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Date of this Version



An open-access, electronic text edition, with notes and sky-map.


Samuel Danforth’s 1665 book on his observations of the great comet of 1664 (C/1664 W1) was one of the first works of astronomy printed in America. Danforth’s explanations of the various phenomena show his currency with contemporary knowledge: that the comet was a celestial body more distant than the moon; that it was not on fire, but that its flaming tail represented the reflection of the sun’s rays off exhalations from the head; that the tail always pointed away from the sun; that its motion in its path was uniform; and that it reached its perigee on December 18 (December 28, by the Gregorian calendar). He does suggest that its orbit was elliptical, although, in fact, it was observation of this comet that led Giovanni Alfonso Borelli to conclude that the path of non-periodic comets, such as this one, was parabolic. Halley’s discovery that some comets had elliptical (and thus periodic) orbits was yet to come. Other famous observers of this comet included Isaac Newton, Giovanni Domenico Cassini, Robert Hooke, Samuel Pepys, Stanislaus Lubinetski, and Matasaburou. This is the comet thought to be referenced by John Milton in Book II of Paradise Lost.

Danforth (1626–1674) was a Puritan minister, as well as an astronomer and almanack-maker, so his description includes a brief recap of famous comets in history and what disastrous events followed thereon. He also uses the comet as an occasion to warn New England of its falling away from its divine mission and to promote a general reformation of morals.

This online electronic text edition includes the complete text of the first edition, explanatory notes, a skymap of the comet’s path, orbital data on the comet, and a note on the text. The orbital data allows interested observers to re-create the observations at an online planetarium website. Includes links. The entire work can be printed out on 16 landscape-oriented pages.