An annular solar eclipse occurred at the Moon's descending node of orbit on Wednesday, September 23, 1987, with a magnitude of 0.9634. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring only 5 days after apogee (on September 18, 1987, at 4:00 UTC), the Moon's apparent diameter was smaller.
Annularity was visible in the Soviet Union (today's Kazakhstan), China (including Shanghai), southwestern Mongolia, Okinawa Islands of Japan except Kume Island and the southwestern tip of Kerama Islands, the Federal States of Micronesia, Papua New Guinea, Solomon Islands, Rotuma Islands of Fiji, Wallis Islands and West Samoa (the name changed to Samoa later). A partial eclipse was visible for parts of South Asia, Southeast Asia, East Asia, Australia, Oceania, and Hawaii.
Observation Five radio observation stations were present in China at the time of the eclipse, two of which were within the annularity, in Ürümqi and Shanghai respectively. A partial solar eclipse was observed from the other three, including one in Nanjing where the eclipse was close to annularity, and the rest two in Beijing and Kunming. The Department of Mathematics and Physics of the Chinese Academy of Sciences and the Chinese Astronomical Society held a meeting in Kunming in December 1986, deciding that on-site observation would be conducted at each station, among which the Shanghai Astronomical Observatory was considered to have the best location with a larger magnitude of the eclipse, longer duration and larger solar zenith angle. The Shanghai Astronomical Observatory conducted observations with seven different wave bands using a 25-metre radio telescope. The Yunnan Astronomical Observatory located in Kunming also conducted a multi-band joint observation of the partial solar eclipse.
The Chinese Research Institute of Radio Wave Propagation conducted observations with a high-frequency skywave radar located in Xinxiang on the southern limit of annularity. Uneven structure and motion were observed in the ionosphere, the highest operating frequency was found changed during the eclipse, and large-scale fluctuations continued after the eclipse.
Eclipse details Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the Moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.
+September 23, 1987 Solar Eclipse Times Event Time (UTC) First Penumbral External Contact 1987 September 23 at 00:15:50.5 UTC First Umbral External Contact 1987 September 23 at 01:20:19.5 UTC First Central Line 1987 September 23 at 01:22:07.2 UTC First Umbral Internal Contact 1987 September 23 at 01:23:55.0 UTC First Penumbral Internal Contact 1987 September 23 at 02:33:48.6 UTC Greatest Duration 1987 September 23 at 02:45:44.7 UTC Equatorial Conjunction 1987 September 23 at 02:54:28.0 UTC Ecliptic Conjunction 1987 September 23 at 03:09:08.4 UTC Greatest Eclipse 1987 September 23 at 03:12:21.6 UTC Last Penumbral Internal Contact 1987 September 23 at 03:51:20.8 UTC Last Umbral Internal Contact 1987 September 23 at 05:01:01.1 UTC Last Central Line 1987 September 23 at 05:02:46.3 UTC Last Umbral External Contact 1987 September 23 at 05:04:31.2 UTC Last Penumbral External Contact 1987 September 23 at 06:08:54.0 UTC
+September 23, 1987 Solar Eclipse Parameters Parameter Value Eclipse Magnitude 0.96337 Eclipse Obscuration 0.92807 Gamma 0.27869 Sun Right Ascension 11h58m25.1s Sun Declination +00°10'17.1" Sun Semi-Diameter 15'56.2" Sun Equatorial Horizontal Parallax 08.8" Moon Right Ascension 11h58m55.2s Moon Declination +00°23'45.5" Moon Semi-Diameter 15'07.6" Moon Equatorial Horizontal Parallax 0°55'30.9" ΔT 55.7 s
Eclipse season
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.
+ Eclipse season of September–October 1987 September 23Descending node (new moon) October 7Ascending node (full moon) Annular solar eclipseSolar Saros 134 Penumbral lunar eclipseLunar Saros 146
Related eclipses Eclipses in 1987 A hybrid solar eclipse on March 29. A penumbral lunar eclipse on April 14. An annular solar eclipse on September 23. A penumbral lunar eclipse on October 7.
Metonic Preceded by: Solar eclipse of December 4, 1983 Followed by: Solar eclipse of July 11, 1991
Tzolkinex Preceded by: Solar eclipse of August 10, 1980 Followed by: Solar eclipse of November 3, 1994
Half-Saros Preceded by: Lunar eclipse of September 16, 1978 Followed by: Lunar eclipse of September 27, 1996
Tritos Preceded by: Solar eclipse of October 23, 1976 Followed by: Solar eclipse of August 22, 1998
Solar Saros 134 Preceded by: Solar eclipse of September 11, 1969 Followed by: Solar eclipse of October 3, 2005
Inex Preceded by: Solar eclipse of October 12, 1958 Followed by: Solar eclipse of September 1, 2016
Triad Preceded by: Solar eclipse of November 22, 1900 Followed by: Solar eclipse of July 24, 2074
Solar eclipses of 1986–1989
Saros 134
Metonic series
Tritos series
Inex series
Notes
References