 My name is Melanie. I work at the Canada Science and Technology Museum in Ottawa, Ontario, Canada. Today we're in the Helen Sawyer Hogg Observatory and we're going to talk to you about telescopes. This telescope was built in 1905 for Dominion Observatory in Ottawa, Ontario. Telescopes are instruments that allow us to see very distant objects really close. Astronomers use telescopes to look at things like planets, stars, galaxies that are billions of kilometres from the Earth. The first astronomer to ever use a telescope was Galileo back in 1609. That's over 400 years ago. Since not everybody has a telescope like ours, today I'm going to show you how to make your very own telescope at home. When you're done, it'll look something like this and you'll be able to look up at the stars in space or at objects on Earth. Let's head over to the lab and get started. So you might be wondering what our big telescope and this little telescope have in common. The secret is in the optics. The optics of a telescope refer to how the lenses or mirrors in the telescope are arranged to bring the picture right to your eye. For example, our telescope optics will use lenses just like your glasses. So say we're looking at a lighthouse in the distance. Light from the object is going to travel towards you in a straight line, but as soon as you put a lens between yourself and the object, the light gets bent. By putting two lenses between us and the object, we're actually concentrating the light into our eyes so we see a brighter image. So to make your telescope, you'll need one piece of black Bristol board, a stapler, black electrical tape, a pair of scissors, two magnifying glasses. Ideally one will be larger than the other. You'll need crayons or other decorations, a low temperature hot glue gun, and an empty chip tube container with the end cut out. Cut three pieces of Bristol board that fit around the tube. Measure two to be the same length as your tube and one to be twice the length. Use the glue gun to attach one of the smaller sheets to the outside of the tube. Roll the other small sheet and stick it into the tube to take its size and shape. Pull the tube halfway out, fasten it together with a stapler, and do the same to the other side. Apply hot glue all around the smaller tube then stick it into the larger one to make sure it doesn't slide around. You should now have your first tube covered in back paper inside and out. To make the sliding tube, use the longer piece of Bristol board to create another tube just like the last one and secure it with hot glue and electrical tape. It should slide smoothly in and out of the larger tube so don't glue it in place this time. This is the sliding focus for your telescope. Glue the first lens to the top of the chip tube and secure with electrical tape. Do the same with the second lens at the bottom of the sliding focus. If you're using two different size lenses, the smaller one should be placed at the bottom of the sliding focus. To add the finishing touches to your telescope, use crayon stickers or metallic pens to decorate the outside. To use your telescope, put your eye to the smaller end. Then move the two pieces back and forth to create your focus. If you're looking at an object on the ground, it'll be upside down. But if you're looking into space, you don't need to worry about it because all stars look the same whether they're right side up or upside down. I hope you enjoyed making your own telescope with us today. Remember, if you're interested in astronomy, visit your own local observatory. Or better yet, come visit us at the Canada Science and Technology Museum for some fun filled stargazing. See you there! Anybody seen a lighthouse? Where is that lighthouse?