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Last Update: August 17, 2020

Version 2.54 is now available. Addition of Solar Eclipse Path and Libration of the Moon.


This website provides a free program that uses astronomical algorithms to solve basic equations in celestial mechanics. The program simulates the orbital motion of the planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) around the Sun. The planetary motion is solved for any selected day(s) and then the data is put into a convenient set of tables for your observational applications.

The tables of solar system data include:

  • Sun - Rise, Transit, Set Times; Ephemeris; Solar Eclipses
  • Moon - Rise, Transit, Set Times; Ephemeris; Moon Phases; Lunar Eclipses
  • Planets - Rise, Transit, Set Times; Ephemeris; Phenomena; Equinox and Solstice Dates
  • Rationale:
    I have had a strong interest in solar system astronomy for many years, so I decided to develop a Windows based simulation software called Sun Moon Planets. I find this program quite useful for my solar system observations and am providing it free for use to anyone with an interest in astronomy.

    I wish to acknowledge Jean Meeus and his book Astronomical Algorithms, PJ Naughter for his coding insights, also, Oliver Montenbruck and Thomas Pfleger's book Astronomy on the Personal Computer.


    DownloadButton 64

    This program does not require any special installation or registration. It is a simple program written in C++ and uses the Windows api, all compiled into one file. It should run on any 64 Bit Windows (7 or later).


    After you download the file, unzip it and put the application somewhere on your Desktop or in a folder.

    To run the program just click on the application icon (the icon is my picture of the eclipsed Sun from August 21 , 2017).

    Opening Screen

    Typical opening screen of the program.


    Here are a few more screen shots:

    Solar Eclipse Table and Path

    Solar Eclipse Table and Path.


    SkyViewA SkyViewB

    SkyView During Day and Night.


    Ecliptic View - Path of Sun

    Ecliptic View - Path of Sun.


    Lunar Calendar

    Lunar Calendar.




    A PDF version of the Quick Guide is available. Download Quick Guide.

    Using Sun Moon Planets - Orbital Elements is available. Download Using Sun Moon Planets - Orbital Elements.

    Using Sun Moon Planets - Right Ascension and Declination is also available. Download Using Sun Moon Planets - Right Ascension and Declination.


    Contact: I welcome your constructive comments on this program. If you find any errors in the data or if you have suggestions for further development please email them to me at dgarner@astrotables.com.



    Download the Program and Try These Examples to See How You Can Use It.
    1) The opening screen of the program shows the position of the planets at the present date (0 hours UT). Use the menu item Select a Date to change the year to the next year or the previous year. Again note the position of the planets, particularly that Earth is still in the same position and Mars has moved approximately halfway around its orbital path. Try advancing the month and days and note the changing position of the planets. Approximately how long did it take for Mercury and Venus to make a complete orbit around the Sun?

    2) On the opening screen adjust the vertical slider (right-hand side of screen) to about the mid-position. Note all the planets appear to be orbiting in a flat plane. This plane is called the Ecliptic. Click on View and select Ecliptic View. In the dialog box click the check box to show the planets. Note how the planets are all very close to the blue line (Ecliptic). The blue line gives the RA and Dec of any planet, Moon or the Sun at any date. Inside the dialog box adjust the date by increasing the month and clicking the Go button. Note the motions along the Ecliptic of the Sun, Moon and planets.

    3) Click View and select Earth Moon Sun View. Note the position of the Moon with respect to Earth. Click on Select a Date again and advance the days one at a time to 7 days. How far did the Moon go around the Earth? Advance the month by one month. How far did the Earth go around the Sun? How far did the Moon go around the Earth?

    4) Reset the screen to show planets orbiting the Sun. Set the date to March 20 (or March 21 - depending on the year). Click menu item Tables and select Sun Tables. Click the tab Sun Ephemeris and set the date to March 20. In the first row of data (Sun Ephemeris tab) take note of the Date, RA and Dec. The RA of the Sun should be close to 0 (or 24) hours. Look at the relative position of the Sun with respect to the Earth. The Earth should be directly in-line with the Sun and in opposition to the First Point of Aries. Next, find the date when RA of the Sun is equal to 12 hours (in September). Set that date for the main screen and note that Earth will be in conjunction with the First Point of Aries and in-line with the Sun. At RA of the Sun equal to 24 hours, Earth be back where it was on March 20.

    5) Click menu item Tables and select Planet Tables. In the dialog box click the tab Earth Equinox / Solstice Dates. Note the date of the June (Summer) Solstice. Click the screen menu item Date and change the month and day to the date shown in the Planet dialog box. On the main screen you should see the relative position of the Sun and Earth at the Summer Solstice (compared to the direction of the First Point of Aries). Repeat this procedure using the dates in the dialog box to see the position of Earth with respect to the Sun at the Winter Solstice in December.

    6) Click View and select Earth Moon Sun View. Click menu item Tables and select Moon Tables. In the dialog box click the tab Quarterly Phases of the Moon. In the listing find the date of the next New Moon. Click the menu item Date and change the year, month and day to the date shown in the dialog box. Then close the dialog boxes and observe the position of the Earth, Moon and Sun on the screen. The Moon should be in-line (conjunction) with the Sun. Keep in mind that the positions of the Earth and Moon were calculated at 0 hours UT but the time of the New Moon may be a few hours more or less than that. Repeat this procedure to view the position of the Moon at First Quarter, Full Moon and Last Quarter. You can also observe this using the Ecliptic View dialog box. By changing the dates you can observe the position of the Moon in relation to the Sun.

    7) Click View and select Earth Moon Sun View. Click menu item Tables and select Sun Tables. In the dialog box click the tab Solar Eclipse Tables. In the listing find the date of the next Total Solar Eclipse. Click the menu item Date and change the year, month and day to the date shown in the dialog box. Then close the dialog boxes and observe the position of the Earth, Moon and Sun on the screen. The Moon should be in-line between the Sun and Earth. You may also note in the green text on the top left side of the screen that it indicates a New Moon and the Solar Eclipse at a given time UT. Note that on the screen the Moon may not be completely in position since the position of the Earth and Moon were calculated at 0 hours UT and the solar eclipse probably occurs several hours later (solar eclipses don't occur at midnight).

    8) Click View and select Earth Moon Sun View. Click menu item Tables and select Moon Tables. In the dialog box click the tab Lunar Eclipse Tables. In the listing find the date of the next Total Lunar Eclipse. Click the menu item Date and change the year, month and day to the date shown in the dialog box. Then close the dialog boxes and observe the position of the Earth, Moon and Sun on the screen. The Moon should be in opposition to the Sun. You may also note in the green text on the top left side of the screen that it indicates a Full Moon and the Total Lunar Eclipse at a given time UT. Note that on the screen the Moon may not be completely in position since the position of the Earth and Moon were calculated at 0 hours UT and the lunar eclipse may occur a few hours before or after 0 hours UT (midnight).

    9) Click View and de-select Earth Moon Sun View. You should be showing the main screen with all the planets. Click menu item Tables and select Planet Tables. In the dialog box click the tab Planetary Phenomena. From the combo box select the planet Mercury and click the Go button. In the listing find the date of the next Superior Conjunction. Click the menu item Date and change the year, month and day to the date shown in the dialog box. Then close the dialog boxes and observe the position of the Earth, Mercury and the Sun. To improve the view you might move the vertical slider to the bottom and then use the Scale Tool to enlarge the orbits.

    10) On the main screen with all the planets, click menu item Tables and select Planet Tables. In the dialog box click the tab Planetary Phenomena. From the combo box select the planet Mars and click the Go button. In the listing find the date of the next Opposition. Click the menu item Date and change the year, month and day to the date shown in the dialog box. Then close the dialog boxes and observe the position of the Earth, Mars and the Sun. To improve the view you might move the vertical slider to the bottom and then use the Scale Tool to enlarge the orbits. Note the green text on the top left side of the screen - Mars at Opposition. There are many other features in this program for you to discover. Be careful to set the dates on the main screen to the dates obtained in the Sun, Moon, and Planet dialog boxes.

    There are many other features of this program to investigate. I hope that you enjoy them.

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    Donations to help support this website and its maintenance can be made through PayPal and are very much appreciated.



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    This program is copyrighted as of January 1, 2018. It is the property of David Garner. It may be used freely but there are no warranties on this program. The calculated data is reasonably accurate to the best of my knowledge.

    Copyright © 2018, David Garner, www.astrotables.com