A total solar eclipse occurred at the Moon’s descending node of orbit on Saturday, December 4, 2021,[1][2][3] with a magnitude of 1.0367. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's and the apparent path of the Sun and Moon intersect, blocking all direct sunlight and turning daylight into darkness; the Sun appears to be black with a halo around it. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. This eclipse was unusual as the path of the total eclipse moved from east to west across West Antarctica, while most eclipse paths move from west to east. This reversal is only possible in polar regions. Its path across Antarctica crossed near Berkner Island, traversed an arc over the continent and passed over Shepard Island.[4][5]
Images
Animated path
NASA's DSCOVR Satellite photo
As observed by the Royal Navy (HMS Protector) off South Georgia
This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[7]
Solar saros 152, repeating every about 18 years and 11 days, contains 70 events. The series started with a partial solar eclipse on July 26, 1805. It has total eclipses from November 2, 1967, to September 14, 2490; hybrid eclipses from September 26, 2508, to October 17, 2544; and annular eclipses from October 29, 2562, to June 16, 2941. The series ends at member 70 as a partial eclipse on August 20, 3049. The longest total eclipse will occur on June 9, 2328, at 5 minutes and 15 seconds; the longest annular eclipse will occur on February 16, 2743, at 5 minutes and 20 seconds.[8]
The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's descending node.
21 eclipse events, progressing from north to south between July 11, 1953 and July 11, 2029