Born Stowmarket, Suffolk, England, 14 March 1903
Died Stowmarket, Suffolk, England, 6 October 1981
John Prentice discovered the Giacobinid (Draconid) meteor shower and Nova DQ Herculis 1934, but his main contributions to astronomy came through his careful supervision of the British Astronomical Association [BAA] Meteor Section for over 30 years. Prentice played an important role in establishing radar observation as a primary technique for studying meteors.
A lawyer by profession, Manning Prentice (as he was known to his friends) acquired an interest in astronomy as a schoolboy. He first began observing the Moon and planets with a small refractor, and later meteors with his naked eye. After joining the BAA in 1919, Prentice continued his meteor observations and was appointed leader of the BAA Meteor Section in 1923, holding that position until 1954.
In 1915, Reverend Martin Davidson (1880–1968) pointed out that the orbit of the short-period comet 21P/Giacobini – Zinner passed close enough to that of the Earth that it might result in a meteor shower on about 10 October each year. No such activity was seen until Andrew Crommelin calculated that on 10 October 1926 the orbits of the comet and the Earth would intersect. Acting on Crommelin’s prediction, Prentice took up a routine watch the previous evening and was rewarded with the observation of a strong meteor shower – Prentice estimated meteors appeared at a rate of 17 per hour for one observer – with a radiant very near that projected by Davidson. William Denning published a similar conclusion about this shower at an earlier date than Prentice, but priority for the discovery clearly belongs to Prentice as the earliest observer. A spectacular return of the Giacobinid meteor shower in 1933, when the Earth crossed the comet’s orbit 80 days after the passage of the comet (as opposed to 19 days before the comet’s passage in 1926), confirmed not only the relationship of the shower with the comet but also revealed that the duration of the shower was sharply limited to only 4½ h. The zenith hourly rate for the 1933 Giacobinid shower was estimated at between 4,000 and 6,000 meteors per hour. Unfortunately, the skies were cloudy in England, and the information on this shower was provided by Reverend William Frederick Archdall Ellison (1834–1936) at the Armagh Observatory and by observers on the European Continent.
Prentice’s familiarity with the night sky was an important prerequisite for his program of meteor observation and also contributed to his discovery, early on the morning of 13 December 1934, of a nova in the constellation of Hercules. While taking a break from his tiring routine of meteor counting, Prentice noticed something wrong in the appearance of the head of Draco. The problem was quickly traced to an interloping star that was promptly reported to the Royal Greenwich Observatory. Prentice’s expeditious reporting facilitated valuable premaximum spectroscopic observation of Nova DQ Herculis. An independent discovery of this nova was made within hours at Delphos, Ohio, by another amateur astronomer, Leslie Peltier .
In June 1937, Prentice married Elizabeth Mason Harwood; their union resulted in the birth of four children. The resulting obligations, as well as those associated with his leadership in the congregation of the Stowmarket Congregational Church, must have increased the burden of his avocational interests, but Prentice’s zeal for observation remained comparatively undiminished. A further complication arose as a result of the bombing of the church in 1941. For 14 years thereafter, Prentice shouldered a heavy burden as he led the membership’s effort to rebuild the structure and preserve the integrity of the congregation. Prentice was active as a leader of youth activities in the church and served as a lay minister and church secretary as well.
After World War II, (Sir) Bernard Lovell contacted Prentice and his BAA meteor section for assistance in tracing the relationship between meteor activity and apparently spurious radar signals, interference that could not be traced to cosmic-ray activity. During the Perseid shower in August 1946, Prentice traveled to Jodrell Bank to assist with the correlation of radar signal reception with the appearance of specific meteors; the correlation was immediately evident. Prentice and John Porter worked with Lovell and others at Jodrell Bank to apply this technique to good advantage in investigations of meteor streams during daylight hours, and streams of meteors too faint to be seen with the naked eye at night.
In 1935, the BAA and American Association of Variable Star Observers honored Prentice for his discovery of Nova DQ Herculis by awarding him their Walter Goodacre Medal and D. B. Pickering Medal, respectively. In 1953, the Royal Astronomical Society honored his work on meteors with the award of its Jackson-Gwilt Gift and Medal while the University of Manchester conferred an honorary master of arts degree on Prentice in that same year.