Explore Scientific Galileoscope 50mm Refractor Telescope STEM Kit

Build your own telescope, then see Saturn's rings with it

The Explore Scientific Galileoscope 50mm Refractor Telescope STEM Kit is a telescope you put together yourself in minutes, with no tools or glue. It was created by astronomers, optical designers and educators for the 2009 International Year of Astronomy, and more than 250,000 kits have gone to classrooms and families in over 110 countries. Building it teaches how lenses form images and magnify. Once it's built, it's a real 50mm telescope that shows lunar craters, Jupiter's moons and Saturn's rings. Explore Scientific has made and distributed the Galileoscope since 2018.

Key specs: 50mm (2") objective · 500mm focal length, f/10 · 20mm eyepiece for 25x · 2x Barlow for 50x · 17x Galilean eyepiece option · 1.25" focuser · fits most camera tripods · no tools or glue needed

What you'll see

• The Moon: craters, mountains and the long shadows along the line between day and night.
• Planets: Jupiter's four bright moons changing position night to night, and Saturn's rings.
• Star clusters: at 25x the 1.5° field is about three full Moons wide, enough to take in the whole Pleiades, one of the sights Galileo described.

How it works

• Snap-together assembly: the tube, objective lens and focuser fit together by hand. Assembly instructions are on galileoscope.org.
• Three ways to view: the 20mm eyepiece gives 25x. The included lens module works as a 2x Barlow for 50x, or as a Galilean eyepiece for an upright 17x view like Galileo's own telescopes.
• A standard 1.25" focuser: it accepts other 1.25" eyepieces, so the telescope can grow with the student.
• Classroom friendly: it's used to teach lenses, magnification and field of view, and suits students from about age 8 with adult help.

What to add for the best results

• A tripod (required for steady views): the Galileoscope Tripod is made for it and converts from tabletop to full height. The base also fits most standard camera tripods.
• A lower-power eyepiece: the Explore Scientific 52° 25mm gives 20x and a wider view for finding objects. The 52° 15mm gives 33x.
• Storage: the Explore Scientific eyepiece case keeps eyepieces and small parts together.

Safety: never point the Galileoscope at the Sun without a proper solar filter covering the front of the telescope.

See all Explore Scientific telescopes.

What's in the box

• All parts to build the 50mm f/10 Galileoscope refractor
• 20mm eyepiece
• Lens module that works as a 2x Barlow or 17x Galilean eyepiece
• Assembly instructions

The tripod and solar filter are sold separately.

Galileoscope FAQ

Is it hard to build?

No. It goes together by hand in minutes with no tools or glue. Younger students should build it with an adult.

Can I really see Saturn's rings?

Yes. At 50x with the Barlow, Saturn's rings are visible, along with Jupiter's moons and plenty of lunar detail.

Do I need a tripod?

Yes, for steady views. Hand-holding a telescope at 25x or 50x makes the image shake. The Galileoscope Tripod is made for it, or use any camera tripod.

Is it good for a classroom?

That's what it was designed for. Students learn how lenses work while they build it, and then use it to observe.

Can I use other eyepieces?

Yes. The focuser takes standard 1.25" eyepieces. Divide 500 by the eyepiece's focal length to get the magnification.

Specifications