How a Telescope Works with a Hyperbolic Mirror

Many telescopes use hyperbolic or parabolic mirrors for seeing the stars.

A hyperbola is similar to a parabola. Hyperbolic, or parabolic mirrors found in telescopes are a concave mirror. Sir Isaac Newton designed the first practical mirror to use in a telescope.

Telescopes

All telescopes gather and focus light. A refractor telescope uses ground lenses to focus light and magnify the image. Binoculars use the refractor principle. A hyperbolic telescope uses a curved mirror to focus the light forward onto a mirror or prism set at 45 degrees to the tube. This reflects the image upward into an eyepiece.

Reflector Telescopes

Sir Isaac Newton developed the reflector or hyperbolic telescope to eliminate the distortion and flare that refractor telescopes produced. There are several similar designs classified as reflector telescopes that use a version of a hyperbolic mirror.

Hybrid Telescopes

Light enters a hybrid telescope through a corrective lens on the front of the tube. The light is then forwarded by hyperbolic mirror to a lens that reflects it back through an eyepiece for viewing.

References

• Naperville Astronomical Association: How Telescopes Work
• Astro-Tom: Types of Telescopes
• Universe Today: Reflector Telescope