Naledi Nova Telescope Navigator

This is my implementation of the Raspberry Pi Planet Finder project originally created by Snowbiscuit. This project creates a DIY digital navigation tool for stargazing, allowing you to automatically orient a telescope toward a chosen planet using real-time data and stepper motors.

• Naledi means "star" in Sesotho.

Important Note

The planet finder can only find objects catalogued in the JPL Horizons on-line solar system data and ephemeris computation service. So this can only find objects in the Solar System. Deep sky objects are not included.

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Demo

Link to video demo

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Images

Naledi Nova Front (with T-Cobbler)	Naledi Nova Inside (with T-Cobbler)

Naledi Nova Front	Telescope Not In Use

Telescope In Use 1 (Moon viewing)	Telescope In Use 2 (Moon viewing)

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Project Overview

This project is a DIY tool for amateur astronomers, designed to make finding planets in the night sky easier. It automates the process of aligning a telescope with a selected planet using data from NASA’s JPL Horizons API, which provides real-time ephemeris data for celestial objects.

Key Features

1. User Input: Use buttons to select different planets from a list.
2. Data Retrieval: Get up-to-date azimuth and elevation angles for each planet from JPL Horizons.
3. Motorized Movement: Stepper motors adjust the telescope’s azimuth (horizontal) and elevation (vertical) angles to point at the selected planet.
4. User Feedback: The 16x2 LCD displays the currently selected planet and its position data for easy navigation.

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What This Code Base Covers

This Python code runs on the Raspberry Pi to handle:

1. Initialization: Configures GPIO pins for motors and buttons, sets up the LCD, and prepares stepper motors for movement.
2. Event Handlers: Responds to button presses to select planets, align the telescope, or adjust settings.
3. Data Fetching: Uses Astroquery to access JPL Horizons data and fetch azimuth/elevation coordinates of planets.
4. Motor Control: Provides functions to move the telescope using stepper motors, with specific sequences for accurate positioning.
5. LCD Display: Shows the current planet selection and position coordinates, providing feedback for navigation.

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Bill of Materials

Here are the hardware components and tools required to build this project, following the exact parts as recommended in the original Raspberry Pi Planet Finder tutorial:

Hardware Components

1. Telescope: Zhumell Z114 - 114 mm (4.5 inch) Tabletop Dobsonian
2. Single-board Computer (SBC): Raspberry Pi 3B
3. LCD Display: 16x2 I2C LCD Display, preferably with a PCF8574 I2C expander (Model: YwRobot 1602)
4. Stepper Motors:
   • 28BYJ-48 5V Stepper Motors (x2, one for each axis)
   • ULN2003 Stepper Motor Driver Boards (x2, one for each motor)
5. Buttons: 3x Tactile push buttons (for select, increment, and decrement functions)
6. Breadboard and Jumper Wires: To connect components to the Raspberry Pi GPIO
7. Power Supply: Reliable 5V power supply, preferably with a capacity to handle the Raspberry Pi and both motors simultaneously

Tools

1. Screwdrivers: For assembly and adjustment
2. Soldering Kit: For any necessary soldering (depending on motor connections)
3. Multimeter: For testing connections and voltage if needed

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Technology Stack

• Programming Language: Python 3.7.3

• Libraries:

  • astroquery==0.4.7: To fetch astronomical data from JPL Horizons API
  • RPi.GPIO==0.7.0: For controlling GPIO pins on the Raspberry Pi
  • RPLCD==1.3.1: To control the 16x2 LCD screen

• Additional Software:

  • I2C Configuration: Ensure I2C is enabled on the Raspberry Pi for LCD communication

• Raspberry Pi operating system version preconfigured on Astroberry Image: OS info based on command cat /etc/os-release

  PRETTY_NAME="Raspbian GNU/Linux 10 (buster)" NAME="Raspbian GNU/Linux" VERSION_ID="10" VERSION="10 (buster)" VERSION_CODENAME=buster ID=raspbian ID_LIKE=debian HOME_URL="http://www.raspbian.org/" SUPPORT_URL="http://www.raspbian.org/RaspbianForums" BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

  OS bit info based on command getconf LONG_BIT 32

  OS cpu info based on command uname -m armv7l

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Tutorial Used

The project was inspired by Raspberry Pi Planet Finder on Instructables. This tutorial is a comprehensive guide on building a sky navigation system for telescopes, especially useful for hobbyist astronomers.

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How to Build

1. Hardware Setup

• Connect the 16x2 I2C LCD display to the Raspberry Pi via I2C.
• Attach the 28BYJ-48 stepper motors to control azimuth and elevation angles of the telescope.
• Connect tactile buttons to the Raspberry Pi GPIO pins to handle user inputs.

2. Software Setup

1. Enable I2C on the Raspberry Pi: Run sudo raspi-config and enable I2C under "Interface Options."
2. Clone the Repository: Download this project to your Raspberry Pi.
3. Install Python 3.7.3.
4. Clone this repository: git clone https://github.com/Kgotso-Koete/naledi-nova.
5. Move into naledi-nova folder: cd naledi-nova.
6. Install virtualenv.
7. Create a new virtualenv called "env-naledi-nova": python3 -m venv env-naledi-nova.
8. Set the local virtualenv to "env-naledi-nova ": source env-naledi-nova/bin/activate. If all went well then your command line prompt should now start with (env-naledi-nova). To deactivate navigate to the project directory and run the command deactivate
9. Install the required packages: pip3 install -r requirements.txt 10.Set up a background worker: run crontab -e add the line@reboot /home/kgotso-koete/Documents/Projects/naledi-nova/env-naledi-nova/bin/python /home/kgotso-koete/Documents/Projects/naledi-nova/naledi-nova.py test if the virtual environment will run with /home/kgotso-koete/Documents/Projects/naledi-nova/env-naledi-nova/bin/python /home/kgotso-koete/Documents/Projects/naledi-nova/naledi-nova.py

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Acknowledgements

Special thanks to Snowbiscuit for creating a really cool astronomy project tutorial. I got to explore both astronomy and my Raspberry Pi with this experiment.

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Experiment outcomes

It was a good experiment because I got to work on a project that involved both the Raspberry Pi and astronomy:

Notes

1. Raspberry Pi's are expensive in my part of the world. It would be better to wire everything to an extension board so that the Pi is easy to swap out and use in another project.
2. I was planning on adding a laser diode (one that is legal and acceptable to use) on the telescope finder/pointer but could not find one that could cast a visible ray into the sky.
3. JPL Horizons on-line solar system data and ephemeris API only covers objects in the Solar System. Deep sky objects are not included. Big objects on our solar system are easier to find with a mini-dobsonian telescope compared to deep sky objects.
4. Having to first point north and then navigate north and then point to an object makes this not as reliable. I can't figure out if and how to take the magnetic declination/variation from Johannesburg into account. There must be another way, a dummy proof way.

So it's not worth developing this project further other than wiring everything to the extension board, I will look into Digital Setting Circles instead.

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License

The codebase is MIT licensed unless otherwise specified.

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To be modified further, by Kgotso Koete
Johannesburg, South Africa