August 2016 lunar eclipse
Template:Short description Template:Infobox lunar eclipse A penumbral lunar eclipse occurred at the Moon’s descending node of orbit on Thursday, August 18, 2016,[1] with an umbral magnitude of −0.9925. A lunar eclipse occurs when the Moon moves into the Earth'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 a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. Occurring about 3.4 days before perigee (on August 21, 2016, at 21:20 UTC), the Moon's apparent diameter was larger.[2]
The HM National Almanac Office's online canon of eclipses lists this event as the last eclipse on Saros Series 109,[3] while NASA lists August 8, 1998 as the last eclipse of the series, and has this event missing the shadow.[4]
This eclipse grazed the northern boundary of the Earth's penumbral shadow. The event lasted 33 minutes and 36 seconds, beginning at 9:25 UTC and ending at 9:59. This produced a maximum penumbral magnitude of 0.0166.Template:Sfn Eclipses of such small magnitudes are visually imperceptible; a penumbral magnitude of approximately 0.6 is required for even skilled observers to detect.Template:Sfn
Background
The Earth's penumbral shadow is larger than would be expected from simple geometry, a phenomenon first observed by Philippe de La Hire in 1707. The precise amount of enlargement varies over time for reasons which are not fully understood, but likely involve the amount of dust in certain layers of the Earth's atmosphere.Template:Sfn Various eclipse almanacs have used different assumptions about the magnitude of this effect, resulting in disagreement about the predicted duration of lunar eclipses or, in the case of penumbral eclipses of very short duration, whether the eclipse will occur at all.Template:Sfn
In 1989, NASA published a lunar eclipse almanac that predicted a short penumbral lunar eclipse to occur on 18 August 2016. However, the French almanac Connaissance des Temps used more conservative assumptions about the size of the Earth's shadow and did not predict an eclipse to occur at all.Template:Sfn The Bureau des Longitudes in France continued to refine their lunar eclipse models; NASA's 2009 edition of its lunar eclipse almanac was based on their values,Template:Sfn which effectively reclassified nine eclipses between 1801 and 2300 as non-events, including the one in August 2016.Template:EfnTemplate:Sfn
Some resources, including the HM Nautical Almanac Office's online canon of eclipses, continued to list the 18 August 2016 event. Despite not appearing in NASA's printed lists of eclipses since the 2009 revision, AccuWeather reported the upcoming eclipse and projected this was the final member of Lunar Saros 109.[5]
Visibility
The eclipse was completely visible over Australia, North and South America, and Antarctica, seen rising over western Australia and northeast Asia and setting over eastern North and South America.[6]
| File:Lunar eclipse from moon-2016Aug18.png | File:Lunar eclipse chart close-2016Aug18.png Hourly motion shown right to left |
Eclipse season
Script error: No such module "Labelled list hatnote". 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. The first and last eclipse in this sequence is separated by one synodic month.
| August 18 Descending node (full moon) |
September 1 Ascending node (new moon) |
September 16 Descending node (full moon) |
|---|---|---|
| File:Lunar eclipse chart close-2016Aug18.png | File:SE2016Sep01A.png | File:Lunar eclipse chart close-2016Sep16.png |
| Penumbral lunar eclipse Lunar Saros 109 |
Annular solar eclipse Solar Saros 135 |
Penumbral lunar eclipse Lunar Saros 147 |
Related eclipses
Eclipses in 2016
- A total solar eclipse on March 9.
- A penumbral lunar eclipse on March 23.
- A penumbral lunar eclipse on August 18.
- An annular solar eclipse on September 1.
- A penumbral lunar eclipse on September 16.
Metonic
- Followed by: Lunar eclipse of June 5, 2020
Tzolkinex
- Preceded by: Lunar eclipse of July 7, 2009
Tritos
- Followed by: Lunar eclipse of July 18, 2027
Lunar Saros 109
- Preceded by: Lunar eclipse of August 8, 1998
Inex
- Preceded by: Lunar eclipse of April 14, 1987
- Followed by: Lunar eclipse of March 3, 2045
Triad
- Followed by: Lunar eclipse of June 20, 2103
Lunar eclipses of 2016–2020
Template:Lunar eclipse set 2016-2020
Saros 109
Template:Lunar Saros series 109
Inex series
Template:Inex eclipse set info
| Series members between 1801 and 2200 | |||||
|---|---|---|---|---|---|
| 1814 Jan 06 (Saros 102) |
1842 Dec 17 (Saros 103) |
||||
| 2016 Aug 18 (Saros 109) |
|||||
| File:Lunar eclipse chart close-2016Aug18.png | File:Lunar eclipse from moon-2016Aug18.png | ||||
| 2074 Jul 08 (Saros 111) |
2103 Jun 20 (Saros 112) |
2132 May 30 (Saros 113) | |||
| 2161 May 09 (Saros 114) |
2190 Apr 20 (Saros 115) | ||||
See also
- List of lunar eclipses
- List of 21st-century lunar eclipses
- October 2042 lunar eclipse
- July 2027 lunar eclipse
Notes
References
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Bibliography
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