An annular solar eclipse occurred at the Moon's ascending node of orbit between Tuesday, January 15 and Wednesday, January 16, 1991,[1] with a magnitude of 0.929. 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 3.5 days after apogee (on January 12, 1991, at 11:00 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible in southwestern Western Australia, Tasmania, New Zealand and French Polynesia. A partial eclipse was visible for parts of Indonesia, Australia, Oceania, and Antarctica.
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.[3]
| First Penumbral External Contact | 1991 January 15 at 20:51:57.9 UTC | |
| First Umbral External Contact | 1991 January 15 at 21:57:45.6 UTC | |
| First Central Line | 1991 January 15 at 22:00:52.7 UTC | |
| First Umbral Internal Contact | 1991 January 15 at 22:04:00.1 UTC | |
| First Penumbral Internal Contact | 1991 January 15 at 23:15:21.5 UTC | |
| Greatest Duration | 1991 January 15 at 23:40:06.1 UTC | |
| Equatorial Conjunction | 1991 January 15 at 23:44:29.4 UTC | |
| Ecliptic Conjunction | 1991 January 15 at 23:50:36.9 UTC | |
| Greatest Eclipse | 1991 January 15 at 23:53:51.3 UTC | |
| Last Penumbral Internal Contact | 1991 January 16 at 00:32:36.2 UTC | |
| Last Umbral Internal Contact | 1991 January 16 at 01:43:50.2 UTC | |
| Last Central Line | 1991 January 16 at 01:46:55.5 UTC | |
| Last Umbral External Contact | 1991 January 16 at 01:50:00.3 UTC | |
| Last Penumbral External Contact | 1991 January 16 at 02:55:44.0 UTC |
| Eclipse Magnitude | 0.92901 | |
| Eclipse Obscuration | 0.86306 | |
| Gamma | −0.27275 | |
| Sun Right Ascension | 19h49m11.2s | |
| Sun Declination | -21°04'21.2" | |
| Sun Semi-Diameter | 16'15.5" | |
| Sun Equatorial Horizontal Parallax | 08.9" | |
| Moon Right Ascension | 19h49m29.1s | |
| Moon Declination | -21°18'36.9" | |
| Moon Semi-Diameter | 14'53.1" | |
| Moon Equatorial Horizontal Parallax | 0°54'37.7" | |
| ΔT | 57.6 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.