How thick should a telescope mirror be?
Consider for example the dictum that the mirror of a reflecting telescope must be made of glass which has a thickness of at least one eighth of its diameter, and is said to be better still if it is as thick as one sixth of its diameter.
Can you make a telescope with flat mirrors?
A refractor employs lenses at both ends while a reflector uses a curved mirror at one end and a flat mirror at the other. It Is virtually impossible for an ordinary person to make his own lenses for a refracting telescope; but if you can get some lenses, perhaps from a war—surplus store, you can make a small telescope.
What kind of glass is used for telescope mirrors?
Lenses must be made from optical glass, a special kind of glass which is much purer and more uniform than ordinary glass. The most important raw material used to make optical glass is silicon dioxide, which must not contain more than one-tenth of one percent (0.1%) of impurities.
How smooth is a telescope mirror?
Telescope mirrors have the smoothest surfaces ever made. The highest “peaks” and lowest “valleys” on the mirror surface must be much smaller than the wavelength of light which we will be observing. Visible light has a wavelength around 550 nm (21.6 micro-inches, or 0.022 mils).
How do you polish a mirror on a telescope?
Put the mirror face-up onthe towel, and with the drain open, blast the mirror’s surface with room-temperature water for a few minutes. This will remove most dust and grit safely. From left to right: The safest way to remove grit from a telescope mirror is to blast the surface with tap water.
What is the largest mirror for a telescope?
The Hobby-Eberly Telescope at McDonald Observatory near Fort Davis, Texas, has the world’s largest telescope mirror. Because of the way HET is designed, however, astronomers use only 9.2 meters of the 11-meter (36-foot) mirror at any one time, making HET the world’s fourth-largest telescope.
Can we use mirror in a telescope what kind of mirror?
The Short Answer: Early telescopes focused light using pieces of curved, clear glass, called lenses. However, most telescopes today use curved mirrors to gather light from the night sky. The shape of the mirror or lens in a telescope concentrates light.
What material are space telescope mirrors made of?
beryllium
They are actually constructed from beryllium, a strong but lightweight metal. Each mirror piece weighs about 46 pounds (20 kilograms) on Earth.
What are telescope mirrors made out of?
The primary mirror in most modern telescopes is composed of a solid glass cylinder whose front surface has been ground to a spherical or parabolic shape. A thin layer of aluminum is vacuum deposited onto the mirror, forming a highly reflective first surface mirror.
How long does it take to grind a telescope mirror?
Just grinding the telescope mirror probably took 80-100 hours for me, but I was learning a lot and taking my time.
How long does it take to polish a telescope mirror?
STROKES: Use the Normal Stroke (1/3 Center-over-Center) for all polishing. TIME: A 6″ f/8 or 8″ f/6 mirror will typically be polished out in 6 to 12 hours or work, depending on mirror size and personal work style. This is very approximately one to two hours per inch of mirror diameter.
How much do telescope mirrors cost?
Each mirror costs US $20 million dollars and takes more than two years to build. Every stage of the manufacturing process calls for careful thought and meticulous planning. To begin, more than 17,000 kilograms of special glass are ordered and inspected for flaws.