Jul 20, 2023

Scientific-grade astronomical computations for Python

PyEphem provides scientific-grade astronomical computations for the Python programming language. Given a date and location on the Earth’s surface, it can compute the positions of the Sun and Moon, of the planets and their moons, and of any asteroids, comets, or earth satellites whose orbital elements the user can provide. Additional functions are provided to compute the angular separation between two objects in the sky, to determine the constellation in which an object lies, and to find the times at which an object rises, transits, and sets on a particular day.

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For all astronomy lovers out there, FreeBSD has a fantastic port known as “pyephem”. It falls under the category of astro, and it gives both professional astronomers and hobbyists high-precision computations. This article aims to guide you on how to use the PyEphem software effectively and leverage its benefits.

About PyEphem

PyEphem is a Python astronomy library for performing high-precision astronomy computations. The library uses algorithms and mathematical models identical to those used in the XEphem astronomy application. By using PyEphem, you can easily calculate times of rise and setting for any celestial body, determine at what angle a body reaches culmination, and even find when the next full moon will be.

Installing pyephem

Before you start working with PyEphem, you need to make sure you have Python installed on your FreeBSD system. This could be done through the lang/python port. The link to our page on Python is [here]https//

To install PyEphem, you can use the FreeBSD Ports collection. Here is a simple guide to achieve this

# Change directory to the pyephem port
$ cd /usr/ports/astro/pyephem 

# Install the port
$ make install clean

After installing, you use PyEphem through Python.

Using PyEphem

Let’s start with a simple example of calculating when the International Space Station ISS will pass over a particular location.

First, you need to know the ‘Two-Line Element Set’ TLE of the ISS. This data can be obtained from various online resources. Here is an example of a TLE for the ISS

1 25544U 98067A   21275.58693519  .00001303  00000-0  26834-4 0  9991
2 25544  51.6456  53.7978 0008140 307.7287  52.2955 15.48934355298547

Next, create a Python script

import ephem

# Define the TLE elements for ISS Zarya
lines = [
    'ISS ZARYA',
    '1 25544U 98067A   21275.58693519  .00001303  00000-0  26834-4 0  9991',
    '2 25544  51.6456  53.7978 0008140 307.7287  52.2955 15.48934355298547'

# Create a PyEphem 'Body'
iss = ephem.readtle*lines

# Define the observer's location
obs = ephem.Observer = '51.5072'    # Latitude for London, UK
obs.long = '-0.1276'   # Longitude for London, UK

# Get the next pass for this observer
next_pass = obs.next_passiss

for attr in next_pass

This script will print the next five attributes associated with the ISS’s coming pass rise time, rise azimuth, maximum altitude time, maximum altitude, set time, set azimuth.

You can calculate similar data for any celestial body given you know the necessary details required by PyEphem.

Understanding the Benefits of Using PyEphem

The PyEphem library allows you to perform complex astronomical calculations with relative ease. It is designed to handle precision up to the milliarcsecond level. Here are its primary benefits

  1. Simple Installation PyEphem runs on the Python programming language, which is easy to install and widely used.

  2. High Precision It provides high-precision astronomy computations using advanced algorithms and models.

  3. Versatile It’s not only for professional astronomers; even astronomy enthusiasts can use it for various purposes like stargazing, eclipses, or for satellite tracking.

  4. Fruitful Community As with many FreeBSD ports, PyEphem has an active community of users and developers. This ensures that the platform is continually updated and provides support when encountering problems.

To further elevate the functionality of your FreeBSD system, consider exploring and integrating additional ports relevant to your tasks. For instance, if you’re working in IT security, we highly recommend the security/nmap port, a powerful tool for network discovery and security auditing. Find out more about it [here]https//

FreeBSD, with ports like PyEphem, continues to provide solutions for a broad range of professional and hobbyist needs. The flexibility and robustness of these ports not only provide users with precise solutions but also provide a learning experience, especially for those interested in operating systems and software development.

Embrace the stars and harness the power of high-precision astronomical computation with PyEphem!

Checkout these related ports:
  • Xworld - Earth as seen from the direction of the sun
  • Xtide - Harmonic tide clock and tide predictor
  • Xplanet - Draw pictures of the earth textured by an image
  • Xphoon - Set the root window to the moon in its current phase
  • Xmoontool - Version of John Walker's classical moontool for X11/Motif
  • Xephem - Interactive astronomical ephemeris program
  • Xeartk - Small demo for tkgeomap
  • Xearth - Set the root window to the image of earth
  • Wmsun - Dockapp that displays the rise and set times of the Sun
  • Wmspaceweather - DockApp that shows the weather at geosynchronous orbit
  • Wmsolar - Dockapp that displays the Solar System viewed from the top
  • Wmmoonclock - Displays the phase of the moon, plus orbital data
  • Wmjupiter - Dockapp that displays information on Jupiter
  • Wmglobe - Neat xearth-like WindowMaker dockapp
  • Weather - Utility to provide current weather conditions and forecasts