Moons of Jupiter Astronomical Telescope

An early achromatic refractor telescope signed Dollond. This astronomical telescope is called "the Moons of Jupiter Telescope." The images observed are inverted, suitable for viewing celestial bodies but not used for terrestrial viewing.

This handheld single-draw telescope was used to determine longitude, as first observed by Galileo in 1610. Galileo used the timing of the eclipses of Jupiter's moons to determine longitude on Earth—a problem that was very important for navigation and cartography.

Signed Dollond, London

2 3/4-inch objective lens
27-inch focal length
3-inch diameter mahogany barrel