| Penumbral eclipse | |||||||||
 The Moon's hourly motion shown right to left | |||||||||
| Date | September 6, 1998 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Gamma | −1.1058 | ||||||||
| Magnitude | −0.1544 | ||||||||
| Saros cycle | 147 (8 of 71) | ||||||||
| Penumbral | 227 minutes, 46 seconds | ||||||||
| |||||||||
A penumbrallunar eclipse occurred at the Moon’sdescending node of orbit on Sunday, September 6, 1998,[1] with an umbralmagnitude of −0.1544. A lunar eclipse occurs when theMoon moves into theEarth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into the Earth's penumbra. Unlike asolar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on thenight side of Earth. Occurring about 1.8 days beforeperigee (on September 8, 1998, at 7:00 UTC), the Moon's apparent diameter was larger.[2]
The eclipse was completely visible overnortheast Asia, much ofAustralia, westernNorth America and thePacific Ocean, seen rising overeast andsoutheast Asia and western Australia and setting over much of North andSouth America.[3]
 |
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]
| Parameter | Value |
|---|---|
| Penumbral Magnitude | 0.81217 |
| Umbral Magnitude | −0.15437 |
| Gamma | −1.10579 |
| Sun Right Ascension | 10h59m47.2s |
| Sun Declination | +06°25'26.3" |
| Sun Semi-Diameter | 15'52.1" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 23h01m06.1s |
| Moon Declination | -07°29'07.2" |
| Moon Semi-Diameter | 16'25.0" |
| Moon Equatorial Horizontal Parallax | 1°00'15.2" |
| ΔT | 63.3 s |
This eclipse is part of aneclipse 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 afortnight. The first and last eclipse in this sequence is separated by onesynodic month.
| August 8 Descending node (full moon) | August 22 Ascending node (new moon) | September 6 Descending node (full moon) |
|---|---|---|
 |  | |
| Penumbral lunar eclipse Lunar Saros 109 | Annular solar eclipse Solar Saros 135 | Penumbral lunar eclipse Lunar Saros 147 |
This eclipse is a member of asemester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[5]
The penumbral lunar eclipse onAugust 8, 1998 occurs in the next lunar year eclipse set.
| Lunar eclipse series sets from 1995 to 1998 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Ascending node | Descending node | |||||||
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma | |
| 112 | 1995 Apr 15 | Partial | −0.9594 | 117 | 1995 Oct 08 | Penumbral | 1.1179 | |
122 | 1996 Apr 04 | Total | −0.2534 | 127 | 1996 Sep 27 | Total | 0.3426 | |
132 | 1997 Mar 24 | Partial | 0.4899 | 137 | 1997 Sep 16 | Total | −0.3768 | |
| 142 | 1998 Mar 13 | Penumbral | 1.1964 | 147 | 1998 Sep 06 | Penumbral | −1.1058 | |
This eclipse is a part ofSaros series 147, repeating every 18 years, 11 days, and containing 70 events. The series started with a penumbral lunar eclipse on July 2, 1890. It contains partial eclipses fromSeptember 28, 2034 through May 27, 2431; total eclipses from June 6, 2449 through October 5, 2647; and a second set of partial eclipses from October 16, 2665 through May 1, 2990. The series ends at member 70 as a penumbral eclipse on July 28, 3145.
The longest duration of totality will be produced by member 37 at 105 minutes, 18 seconds on August 1, 2539. All eclipses in this series occur at the Moon’sdescending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series will occur on2539 Aug 01, lasting 105 minutes, 18 seconds.[7] | Penumbral | Partial | Total | Central |
| 1890 Jul 02 | 2034 Sep 28 | 2449 Jun 06 | 2485 Jun 28 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 2593 Sep 02 | 2647 Oct 05 | 2990 May 01 | 3134 Jul 28 | |
Eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
| Series members 1–18 occur between 1890 and 2200: | |||||
|---|---|---|---|---|---|
| 1 | 2 | 3 | |||
| 1890 Jul 02 | 1908 Jul 13 | 1926 Jul 25 | |||
 |  |  |  | ||
| 4 | 5 | 6 | |||
| 1944 Aug 04 | 1962 Aug 15 | 1980 Aug 26 | |||
 |  |  |  |  |  |
| 7 | 8 | 9 | |||
| 1998 Sep 06 | 2016 Sep 16 | 2034 Sep 28 | |||
| |  |  | |  |
| 10 | 11 | 12 | |||
| 2052 Oct 08 | 2070 Oct 19 | 2088 Oct 30 | |||
 |  |  |  | ||
| 13 | 14 | 15 | |||
| 2106 Nov 11 | 2124 Nov 21 | 2142 Dec 03 | |||
| 16 | 17 | 18 | |||
| 2160 Dec 13 | 2178 Dec 24 | 2197 Jan 04 | |||
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1801 and 2096 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1802 Mar 19 (Saros 129) | 1813 Feb 15 (Saros 130) | 1824 Jan 16 (Saros 131) | 1834 Dec 16 (Saros 132) | 1845 Nov 14 (Saros 133) | |||||
| 1856 Oct 13 (Saros 134) | 1867 Sep 14 (Saros 135) | 1878 Aug 13 (Saros 136) | 1889 Jul 12 (Saros 137) | 1900 Jun 13 (Saros 138) | |||||
| 1911 May 13 (Saros 139) | 1922 Apr 11 (Saros 140) | 1933 Mar 12 (Saros 141) | 1944 Feb 09 (Saros 142) | 1955 Jan 08 (Saros 143) | |||||
 |  |  |  |  |  |  |  |  |  |
| 1965 Dec 08 (Saros 144) | 1976 Nov 06 (Saros 145) | 1987 Oct 07 (Saros 146) | 1998 Sep 06 (Saros 147) | 2009 Aug 06 (Saros 148) | |||||
 |  |  |  |  |  | | |  |  |
| 2020 Jul 05 (Saros 149) | 2031 Jun 05 (Saros 150) | ||||||||
 |  |  |  | ||||||
| 2096 Nov 29 (Saros 156) | |||||||||
This eclipse is a part of the long periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1801 and 2200 | |||||
|---|---|---|---|---|---|
| 1825 Jan 04 (Saros 141) | 1853 Dec 15 (Saros 142) | 1882 Nov 25 (Saros 143) | |||
| 1911 Nov 06 (Saros 144) | 1940 Oct 16 (Saros 145) | 1969 Sep 25 (Saros 146) | |||
 |  |  |  |  |  |
| 1998 Sep 06 (Saros 147) | 2027 Aug 17 (Saros 148) | 2056 Jul 26 (Saros 149) | |||
| |  |  |  |  |
| 2085 Jul 07 (Saros 150) | 2114 Jun 18 (Saros 151) | 2143 May 28 (Saros 152) | |||
| 2172 May 08 (Saros 153) | |||||
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (ahalf saros).[8] This lunar eclipse is related to two partial solar eclipses ofSolar Saros 154.
| August 31, 1989 | September 11, 2007 |
|---|---|
 |  |
_(cropped).jpg)
