On this page: Astronomy Lessons, FOSS, Science Masters Institute Resources, Daytime Moon Calendar, Planets' Natural Colors, How Many Moons?.

Astronomy Lessons

These activities are designed to support the Madison Metropolitan School District Science Curricula Scope & Sequence (which also matches well with the Wisconsin Science Standards).

FOSS Planetary Science Resources

FOSS Planetary Science Resource Page: This page contains links to resources we've gathered to supplement the FOSS Planetary Science Course we use in 8th grade in the Madison Metropolitan School District.

Science Masters Institute

Earth in the Solar System Workshop Resources: This is a collection of links and resources referred to in this teacher workshop conducted June, 2007 and 2009, at the planetarium.

Day-time Moon Calendar

Observe the moon in the daytime with your students! Go to the Daytime Moon Calendar to find out when and where to look.

Planets: True Colors

It's difficult to find a good collection of photographs which show the true or natural color of each of the planets. Here are some we've created.

How many moons? (Moon Count)

Teachers, are you having trouble keeping track of the number of moons for each planet? With improvements in technology, discoveries of more and more of the smaller moons have been coming in. Now they are detecting these objects down to only a couple of kilometers in diameter. So how small can these objects be and still be called a "moon"? There is no clear answer, because there is no clean cut-off for the size an object has to be in order to be called a moon. If you want to be safe, you can call them all natural satellites, but it's still okay to call them moons.

Here are the latest numbers. We will update them as new moons are found. Numbers between sources may vary. However these numbers are the generally accepted ones.

Planet Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto
# moons 00 00 01 02 79 82 27 14 05

Links to great sources of information about moons (natural satellites) in the solar system below.

Recent Updates:

  • October 17, 2019; 20 more moons for Saturn, discovered using the Subaru telescope.
  • July 16, 2018; 10 more moons for Jupiter, discovered using the 6.5-meter Magellan Telescopes.
  • March 23, 2017; 1 more moon for Jupiter, discovered using the Cerro Tololo Inter-american Observatory
  • March 8, 2016; 1 more moon for Jupiter, discovered using the Las Campanas Observatory.
  • July 15, 2013; 1 more moon for Neptune, discovered using the Hubble Space Telescope.
  • September 24, 2012; 1 more moon for Pluto, discovered this summer using the Hubble Space Telescope.
  • February 10, 2012; 2 more moons for Jupiter, discovered in 2011 using the Las Campanas Observatory.
  • July 20, 2011; 1 more moon for the dwarf planet Pluto, discovered using the Hubble Space Telescope.
  • July 20, 2011; 2 more moons for Jupiter, discovered in 2010 using the Hale Telescope and the Canada-France-Hawaii Telescope.
  • July 26, 2009; 1 more moon for Saturn, discovered using the Cassini spacecraft.
  • March 4, 2009; 1 more moon for Saturn, discovered using the Cassini spacecraft.
  • Summary for 2007: 4 more moons for Saturn; 3 discovered using the Subaru telescope, and another using the Cassini spacecraft.
  • Summary for 2006: 9 more moons discovered for Saturn; removed 2 moons that were previously thought to be new moons for Uranus (they appear to be previously known moons).
  • Summary for 2005: 14 more moons discovered for Saturn; 2 more moons discovered for Uranus; and 2 more moons discovered for Pluto.
  • Summary for 2004: 2 more moons discovered for Jupiter; 2 more moons discovered for Saturn; 6 more moons for Uranus, and 2 more moons for Neptune.
  • Summary for 2003: 21 more moons for Jupiter; 1 more moon for Saturn; 3 more moons for Neptune.
  • Summary for 2002: 11 more moons for Jupiter; 1 more moon for Uranus.

Links for up-to-date information on moons (natural satellites):