This is a python 3.11+ library that can be used to communicate and control Celestron NexStar telescope devices. The library does not have support for GPS units or CGE mounts (but could easily be added).

This library was created as an exercise to see if I could image the ISS with my telescope.

To see the latest features and updates, please see the CHANGELOG. If you would like to request a feature or report a bug, please submit directly on the issues tracker on GitHub.

To install this package, you can use pip:

pip install nexstar-control

or with Poetry

poetry add nexstar-control

This package has the following dependencies:

• pyserial
• tzdata

This package was created using the documentation found on the NexStar Resrouce Site.

For a more complete example of how to use this library, see the sample.py file in the root of this repository.

import datetime
from zoneinfo import ZoneInfo

from nexstar_control.device import NexStarHandControl, TrackingMode, LatitudeDMS, LongitudeDMS

hc = NexStarHandControl("COM1")
if not hc.is_connected():
    print("Failed to connect to device")
    exit(1)

# get the current position of the telescope in ra/dec or alt/az coordinates
ra, dec = hc.get_position_ra_dec()
alt, az = hc.get_position_alt_az()

# issue go to commands in ra/dec coordinates or alt/az coordinates
hc.goto_ra_dec(180, 0)
hc.goto_alt_az(90, 0)

# turn the telescope tracking mode off when doing slewing, but save the current mode to restore later
current_tracking_mode = hc.get_tracking_mode()
hc.set_tracking_mode(TrackingMode.OFF)

# slew the telescope at fixed rates (where negative values indicate the opposite direction)
hc.slew_fixed(9, -9)

# slew the telescope at variable rates (where negative values indicate the opposite direction)
hc.slew_variable(15000, -15000)

# restore the tracking mode
hc.set_tracking_mode(current_tracking_mode)

# set the location and time of the telescope
hc.set_location(lat=LatitudeDMS.from_decimal(49.2849), lng=LongitudeDMS.from_decimal(-122.8678))
dt = datetime.datetime.now(tz=ZoneInfo("America/Vancouver"))
hc.set_time(dt)

This package usings Poetry for dependency management and packaging. To install the development dependencies, run the following command:

poetry install

This package uses ruff for code formatting and linting. To format the code, run the following command:

poetry run ruff format

To lint the code, run the following command:

poetry run ruff check --fix

This package uses pre-commit to run the formatting and linting checks before committing. To install the pre-commit hooks, run the following command:

poetry run pre-commit install

This package uses pytest for testing. To run the tests, run the following command:

poetry run pytest

This project is licensed under the MIT License - see the LICENSE file for details.

• NexStar Resource Site
  • website hosted by Michael Swanson
• Celestron