the :MS# command, Slew to Target Object
Returns:
0 - Slew is Possible
1<string># - Object Below Horizon w/string message
2<string># - Object Below Higher w/string message
"""
#SkySafari's "goto" command sends this after a pair of :Sr# and :Sd# commands.
#For return code 1 and 2 the error message is not shown, simply that the
#target is below the horizon (1) or out of reach of the mount (2).
global target_ra, target_dec
if target_dec < 0:
return "1Target declination negative"
else:
return "2Sorry, no goto"
def parse_hhmm(value):
"""Turn string HH:MM.T or HH:MM:SS into radians."""
parts = value.split(":")
if len(parts) == 2:
h = int(parts[0])
m = float(parts[1])
s = 0
else:
h, m, s = [int(v) for v in parts]
# 12 hours = 43200 seconds = pi radians
return (h*3600 + m*60 + s) * pi / 43200
_check_close(parse_hhmm("00:02.3"), 0.010035643198967393)
_check_close(parse_hhmm("00:02.4"), 0.010471975511965976)
_check_close(parse_hhmm("00:02:17"), 0.009962921146800963)
_check_close(parse_hhmm("00:02:18"), 0.010035643198967393)
_check_close(parse_hhmm("12:00:00"), pi)
def parse_sddmm(value):
"""Turn string sDD*MM or sDD*MM:SS into radians."""
if value[3] != "*":
if len(value) == 9 and value[3] == chr(223) and value[6] == ":":
# Stellarium's variant in v0.12.4, since fixed:
# https://bugs.launchpad.net/stellarium/+bug/1272960
# http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/6529
value = value.replace(chr(223), "*")
else:
raise ValueError("Bad format %r" % value)
if value[0] == "+":
sign = +1
elif value[0] == "-":
sign = -1
else:
raise ValueError("Bad sign in %r" % value)
deg = int(value[1:3])
if len(value) == 6:
arc_minutes = int(value[4:6])
arc_seconds = 0
elif len(value) != 9 or value[6] != ":":
raise ValueError("Bad format %r" % value)
else:
arc_minutes = int(value[4:6])
arc_seconds = int(value[7:9])
return sign * (deg + arc_minutes/60.0 + arc_seconds/3600.0) * pi / 180.0
_check_close(parse_sddmm("+00*01"), 0.000290888208666)
_check_close(parse_sddmm("+00*01:00"), 0.000290888208666)
_check_close(parse_sddmm("+57*17:45"), 1.0)
_check_close(parse_sddmm("+57*18"), 1.0)
_check_close(parse_hhmm("07:01:55"), 1.84096) # RA
_check_close(parse_sddmm("+22*49:43"), 0.3984) # Dec
def radians_to_hms(angle):
fraction, hours = modf(angle * 12 / pi)
fraction, minutes = modf(fraction * 60)
return hours, minutes, fraction * 60
_check_close(radians_to_hms(0.01), (0, 2, 17.50987083139755))
_check_close(radians_to_hms(6.28), (23.0, 59.0, 16.198882117679716))
def radians_to_hhmmss(angle):
while angle < 0.0:
sys.stderr.write("Warning, radians_to_hhmmss called with %0.2f\n" % angle)
angle += 2*pi
h, m, s = radians_to_hms(angle)
return "%02i:%02i:%02i#" % (h, m, round(s))
def radians_to_hhmmt(angle):
while angle < 0.0:
sys.stderr.write("Warning, radians_to_hhmmt called with %0.2f\n" % angle)
angle += 2*pi
h, m, s = radians_to_hms(angle)
return "%02i:%02i.%01i#" % (h, m, round(s / 6))
def radians_to_sddmm(angle):
"""Signed degrees, arc-minutes as sDD*MM# for protocol."""
if angle < 0.0:
sign = "-"
angle = abs(angle)
else:
sign = "+"
fraction, degrees = modf(angle * 180 / pi)
return "%s%02i*%02i#" % (sign, degrees, round(fraction * 60.0))
def radians_to_sddmmss(angle):
"""Signed degrees, arc-minutes, arc-seconds as sDD*MM:SS# for protocol."""
if angle < 0.0:
sign = "-"
angle = abs(angle)
else:
sign = "+"
fraction, degrees = modf(angle * 180 / pi)
fraction, arcminutes = modf(fraction * 60.0)
return "%s%02i*%02i:%02i#" % (sign, degrees, arcminutes, round(fraction * 60.0))
for r in [0.000290888208666, 1, -0.49*pi, -1.55, 0, 0.01, 0.1, 0.5*pi]:
#Testing RA from -pi/2 to pi/2
assert -0.5*pi <= r <= 0.5*pi, r
_check_close(parse_sddmm(radians_to_sddmm(r).rstrip("#")), r, 0.0002)
_check_close(parse_sddmm(radians_to_sddmmss(r).rstrip("#")), r)
for r in [0, 0.01, 0.1, pi, 2*pi]:
#Testing dec from 0 to 2*pi
assert 0 <= r <= 2*pi, r
_check_close(parse_hhmm(radians_to_hhmmt(r).rstrip("#")), r)
_check_close(parse_hhmm(radians_to_hhmmss(r).rstrip("#")), r)
def meade_lx200_cmd_GR_get_ra():
"""For the :GR# command, Get Telescope RA
Returns: HH:MM.T# or HH:MM:SS#
Depending which precision is set for the telescope
"""
#TODO - Since :GR# and :GD# commands normally in pairs, cache this?
update_alt_az()
ra, dec = alt_az_to_equatorial(local_alt, local_az)
if high_precision:
return radians_to_hhmmss(ra)
else:
#The .T is for tenths of a minute, see e.g.
#http://www.manualslib.com/manual/295083/Meade-Lx200.html?page=55
return radians_to_hhmmt(ra)
def meade_lx200_cmd_GD_get_dec():
"""For the :GD# command, Get Telescope Declination.
Returns: sDD*MM# or sDD*MM'SS#
Depending upon the current precision setting for the telescope.
"""
update_alt_az()
ra, dec = alt_az_to_equatorial(local_alt, local_az)
if debug:
sys.stderr.write("RA %s (%0.5f radians), dec %s (%0.5f radians)\n"
% (radians_to_hhmmss(ra), ra, radians_to_sddmmss(dec), dec))
if high_precision:
return radians_to_sddmmss(dec)
else:
return radians_to_sddmm(dec)
def meade_lx200_cmd_Sr_set_target_ra(value):
"""For the commands :SrHH:MM.T# or :SrHH:MM:SS#
Set target object RA to HH:MM.T or HH:MM:SS depending on the current precision setting.
Returns: 0 - Invalid, 1 - Valid
Stellarium breaks the specification and sends things like ':Sr 20:39:38#'
with an extra space.
"""
global target_ra
try:
target_ra = parse_hhmm(value.strip()) # Remove any space added by Stellarium
# The extra space sent by Stellarium v0.12.4 has been fixed:
# https://bugs.launchpad.net/stellarium/+bug/1272960
sys.stderr.write("Parsed right-ascension :Sr%s# command as %0.5f radians\n" % (value, target_ra))
return "1"
except Exception as err:
sys.stderr.write("Error parsing right-ascension :Sr%s# command: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_Sd_set_target_de(value):
"""For the command :SdsDD*MM# or :SdsDD*MM:SS#
Set target object declination to sDD*MM or sDD*MM:SS depending on the current precision setting
Returns: 1 - Dec Accepted, 0 - Dec invalid
Stellarium breaks this specification and sends things like ':Sd +15\xdf54:44#'
with an extra space, and the wrong characters. Apparently chr(223) is the
degrees symbol on some character sets.
"""
global target_dec
try:
target_dec = parse_sddmm(value.strip()) # Remove any space added by Stellarium
# The extra space sent by Stellarium v0.12.4 has been fixed:
# https://bugs.launchpad.net/stellarium/+bug/1272960
sys.stderr.write("Parsed declination :Sd%s# command as %0.5f radians\n" % (value, target_dec))
return "1"
except Exception as err:
sys.stderr.write("Error parsing declination :Sd%s# command: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_U_precision_toggle():
"""For the :U# command, Toggle between low/hi precision positions
Low - RA displays and messages HH:MM.T sDD*MM
High - Dec/Az/El displays and messages HH:MM:SS sDD*MM:SS
Returns Nothing
"""
global high_precision
high_precision = not high_precision
if high_precision:
sys.stderr.write("Toggled high precision, now ON.\n")
else:
sys.stderr.write("Toggled high precision, now OFF.\n")
return None
def meade_lx200_cmd_St_set_latitude(value):
"""For the :StsDD*MM# command, Sets the current site latitdue to sDD*MM
Returns: 0 - Invalid, 1 - Valid
"""
#Expect this to be followed by an Sg command to set the longitude...
global local_site, config
try:
value = value.replace("*", "d")
local_site.latitude = coords.AngularCoordinate(value)
#That worked, should be safe to save the value to disk later...
config.set("site", "latitude", value)
return "1"
except Exception as err:
sys.stderr.write("Error with :St%s# latitude: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_Sg_set_longitude(value):
"""For the :SgDDD*MM# command, Set current site longitude to DDD*MM
Returns: 0 - Invalid, 1 - Valid
"""
#Expected immediately after the set latitude command
#e.g. :St+56*29# then :Sg003*08'#
global local_site, config
try:
value = value.replace("*", "d")
local_site.longitude = coords.AngularCoordinate(value)
sys.stderr.write("Local site now latitude %0.3fd, longitude %0.3fd\n"
% (local_site.latitude.d, local_site.longitude.d))
#That worked, should be safe to save the value to disk:
config.set("site", "longitude", value)
save_config()
return "1"
except Exception as err:
sys.stderr.write("Error with :Sg%s# longitude: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_SG_set_local_timezone(value):
"""For the :SGsHH.H# command, Set the number of hours added to local time to yield UTC
Returns: 0 - Invalid, 1 - Valid
"""
#Expected immediately after the set latitude and longitude commands
#Seems the decimal is optional, e.g. :SG-00#
global local_site
try:
local_site.tz = float(value) # Can in theory be partial hour, so not int
sys.stderr.write("Local site timezone now %s\n" % local_site.tz)
return "1"
except Exception as err:
sys.stderr.write("Error with :SG%s# time zone: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_SL_set_local_time(value):
"""For the :SLHH:MM:SS# command, Set the local Time
Returns: 0 - Invalid, 1 - Valid
"""
global local_time_offset
local = time.time() + local_time_offset
#e.g. :SL00:10:48#
#Expect to be followed by an SC command to set the date.
try:
hh, mm, ss = (int(v) for v in value.split(":"))
if not (0 <= hh <= 24):
raise ValueError("Bad hour")
if not (0 <= mm <= 59):
raise ValueError("Bad minutes")
if not (0 <= ss <= 59):
raise ValueError("Bad seconds")
desired_seconds_since_midnight = 60*60*(hh + local_site.tz) + 60*mm + ss
t = time.gmtime(local)
current_seconds_since_midnight = 60*60*t.tm_hour + 60*t.tm_min + t.tm_sec
new_offset = desired_seconds_since_midnight - current_seconds_since_midnight
local_time_offset += new_offset
sys.stderr.write("Requested site time %i:%02i:%02i (TZ %s), new offset %is, total offset %is\n"
% (hh, mm, ss, local_site.tz, new_offset, local_time_offset))
debug_time()
return "1"
except ValueError as err:
sys.stderr.write("Error with :SL%s# time setting: %s\n" % (value, err))
return "0"
def meade_lx200_cmd_SC_set_local_date(value):
"""For the :SCMM/DD/YY# command, Change Handbox Date to MM/DD/YY
Returns: <D><string>
D = '0' if the date is invalid. The string is the null string.
D = '1' for valid dates and the string is
'Updating Planetary Data# #',
Note: For LX200GPS/RCX400/Autostar II this is the UTC data!
"""
#Expected immediately after an SL command setting the time.
#
#Exact list of values from http://www.dv-fansler.com/FTP%20Files/Astronomy/LX200%20Hand%20Controller%20Communications.pdf
#return "1Updating planetary data. #%s#" % (" "*32)
#
#This seems to work but SkySafari takes a while to finish
#if setup as a Meade LX200 Classic - much faster on other
#models.
#
#Idea is to calculate any difference between the computer's
#date (e.g. 1 Jan 1980 if the Raspberry Pi booted offline)
#and the client's date in days (using the datetime module),
#and add this to our offset (converting it into seconds).
#
global local_time_offset
#TODO - Test this in non-GMT/UTC other time zones, esp near midnight
current = datetime.date.fromtimestamp(time.time() + local_time_offset)
try:
wanted = datetime.date.fromtimestamp(time.mktime(time.strptime(value, "%m/%d/%y")))
days = (wanted - current).days
local_time_offset += days * 24 * 60 * 60 # 86400 seconds in a day
sys.stderr.write("Requested site date %s (MM/DD/YY) gives offset of %i days\n" % (value, days))
debug_time()
return "1Updating Planetary Data#%s#" % (" "*30)
except ValueError as err:
sys.stderr.write("Error with :SC%s# date setting: %s\n" % (value, err))
return "0"
def return_one(value=None):
"""Dummy command implementation returning value 1."""
return "1"
def return_none(value=None):
"""Dummy command implementation returning nothing."""
return None
# TODO - Can SkySafari show focus control buttons?
# Would be very cool to connect my motorised focuser to this...
#
# :F+# move in - returns nothing
# :F-# move out - returns nothing
# :FQ# halt Focuser Motion - returns: nothing
# :FF# Set Focus speed to fastest - Returns: Nothing
# :FS# Set Focus speed to slowest - Returns: Nothing
# :F<n># set focuser speed to <n> where <n> is 1..4 - Returns: Nothing
# ==========================
# Celestron NexStar Protocol
# ==========================
def nexstar_cmd_V_version():
"""NexStar command V, version query, returns v1.2"""
return chr(1) + chr(2) + "#"
def nexstar_cmd_E_get_ra_dec():
"""Nexstar command E, get RA/Dec.
Returns integers in hex, fraction of 65536.
"""
update_alt_az()
ra, dec = alt_az_to_equatorial(local_alt, local_az)
#Convert from radians to fraction of 65536
ra = int((65536*ra) / (2*pi))
dec = int((65536*dec) / (2*pi))
return "%04X,%04X#" % (ra, dec)
def nexstar_cmd_e_get_ra_dec_precise():
"""Nexstar command e, get precise RA/Dec.
Returns integers in hex, fraction of 4294967296.
"""
update_alt_az()
ra, dec = alt_az_to_equatorial(local_alt, local_az)
#Convert from radians to fraction of 4294967296
ra = int((4294967296*ra) / (2*pi))
dec = int((4294967296*dec) / (2*pi))
return "%08X,%08X#"% (ra, dec)
def nexstar_cmd_R_goto_ra_dec(value):
"""Nexstar command R, goto RA/Dec
e.g R34AB,12CE
"""
global target_ra, target_dec
target_ra, target_dec = (int(v,16)*2*pi/65536 for v in value.split(","))
return "#"
def nexstar_cmd_r_goto_ra_dec_precise(value):
"""Nexstar command r, goto RA/Dec
e.g. r34AB0500,12CE0500
"""
global target_ra, target_dec
target_ra, target_dec = (int(v,16)*2*pi/4294967296 for v in value.split(","))
return "#"
def nexstar_cmd_M_cancel_goto():
"""Nextstar command M, cancel goto (stop moving)"""
return "#"
def nexstar_cmd_P_passthrough(value):
"""Nexstar command P, pass-though to motor, GPS, etc.
Used for the slew commands (which we don't support).
"""
return "ERROR#"
# ================
# Main Server Code
# ================
command_map = {
#Meade LX200 commands:
":CM": meade_lx200_cmd_CM_sync,
":GD": meade_lx200_cmd_GD_get_dec,
":GR": meade_lx200_cmd_GR_get_ra,
":Me": return_none, #start moving East
":Mn": return_none, #start moving North
":Ms": return_none, #start moving South
":Mw": return_none, #start moving West
":MS": meade_lx200_cmd_MS_move_to_target,
":Q": return_none, #abort all current slewing
":Qe": return_none, #abort slew East
":Qn": return_none, #abort slew North
":Qs": return_none, #abort slew South
":Qw": return_none, #abort slew West
":RC": return_none, #set slew rate to centering (2nd slowest)
":RG": return_none, #set slew rate to guiding (slowest)
":RM": return_none, #set slew rate to find (2nd fastest)
":RS": return_none, #set Slew rate to max (fastest)
":Sd": meade_lx200_cmd_Sd_set_target_de,
":Sr": meade_lx200_cmd_Sr_set_target_ra,
":St": meade_lx200_cmd_St_set_latitude,
":Sg": meade_lx200_cmd_Sg_set_longitude,
":Sw": return_one, #set max slew rate
":SG": meade_lx200_cmd_SG_set_local_timezone,
":SL": meade_lx200_cmd_SL_set_local_time,
":SC": meade_lx200_cmd_SC_set_local_date,
":U": meade_lx200_cmd_U_precision_toggle,
#Celestron NexStar Communication Protocol
"V": nexstar_cmd_V_version,
"E": nexstar_cmd_E_get_ra_dec,
"e": nexstar_cmd_e_get_ra_dec_precise,
"R": nexstar_cmd_R_goto_ra_dec,
"r": nexstar_cmd_r_goto_ra_dec_precise,
"M": nexstar_cmd_M_cancel_goto,
"P": nexstar_cmd_P_passthrough,
}
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_address = (server_name, server_port)
sys.stderr.write("Starting up on %s port %s\n" % server_address)
sock.bind(server_address)
sock.listen(1)
while True:
# SkySafari v4.0.1 continously opens and closed the connection,
# while Stellarium via socat opens it and keeps it open using:
# $ ./socat GOPEN:/dev/ptyp0,ignoreeof TCP:raspberrypi8:4030
# (probably socat which is maintaining the link)
#sys.stdout.write("waiting for a connection\n")
connection, client_address = sock.accept()
data = ""
try:
#sys.stdout.write("Client connected: %s, %s\n" % client_address)
while True:
data += connection.recv(16)
if not data:
imu.update()
break
if debug:
sys.stdout.write("Processing %r\n" % data)
#For stacked commands like ":RS#:GD#",
#but also lone NexStar ones like "e"
while data:
while data[0:1] == "#":
#Stellarium seems to send '#:GR#' and '#:GD#'
#(perhaps to explicitly close and prior command?)
#sys.stderr.write("Problem in data: %r - dropping leading #\n" % data)
data = data[1:]
if not data:
break
if "#" in data:
raw_cmd = data[:data.index("#")]
#sys.stderr.write("%r --> %r as command\n" % (data, raw_cmd))
data = data[len(raw_cmd)+1:]
cmd, value = raw_cmd[:3], raw_cmd[3:]
else:
#This will break on complex NexStar commands,
#but don't care - Meade LX200 is the prority.
raw_cmd = data
cmd = raw_cmd[:3]
value = raw_cmd[3:]
data = ""
if not cmd:
sys.stderr.write("Eh? No command?\n")
elif cmd in command_map:
if value:
if debug:
sys.stdout.write("Command %r, argument %r\n" % (cmd, value))
resp = command_map[cmd](value)
else:
resp = command_map[cmd]()
if resp:
if debug:
sys.stdout.write("Command %r, sending %r\n" % (cmd, resp))
connection.sendall(resp)
else:
if debug:
sys.stdout.write("Command %r, no response\n" % cmd)
else:
sys.stderr.write("Unknown command %r, from %r (data %r)\n" % (cmd, raw_cmd, data))
finally:
connection.close()