http://www.skyandtelescope.com.au 23and fifth magnitude, both men observed the star every
clear night. Neither saw another dimming event until
both witnessed one on December 28, 1782. They found the
brightness remained approximately constant except for a
seven-hour dip every 2 days, 20 hours, and 45 seconds. The
two realised that the cause of such a pattern might be one
body passing in front of another, and each speculated in his
observing journal. Goodricke wrote:[Algol’s variation] can’t be accounted for in any other
manner than supposing it to have suffered an Eclipse ... by the
interposition of a Planet revolving around it. ...Edward Pigott elaborated, writing:Having, on further consideration stronger reasons to believe
that what I wrote to Mr. J. Goodricke on the 29th of December
1782 may possibly happen induces me to make the following
memorandum of it — the opinion I suggested was that the
alteration of Algol’s brightness was maybe occasioned by a Planet
of about half his size, revolving around him, and therefore does
sometimes eclipse him partially. ...In May 1783, William Herschel confirmed the discovery of
Algol’s variability, and Goodricke sent his report to the Royal
Society. In the report’s conclusion, Goodricke wrote that he... should imagine [Algol’s variation] could hardly be
accounted for otherwise than either by the interposition of a large
body revolving round Algol, or some kind of motion of its own,
whereby part of its body, covered with spots or such like matter, is
periodically turned towards the earth.Academy. The Warrington mathematics curriculum included
a significant amount of astronomy, and John’s mathematics
notebook includes a sketch of the sky. From the position of
the Moon and the times indicated in the text, it’s clear that
he was observing in late November 1779. A total eclipse of
the Moon occurred on November 23, 1779. Was Goodricke
checking his homework or merely planning to observe an
astronomical event? We don’t know, but we do know that he
was interested in observing before meeting Edward Pigott.
In 1781 Goodricke completed his studies at Warrington and
rejoined his family in York.
That same year, Edward Pigott (1753–1825) also moved
to York with his parents. Edward’s father Nathaniel used
astronomical observations for determining latitude and
longitude, and Edward learned the art of observing from him.
In York, Nathaniel constructed a two-story stone observatory.
The instruments — telescopes, a quadrant and a theodolite
— came from London’s finest instrument makers. Nathaniel
was a member of the Royal Society of London, and both
Pigotts kept abreast of current astronomical developments
through correspondence with astronomers such as William
Herschel and Charles Messier.
Edward Pigott’s astronomical interests ranged further than
his father’s, however. He frequently compared the apparent
stellar magnitudes reported by Flamsteed with those of earlier
observers such as Tycho and Ptolemy. One of Edward’s early
journals contains a list of publications entitled “Authors on
Variable Stars”. When Goodricke joined him, Pigott suggested
that they systematically observe suspected variables.
After Goodricke first saw Algol’s “very unexampled
change,” in which the star’s brightness dropped from an
estimated third magnitude to somewhere between fourthTWORKING FROM HOME In 1782, John Goodricke lived and observed near the close of York Minster. In 1949, Sidney Melmore used dates,
times, and notes written in Goodricke’s observing logs to argue that Goodricke observed from the north window on the top floor of the southeast
wing (at right, behind the tree branch) of the Treasurer’s House, looking south toward the cathedral. However, records show that the Goodricke
family rented rooms from Edward Topham, who owned the northwest wing of the house (left).LIGHT CURVES: GREGG DINDERMAN /
S&T;
LINDA FRENCH (2)