The Stellarota … an early American planisphere

Invented by Rev. Amos Pettengill / Projected and drawn by C. M. Doolittle and S. B. Munson / Engraved by N. & S. S. Jocelyn, STELLAROTA. [New Haven]: A. Goodyear & Son, February 1st, 1828.
Hand-colored engraving in two sections, an outer section with circular opening and a recessed, moveable inner disk bearing a star map, overlaid with crossing brass rods and brass wire ring. Housed in the original wood frame. Printed instructions on verso, along with a brass ring for turning the moveable disk. Overall dimensions including frame, 10 1/8”h x 11 ½”w.

Only the fifth known example of Amos Pettengill’s 1828 Stellarota, possibly the earliest known American planisphere.

Reverend Amos Pettengill (1780-1830), a pastor who served in various New England communities, was living in Connecticut when he published A View of the Heavens (1826), an astronomical textbook for children. A brief mention of the Stellarota in the textbook (p. 79) suggests that Pettengill had developed a working model by that time.

In his Rittenhouse article on the instrument, Ron Smeltzer observes that

“planispheres in the modern general form with an azimuthal polar equidistant projection and an observer’s window seem to date from the mid-1850s in England and the United States, although a much earlier one, dated 1812, with a stereographic projection has been described.”

Pettengill’s device may thus be the earliest known to display “the key features of a modern planisphere, a rotatable star map with time and date scales and a window to define the observer’s view.” (p. 31) The Stellarota uses an ingenious mechanism to adjust for the user’s latitude, involving a loop of brass wire whose shape—representing the observer’s window—can be adjusted by raising and lowering a vertical brass rod to which the loop is attached (This mechanism appears to be entirely present on our Stellarota but is not operable, though I suspect that with care it may be put in working order.)

Smeltzer notes that “The star map itself seems to be somewhat of an enigma, as it is a projection from outside the celestial sphere; hence, not convenient for an observer looking up to the sky.” (p. 34) Although no mention is made of it on the Stellarota itself, Pettengill resolves this enigma in A View of the Heavens when he notes of a similar moveable circle that accompanied the book that “All the bright stars are here presented to your view just as they would be, if reflected from water, or a horizontal mirror.” A reflected image of the stars presents their positions in reverse, as if the observer were viewing them “from outside the celestial sphere,” exactly as on the Stellarota… or, for that matter, as on a celestial globe, for which the Stellarota was intended as an inexpensive substitute.

The Stellarota was manufactured by A. Goodyear & Son, the “son” being Charles Goodyear, who would later win fame for his rubber manufacturing process. The instrument received at least one favorable review, in Silliman’s American Journal of Science and Arts:

“The Rev. Amos Penttengill [sic] of Salem, Conn., has contrived a very ingenious instrument for the use of students of astronomy…. [It] affords, at a very cheap rate, many of the facilities for studying the heavenly bodies, usually supplied only by celestial globes….


“We cordially recommend this little instrument to the attention of preceptors of academies, who are not already furnished with a celestial globe, and especially to private learners, who will find in it a most useful guide and auxiliary…” (Benjamin Silliman, ed., American Journal of Science and Arts, vol. XVI (July, 1829) New Haven: Hezekiah Howe et al, 1829, pp. 363-365.)

Judging from its rarity however, the Stellarota was not a commercial success. Smeltzer was only able to locate one in the private collection of Valerie Young (lacking the instructions on the back, now at Princeton and viewable on line), another (badly incomplete) at Yale, and a third, offered for sale in 2005 by James Arsenault & Company (current location not known). Another, apparently missing the glass, is held by the historic Wyck House in Philadelphia.

Ronald Smeltzer, “An Early American Planisphere: Pettengill’s Stellarota of 1828” in Rittenhouse: Journal of the American Scientific Instrument Enterprise, Vol. 18, No. 2, December 2004, pp.31-39 and “An Early American Planisphere: Pettengill’s Stellarota of 1828 – Addendum” in Rittenhouse, Vol. 19, No. 1, June 2005, pp. 63-64. OCLC 57458478 (Yale only). Much of the foregoing description was borrowed with the permission of James Arsenault.


Strikingly good condition for such a fragile item, with some minor soiling and toning to the engraving; minor chipping, scratching and cracking to veneer of frame; and the instructions darkened with some abrasion and loss to the blank margin and printed border.