The focus of this guide is on software designed to be used in the field of astronomy, including its branches of astrophysics, astrochemistry, astrobiology, physical cosmology, extragalactic astronomy, galactic astronomy, stellar astronomy, solar astronomy, and planetary science.
At one time, astrology was considered to be a branch of astronomy, but astrology is no longer considered a true science, and we list Astrology in the Paranormal categories.
Astronomy is one of the natural sciences and defined as the study of the sun, moon, planets, stars, galaxies, and other non-Earthly bodies and phenomena. In its curriculum for elementary school students, NASA defines astronomy as the study of stars, planets, and space.
Astrophysics is the branch of astronomy that relates to the physical nature of the stars and other celestial bodies, as well as the application of the laws of physics to the interpretation of astronomical observations.
Astrochemistry is the study of the chemical substances and species that may exist in the stars and interstellar space.
Also known as exobiology or xenobiology, astrobiology is the field of astronomy that deals with the search, existence, and nature of extraterrestrial life, which refers to life beyond Earth. Astrobiology encompasses areas of astronomy, biology, and geology.
Physical cosmology is the study of the large-scale structure of the universe, studying the fundamental questions of the formation and evolution of the universe.
The branch of astronomy concerned with objects outside of the Milky Way galaxy is known as extragalactic astronomy. Although at one time, it was believed that the Milky Way galaxy was all there was of the universe, millions of other galaxies have now been photographed and classified by scientists and others, and it is believed that there are about a hundred billion galaxies in the observable universe.
Stellar astronomy is the branch of astronomy that studies regularities in the structure, composition, dynamics, and evolution of stellar systems, as well as the applications of these observations on our stellar system, the Milky Way.
Solar astronomy relates to the study of the Sun and the phenomena that surround it, including the physics, chemistry, meteorology, motion, and evolution of the Sun, as well as its place in the universe.
Planetary science is an interdisciplinary branch of astronomy, involving physics, geology, astronomy, environmental studies, and other fields, that studies the composition of planets, how they operate, and the differences between them.
The chief topic of this guide is the use of software in astronomy and its related fields. The types of software listed here should be those applications used by scientists, not those that are designed to teach astronomy. We have another category for educational software.
Software is used in a variety of ways by astronomers.
Observation planning software is used to answer questions that an astronomer might need to have answered before spending nights on the telescope. During which period of the night will the target be observable? During that time interval, when is a galaxy, star, or solar system best observed? Is there a bright star near my faint target that I can use as a reference point? These questions are answered days or, in some cases, even years ahead of time, and software has been developed, often by astronomers themselves, that can help to answer these questions so that time spent at a telescope is more productive.
This might include airmass plotting tools, target planning applications, ephemeris tools, and software for offset guide star planning.
Software designed for use by astronomers might make use of the Flexible Image Transport System, more commonly referred to by its acronym, FITS. Because it was developed in the 1970s, in the early days of the computer, FITS imposes tedious coding constraints, but it continues to be used.
Data reduction software assists with the steps required to take raw data into data that is suitable for publication. In reference to astronomy, this may involve the removal of bad pixels, and the subtraction of bias, sky, and/or background, as well as flat fielding, balancing the variations in the pixel-to-pixel response of the detector.
Software tools designed for displaying images that were saved in the FITS format, and live images acquired pixel-by-pixel from the detector, would be appropriate for this category.
These are just a few. There are many others, and more will be developed in the future. Any software designed for use in astronomy is appropriate for this category, whether it is free and open-source, proprietary, or commercial. Software designed for astronomy hobbyists may be listed here as well, as significant astronomical discoveries have been made by hobbyists.
 
 
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Available in several languages for Mac and Windows, a fully-functional trial version can be downloaded for evaluation, or purchased online, with options for single-user, site, or educational site licenses. The software is a solar system simulator that calculates the gravitational interactions between all astronomical bodies, allowing for accurate simulation of the motions of asteroids and comets. The program is not restricted to the solar system. Video is available.
http://www.astrograv.co.uk/
Astronomy Online is the result of a project of two people, with some material contributed by friends, classmates, and colleagues. Its software section is generally targeted for the amateur astronomer, recommending and briefly reviewing various software packages, categorized as planetarium software, specialty observing programs, CCD software, robotic software, and other software, and includes applications for Mac, iOS, and Palm PDA.
http://astronomyonline.org/AstronomySoftware.asp
AstroPlanner will operate on Macintosh and Windows machines. It is used to assist in astronomical observation planning, visualization, and logging, as well as aiding in the control of telescopes with computerized go-to mounts or digital setting circle controllers. The requirements for installing the program are given, along with screenshots, user reviews, and a list of catalogs available for use with AstroPlanner. As shareware, a full version may be downloaded, and purchases may be made online.
http://www.astroplanner.net/
A product of Asynx Software, Asynx Planetarium is a free astronomy software program for MS-Windows PCs. The program will advise when planets are visible, for the present, past, and future, and from any location on earth. Viewing locations can be added or edited through its location editor tool, and its interactive star chart allows users to see stars, planets, sun, and moon across the sky. Available in several languages, it may be downloaded from the site.
http://www.asynx-planetarium.com/
Released under the terms of the GNU General Public License, the program can be used with Linux, macOS, and Windows machines. It is designed to enable the user to draw sky charts, making use of the data in many catalogs of stars and nebulae, and the positions of planets, asteroids, and comets are also shown, its purpose is to prepare different sky maps for a particular observation. Documentation is published to the site, along with screenshots, and development news.
https://ap-i.net/skychart/
Also known as C2A, the planetarium software is designed to allow the user to build detailed views of stellar fields. Available only in a Windows version, it is intended to serve professional and amateur astronomers, helping them to prepare observations on small fields as well as astronomers and photometry works. It also serves as general-purpose planetarium software, with a variety of functions. It may be downloaded and used for free. A DOS version, which can be run on a Mac, is available.
http://www.astrosurf.com/c2a/english/
Available from the National Aeronautics and Space Administration, Goddard Space Flight Center's Science and Exploration department, FTOOLS is a general package of software to manipulate FITS files. Instructions for downloading, installing, and setting up the FTOOLS are given, along with known issues, a tutorial, FAQ, and sub-packages. Guidelines for developing a new FTOOLS package for a mission or instrument are given, including a developer's guide and other documentation.
https://heasarc.gsfc.nasa.gov/docs/software/ftools/
Free and open-source, Gpredict is licensed under the GNU General Public License, available as a source package as well as precompiled binaries through third parties. The application is a real-time satellite tracking and orbit prediction program capable of tracking a large number of satellites, displaying their positions and other data in lists, tables, maps, and polar plots. It can also predict the time of future passes for a satellite. Features, screenshots, and user support options are given.
http://gpredict.oz9aec.net/
LunarPhase is a software utility for Windows that provides a range of information on the Moon and, to a lesser degree, the Sun, graphically displaying the current phase of the moon in real-time, using the user’s geographic location, time zone, and daylight saving’s time for its calculations. Its features are listed on the site, along with an introduction, screenshots, and other information. Available for purchase, LunarPhase Pro offers additional features, such as an interactive moon atlas.
https://www.nightskyobserver.com/LunarPhase/
Featuring astrophotography and astronomy on the Apple Macintosh, the site features several image taken with Mac applications and processed on an Apple computer, including a blog, as well as sections on macOS software designed for use in the astronomy and astrophotography field, particularly hobbyists, and another section for iPhone and iPad astronomy software, made for the iOS operating system, categorized by purpose, with links to the applications website.
https://www.macobservatory.com/
The Mars Orbiter Laser Altimeter (MOLA) is an instrument on the Mars Global Surveyor (MGS), a spacecraft that was launched in November of 1996, orbiting the planet and mapping it for four and a half years. The Mars MOLA Viewer can be used to download its data and render it as a 3D landscape, allowing the viewer to “fly” through it. Its requirements are stated, along with instructions for running the program, which is available as free and open-source (GPL) software.
http://cgibin.starpower.net/mmacdonald31/demo3d/mars/
The MarsClock is a clock for the planet Mars. Designed for engineers, scientists, and anyone else working on Mars surface missions, the MarsClock is a port of Mars24, developed entirely on a Palm using OnBoardC, and it runs on the PalmOS operating system, requiring MathLib to operate. The error between MarsClock and the JPL MER timesheets is less than one minute for the nominal mission duration. Available under the GNU General Public License, the software and source is free.
http://marsclock.sourceforge.net/
Released in 2001, Moon Calculator is a DOS program that provides information on the position, age, phase, orientation, appearance, and visibility of the moon for any given date, time, and location on earth, along with the Julian Day number, magnetic declination, time, and direction of moonrise and moonset, the interval between sunset and moonset, interval between sunrise and moonrise, and other data. Examples of program output are displayed, and it may be downloaded from the site.
http://www.mooncalc.moonsighting.org.uk/
Designed to be used for fun, education, and science, Nightfall can produce animated views of eclipsing binary stars, calculate synthetic lightcurves and radial velocity curves, and even determine the best-fit model for a given set of observational data of an eclipsing binary star system. Available in English and German, it comes with a user guide and a set of observational data for several eclipsing binary star systems. An overview of the program, requirements, and instructions are included.
http://www.hs.uni-hamburg.de/DE/Ins/Per/Wichmann/Nightfall.html
With editions for Windows and Macintosh platforms, Starry Night is professional astronomy telescope control software for the Mac or PC. Offering packages for beginners, serious amateur astronomers, and two options for professional astronomers, modules include universal search, high-performance graphics, an extragalactic 3D database, new and updating space missions, 3D suns, and updated Messier catalog, 3D exoplanets, H-R diagrams, an ephemeris generator, graph tools, and others.
https://www.starrynight.com/
Available for Linux, Mac, Windows, and the Web, Stellarium is a free and open-source planetarium for the computer, showing a realistic sky in 3D, like what one might see with the naked eye, binoculars, or a telescope. A scripting feature is included. System requirements, a list of features, developer credits, development notes, and documentation are provided, along with a user guide, developer documentation, a wiki, a FAQ, and a discussion forum.
https://stellarium.org/