Hammett’s Planisphere

Hammett’s Planisphere is a heavy paperboard chart used to determine the positions of stars at any given moment from latitude 40˚N. The circular base contains a celestial map of stars and constellations and is is overlaid with a revolving top cardstock that has one large center cut out revealing a star chart. Every 90 degrees from center is one of four cut windows that can used to easily rotated the top piece to account for time of months, hour in the day, degrees and Zodiac calandar. A printed instruction sheet is attached to the back. The Hammett's Planisphere was marketed for school use and sold though their catalog and in their retail stores.

Produced for educational use, this model contains ornamental embossed embellishments that help to date it. It is the same physical format as the popular Philips' Planisphere, created by bookseller George Philip & Sons, London, though theirs is usually at latitude 42. Thomas Whittaker (see PH.322588) also produced a similar version during this period. An earlier simple planisphere was produced for schools by Henry Whitall and J. L. Hammett Co.later discontinued the ornamental version for a plainer form like the Miller Planisphere.

John Hammett began selling erasers and slating paint for chalkboards in Rhode Island in 1863, moving to Boston in 1865. In 1890, new owners expanded the firm into all forms of paper school supplies. The firm was renamed the J. L. Hammett Co. and after 1895 opened factories in New York, New Jersey, and Massachusetts. They moved their headquarters to Braintree, Mass. in 1967; and operated over 50 retail stores from 1974 to 2005.

Currently not on view