If you like the website and want to contribute to the running costs then please do so below. All contributions are most welcome.

PayPal - The safer, easier way to pay online.

The time between successive oppositions of an object as viewed from Earth. The synodic period is longer than the object's orbital period as the object needs extra time to "catch up" to the movement of our planet along its own orbit.

For example, the orbital period of the Moon is 27.32 days but the time between successive full Moons (synodic period) is 29.5 days.

Glossary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z