The first scientifically based and accurate predictive map of a solar eclipse

By HALLEY, Edmond, 1715 

A Description of the Passage of the Shadow of the Moon, over England In the Total Eclipse of the SUN, on the 22nd Day of April 1715 in the Morning

Celestial
  • Author: HALLEY, Edmond
  • Publication place: London
  • Publisher: John Senex
  • Publication date: 1715.
  • Physical description: Engraved map, good condition.
  • Inventory reference: 11387

Notes

Sir Edmond Halley was one of the first, and greatest, astronomers to apply himself to the study of eclipses. A pioneer of predictive astronomy, his work was a notable advance in the field. While there are numerous earlier predictive maps of eclipses, Halley is credited with producing the first scientifically-based and accurate predictive map of an eclipse, for that of the solar eclipse of 22nd April, 1715, forecasting the passage of the eclipse over England and southern Scotland, accurate to about four minutes, marking the moon’s shadow on this map by the heavily shaded oval disk and track.

While the eclipse was a natural phenomenon to a scientist of his stature — people will see that there is nothing in it more than Natural, and no more than the necessary result of the Motions of Sun and Moon” — he was also concerned (as indeed were other advertisers in the daily papers of the day), that

The like Eclipse having not for many ages been seen in the Southern Parts of Great Britain, I thought it not improper to give the Publick an Account thereof, that the sudden darkness, wherein the Starrs will be visible about the Sun, may give no surprize to the People, who would, if unadvertized, be apt to look upon it as Ominous, and to interpret it as portending evill to our Sovereign Lord King George and his Government…“

The text goes on to give timings for the eclipse and the areas affected, under the path.

The map was advertised for the first time in the Post Boy (issue 3098) for 15th — 17th march, 1715 thus:
This day is publish’d, the two following PRINTS. Mr Professor Halley’s Description of the Shadow of the Moon over England in the total Ecclipse of the Sun on the 22nd Day of next Month in the Morning, when the sudden darkness will make the Stars visible about the Sun; the like Ecclipse having not for 500 Years been seen in the Southern Parts of Great Britain… printed for J. Senex, at the Globe in Salisbury-Court; and W. Taylor, at the Ship in Pater-noster-row; Pr. of each 6d. …”.

This is the second state of the plate, with two additions outside the lower border: Sold also by William Taylor at the Ship in Paternoster Row.’ and Entered in the Hall Book [of the Stationer’s Company].” It is assumed that Taylor’s imprint was quickly added to the plate — they were frequent partners in publications — hence the rarity of the first state. However, only seven institutional locations for this second state, and two examples for sale in the last thirty years, have been traced.