What is an orrery?
An orrery is a model of the solar system that shows the positions of celestial bodies like the planets, the moon and our sun.
How I made my dining table orrery
Materials:
Cloth/ backdrop for your orrery (can be anything you already own and is free)
Objects to represent the celestial bodies, this could also be anything you already own and is free, think rocks, trinkets, or your own hand made creations like ceramic or wood carvings. You will assign meaning to these objects to represent the moon, sun and planets
I recommend for beginners to start with just the sun and the moon. You can always add in planets as you progress. (My favorite planet to track is Jupiter, it is the brightest planet when it appears in the night sky)
For your backdrop, you will mentally divide this into the 12 constellations that fall on the ecliptic plane (similar to the way a clock is divided in 12). For the purposes of this orrery I have chosen to omit the constellation Ophiuchus, which falls between Scorpious and Sagittarius.
The 12 o’clock (north) will be Pisces, 3 o’clock (east) Gemini, 6 o’clock (south) Virgo, and 9 o’clock (west) Sagittarius. Fill in the remaining 8 constellations according to their order (see the diagram “Table Set Up” in this post for guidance). We start with Pisces at the top because it has historically been considered the 12th and final zodiac constellation.
Next, place each celestial body in its position for that day. To make sure your placement stays accurate day to day use the online tool found here on the Sky & Telescope website. Position Earth at the center of the backdrop.
I chose to put the Earth at the center for this orrery because my main use for this tool is to visualize where everything is in our night sky in relation to Earth. This positioning assists with my telescope viewing and shows me what planets are visible in the night sky, at dawn, or dusk.
The moon will be your most constant change day to day. It is the satellite that revolves around our Earth and completes a cycle around the orrery every 28 days. The sun will move one constellation over once a month completing its cycle around the orrery in a year.
On the days of a full moon the sun and the moon will be seen placed opposite each other. Conversely days of a new moon they will be seen placed together.
When planets are opposite to the sun they are most visible in the night sky. The closer they are trailing behind the sun clockwise the later at night / early morning they begin to appear in the sky. When their placement appears near front of the sun they will remain out of site to our naked eye in the daylight until their placement falls opposing or behind the sun.
Having this orrery as a daily practice will help you become aware of what goes on in our sky and the rate the celestial bodies move around our ecliptic plane. It is a good meditation to practice if you wish to be more aware of what is happening in space as percived from Earth.
My dining table orrery. unglazed ceramic, wax candle mold, peony arrangement and embroidered linen tablecloth. 2024
Table Set Up
Shown here is a diamond shape set up, but it can equally be done with a square or circle as long as the placement remains the same.
Moon Cycle Example Placements
New Moon
The moon and sun are both placed in the constellation Virgo. The moon is not visible in the sky.
First Quarter Moon
The moon is in Sagittarius and the Sun in Virgo. The moon will rise during the later hours of the day before night fall.
Full Moon
The moon is in Pisces and the Sun in Virgo. The moon will be seen rising in the east as the sun opposite to it in the west.
Last Quarter Moon
The moon is in Gemini and the sun in Virgo. The moon will be seen rising in the later hours of the night and will be visible in the night sky moving west as the sun begins to rise in the east
Sky Chart Resource
Click on the image to access the free Sky & Telescope sky chart which will give you the most accurate data for the placement of the celestial bodies for any given date.