|Cassegrains||Back to scope choices.....|
In 1672, Jacques Cassegrain (1652-1712) proposed his telescope design, but probably never constructed any. The first known Cassegrain telescope was built by James Short (1710-1768). There are two common Cassegrain telescopes available on the market: - the Schmidt-Cassegrain ("SCT") and the Maksutov-Cassegrain ("Mak-Cas").
The Schmidt-Cassegrain, like this Meade 10-inch LX200, utilizes a concave primary mirror to gather light and reflect it to a convex, adjustable secondary mirror. The light is then reflected through a hole in the primary mirror to the eyepiece. This design helps to remove coma, a problem with Newtonian reflectors. It also places the focus at a more symmetrical position, allowing for the easier use of cameras.
The Maksutov-Cassegrain used to be considered rare, but lately has made a bid for widespread popularity, showcased by the iOptron MAK 152mm Telescope. Instead of an aspherical corrector plate like the one used in the Schmidt, the Maksutov utilizes a crescent-shaped lens. This corrector plate is shaped like a shallow bowl, which acts as a secondary mirror. Meade, Vixen, and iOptron are the main manufacturers of new Mak-Cass telescopes.
|Learn about another type of Telescope:|
What type of telescope should you buy?
Nomenclature - the typical Dob
What's an f/number? - Fast vs slow
What you can see... and what you WON'T see
The Cost of Amateur Astronomy
Finderscopes, Telrads, etc.
What is "GO-TO"?
Recommendations - GO-TO Systems
How things REALLY look in the eyepiece