a telescope similar in design to the Cassegrainian telescope but less widely used.
Lunar New YearRead more in this article about some frequently asked questions and fun facts related to our definitions.
The Meaning of “Rosh Hashana”Today is Rosh Hashana, the day that marks the beginning of the Jewish New Year. At sunset today, families and friends will gather to pray and then eat the traditional honey and apples, which symbolize the hope for a sweet new year. Rosh Hashana comes from Hebrew and most simply put means “beginning of the year.” Why isn’t the Jewish New Year on December 31st? The Hebrews used …
Origin of Gregorian telescope
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a form of reflecting astronomical telescope with a concave ellipsoidal secondary mirror and the eyepiece set behind the centre of the parabolic primary mirror
Word Origin for Gregorian telescope
C18: named after J. Gregory (died 1675), Scottish mathematician who invented it
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012