An annular solar eclipse occurred at the Moon's descending node of orbit on Thursday, April 29, 1976,[1] with a magnitude of 0.9421. 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 about 1.9 days after apogee (on April 27, 1976, at 13:30 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible from North Africa, Greece, Turkey, Middle East, central Asia, India, China. 5 of the 14 eight-thousanders in Pakistan and China—Nanga Parbat, K2, Broad Peak, Gasherbrum II and Gasherbrum I, lie in the path of annularity. A partial eclipse was visible for parts of the Canadian Maritimes, North Africa, Central Africa, Europe, the Middle East, Central Asia, and South Asia.
The Institute of Physics and Institute of Mathematics of the Chinese Academy of Sciences and the Xinjiang Earthquake Team conducted observations of gravitational effects using gravimeters, inclinometers, pendulum clocks and seismometers in southwestern Hotan County, Hotan Prefecture, Xinjiang near the Karakoram Pass at an altitude of 5500m (18,000feet). Results showed that the gravitational acceleration had no obvious effect within the accuracy of the instruments. No inclination was recorded on the photosensitive paper of the inclinometer due to the width of its lines. Three inclinations were pen-recorded, whose time and direction were clearly related to that of the eclipse. Due to the difficult conditions with the high altitude, the observation team was unable to obtain more comparative data.[3]
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.[4]
| First Penumbral External Contact | 1976 April 29 at 07:23:05.3 UTC | |
| First Umbral External Contact | 1976 April 29 at 08:30:13.1 UTC | |
| First Central Line | 1976 April 29 at 08:32:52.8 UTC | |
| First Umbral Internal Contact | 1976 April 29 at 08:35:32.9 UTC | |
| First Penumbral Internal Contact | 1976 April 29 at 09:52:32.8 UTC | |
| Ecliptic Conjunction | 1976 April 29 at 10:20:15.6 UTC | |
| Greatest Eclipse | 1976 April 29 at 10:24:17.7 UTC | |
| Greatest Duration | 1976 April 29 at 10:30:53.5 UTC | |
| Equatorial Conjunction | 1976 April 29 at 10:33:23.0 UTC | |
| Last Penumbral Internal Contact | 1976 April 29 at 10:55:47.8 UTC | |
| Last Umbral Internal Contact | 1976 April 29 at 12:12:56.6 UTC | |
| Last Central Line | 1976 April 29 at 12:15:35.7 UTC | |
| Last Umbral External Contact | 1976 April 29 at 12:18:14.3 UTC | |
| Last Penumbral External Contact | 1976 April 29 at 13:25:23.3 UTC |
| Eclipse Magnitude | 0.94208 | |
| Eclipse Obscuration | 0.88752 | |
| Gamma | 0.33783 | |
| Sun Right Ascension | 02h27m19.6s | |
| Sun Declination | +14°34'10.4" | |
| Sun Semi-Diameter | 15'52.7" | |
| Sun Equatorial Horizontal Parallax | 08.7" | |
| Moon Right Ascension | 02h27m02.8s | |
| Moon Declination | +14°51'57.3" | |
| Moon Semi-Diameter | 14'44.9" | |
| Moon Equatorial Horizontal Parallax | 0°54'07.6" | |
| ΔT | 46.8 s |
See also: Eclipse cycle. 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.