Refractor Telescope

I built a Refractor telescope. It is slightly weaker than the 20x and 30x telescope that Galileo used in November of 1609 to observe the night sky. With this he was able to see the four moons of Jupiter we now call the Galilean Satellites.

This is a replica of his telescope. As you can see it is not adjustable like the one I built.

With this telescope we can see images like these:

The Moons surface. Jupiter. Phases of the Moon.

The Telescope I have made is similar to the earliest know telescope created in 1608, created by Hans Lippershey. Several other people claim to have invented the Telescope, such as Zacharias Janssen a spectacle maker, and Jacob Metius. The design of these telescopes consisted of a convex objective lens and a Concave eyepiece. By 1911, they were building huge Keplerian telescopes with both lenses being convex, and compound eyepieces.

Isaac Newton created the first Refractor type Telescope in 1668. By this time telescopes were becoming huge and unwieldy. Thus the Achromatic lens was invented. This lens reduced color aberrations, and allowed for shorter and more functional telescopes.

Several important developments in reflecting telescopes were:

• John Hadley's production of larger paraboloidal mirrors in 1721.
• Silver glass mirrors introduced by Foucault in 1857.
• Aluminum coatings on mirrors 1932.

Here are some of Galileo's Drawings:

Illustration of the Moon by Galileo. Early drawing of the Moon. Drawing of the Moon and Jupiter.

The Ray diagram for my telescope looks like this:

The resolution of my Telescope is found using the Diameter (d) of the objective lens which is 203.2 mm so we us the equation of R = 138/d or R=138/203.2 Which = .679 So we have an arch second resolution of .679. I found the magnification power of my telescope by measuring the focal distances of the lenses. I did this by putting them to my eye and slowly backing away from a printed paper. When the text was clear, I had reached the focal distance. I then measured the distance and converted it into millimeters.

The equation for the magnification is Focal distance of the bigger lens / the focal distance of the smaller. So my equation looked like this:

203.2 mm / 11.5mm = 17.5 x