William Albert Hiltner (1914–1991) was an American astronomer, noted for his work leading up to the discovery of interstellar polarization.
 He was an early practitioner of precision stellar photometry, and a pioneering observer of the optical counterparts of celestial x-ray sources.
 Director of the Yerkes Observatory for many years, while there he designed and built a rotatable telescope for polarization studies and developed photometric instrumentation.
 He was the acting director of the Cerro Tololo Interamerican Observatory, then president of the Associated Universities for Research in Astronomy from 1968 until 1971, and was appointed Director of the University of Michigan Detroit Observatory in 1970,a post he held until 1982.
 He established MDM Observatory and led the construction of the Hiltner Telescope which is named for him.
Zacharias Janssen (also Zacharias Jansen or Sacharias Jansen) (1585 – pre-1632) was a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope.
 Janssen is sometimes also credited for inventing the first truly compound microscope.
 However, the origin of the microscope, just like the origin of the telescope, is a matter of debate.
Jacob (Jacobus; sometimes James) Metius (after 1571–1624/1631) was a Dutch instrument-maker and a specialist in grinding lenses.
 He was born and died in Alkmaar and was the brother of Adriaan Adriaanszoon (simply called Metius).
 He is one of three people associated with the invention of the telescope, the other two being Hans Lippershey and Zacharias Janssen.
 Not much of him is known besides his 1608 patent application for the invention.
 He died in Alkmaar between 1624 and 1631.
 Metius may have made many inventions but kept them secret.
 Before his death he destroyed them all to prevent anyone else from claiming them.
Hans Lippershey (1570 – buried 29 September 1619), also known as Johann Lippershey or Lipperhey, was a German-Dutch spectacle-maker.
 He is commonly associated with the invention of the telescope, because he was the first one who tried to obtain a patent for it.
 It is however unclear if he was the first one to build a telescope.
The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959.
 Prior to that the only available means of exploration had been observation from Earth.
 The invention of the optical telescope brought about the first leap in the quality of lunar observations.
 Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes; having made his own telescope in 1609, the mountains and craters on the lunar surface were among his first observations using it.
The XO Telescope is a telescope located on the 3,054 m summit of Haleakala on Maui, Hawaii, formed by a pair of 200 mm telephoto lenses.
 It is used by the XO Project to detect extrasolar planets using the transit method.
 It is similar to the TrES survey telescope.
 The construction of the one-of-a-kind telescope cost $60,000 for the hardware, and much more than that for the associated software.
The earliest known telescope appeared in 1608 in the Netherlands when an eyeglass maker named Hans Lippershey tried to obtain a patent on one.
 Although Lippershey did not receive his patent, news of the new invention soon spread across Europe.
 The design of these early refracting telescopes consisted of a convex objective lens and a concave eyepiece.
 Galileo improved on this design the following year and applied it to astronomy.
 In 1611, Johannes Kepler described how a far more useful telescope could be made with a convex objective lens and a convex eyepiece lens and by 1655 astronomers such as Christiaan Huygens were building powerful but unwieldy Keplerian telescopes with compound eyepieces.
DFM Engineering is an American telescope and optics manufacturer founded in 1979 by Frank Melsheimer in Longmont, Colorado.
 DFM makes medium size Cassegrain telescopes and their associated systems including telescope optics, control systems, and mounts.
 A range of pre-designed telescopes are made, as are various custom installations.
Jacobus Wittichius (Jacob Wittich) (1677–1739) was a German-Dutch philosopher, a Cartesian and follower of Burchard de Volder, and holder of controversial views on the nature of God.
The Orchard Hill Observatory is an astronomical observatory located at the highest point on the University of Massachusetts Amherst campus.
 Constructed in 1965, the observatory is a red brick building with a 16 inch Cassegrain reflector optical telescope.
 It is used for several community events and is regularly open for public viewing on Thursday nights.
 Originally the observatory was home to a 20” telescope, given to the department by an avid amateur who lived in central Massachusetts.
 It was a 1/10 scale model (loosely) of a larger 200” scope.
 Eventually, a crack was spotted during one of the re-aluminizings of the 20” mirror and the scope was no more.
 In the meantime, the department had been granted money associated with its move from Hasbrouck to the Grad Research Tower to buy a small telescope and put in on top of the GRC.
 The GRC had a small "isolation" pad built on its roof, which was supposed to be a mount for the scope, which could be accessed via a small open elevator.
 However, the GRC had terrible noise and gross vibration problems.
 The isolation pad never worked and there were too many safety concerns about using the roof of the building for observing.
 A 16" telescope was later bought from Competition Associates (a racing car company).
 That scope arrived in1976 but because of the problems with using the top of the GRC, the scope was never mounted there.
 In fact, it sat in the basement of Hasbrouck for perhaps 10 years, becoming known as the "Subterranean Telescope.”
 This situation finally led to the 20" being dissembled and the 16" scope being moved to Orchard Hill and installed in the dome there.
 The 16" was a major improvement in usability.
 As to what happened to the 20", the mirror may have been stored in the Astronomy Research Facility but the drive was most likely not kept.

Question: What German-Dutch spectacle-maker associated with Jacob Metius is associated with the invention of the telescope?
Answer: Hans Lippershey