The telescope is a complex and sensitive instrument which allows for viewing
and measuring objects from great distances. The quality of observation depends on
the lenses or mirrors, the stability of the tube, the telescope’s mount, and how
easily it can be moved. The first telescopes were developed in 1608 in the
Netherlands. In 1610, Galileo began making astronomical observations with a
telescope, and saw the moons of Jupiter, mountains and valleys on the moon, and new
fixed stars. Several of these were contrary to Aristotelian principles, which
explained that the sun, moon, and stars were perfect spheres embedded in fixed
concentric rings and revolved forever at fixed rates.
Lenses and Mirrors
The usefulness of early telescopes for astronomical observation was limited by
several factors. Lenses and mirrors, which were used to collect light and magnify
far-away objects, were difficult and costly to make as they required expert grinding
to create the shape and clarity for a telescope. In the 19th century, only a few
craftsman could create clear telescope lenses for use in the more powerful telescopes
needed for astronomical research.
Mounts and Positioning
Many early telescopes were very large and cumbersome, meaning they could not easily
be repositioned to track astronomical features as they moved across the sky. Telescopes
also required special and complex mounts. The mounting for a telescope allows the telescope
to rotate around an axis so that it may follow objects across the sky. These mounts require
fine tuning so that the movements are smooth and accurate. Haverford, when purchasing its
second telescope, sought advice on the effects of using a smaller mount for the new
telescope--Haverford was advised against this.