None available.

Penumbral lunar eclipse

Dominic Ford, Editor
From the Eclipses feed

Time:       Altitude: °      Azimuth: °

A simulation of how the eclipse will appear from Ashburn.

The outer grey circle is the Earth's penumbra, and the inner black circle is the umbra. Any part of the Moon which passes within the black circle will be unilluminated, while any part within the grey circle will appear less bright than usual.




There will be a penumbral eclipse of the Moon, visible from Ashburn in the southern sky. The Moon will lie 66° above the horizon at the moment of greatest eclipse.

The eclipse will last from 23:00 until 02:57, and maximum eclipse will occur at 00:59 (all times given in Ashburn time).

A penumbral eclipse

Like other lunar eclipses, penumbral eclipses occur whenever the Earth passes between the Moon and Sun, such that it obscures the Sun's light and casts a shadow onto the Moon's surface. But unlike other kinds of eclipses, they are extremely subtle events to observe.

In a penumbral eclipse the Moon passes through an outer region of the Earth's shadow called the penumbra. This is the outer part of the Earth's shadow, in which the Earth appears to cover part of the Sun's disk, but not all of it (see diagram below). As a result, the Moon's brightness will begin to dim, as it is less strongly illuminated by the Sun, but the whole of the Sun's disk will remain illuminated to some degree.

Although the Moon's light dims considerably during a penumbral eclipse, this is only perceptible to those with very astute vision, or in carefully controlled photographs.

On this occasion 88% of the Moon's face will pass within the Earth's penumbra at the moment of greatest eclipse, and so a modest reduction in the Moon's brightness may be perceptible.

The geometry of a lunar eclipse
The geometry of a lunar eclipse. Within the penumbra, the Earth covers some fraction of the Sun's disk, but not all of it. In the umbra, the Earth covers the entirity of the Sun's disk. Any parts of the Moon's surface that lie within the Earth's umbra will appear unilluminated. Image courtesy of F. Sogumo.

Visibility of the eclipse

Eclipses of the Moon are visible anywhere where the Moon is above the horizon at the time. Since the geometry of lunar eclipses requires that the Moon is directly opposite the Sun in the sky, the Moon can be seen above the horizon anywhere where the Sun is beneath the horizon. The map below shows where the eclipse of January 30 will be visible.

Map of where the eclipse of January 1991 will be visible.
Map of where the eclipse of January 1991 will be visible. Click here to expand.

The table below lists the times when each part of the eclipse will begin and end.

Local
time
UTC
23:0004:00Moon begins to enter the Earth's penumbra
00:5905:59Greatest eclipse
02:5707:57Moon leaves the Earth's penumbra

This eclipse is a member of Saros series 143. The exact position of the Moon at the moment of greatest eclipse is as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 08h48m +16°42' Cancer 32'44"

The coordinates above are given in J2000.0.

The sky on 27 May 2018
Sunrise
05:47
Sunset
20:24
Twilight ends
22:18
Twilight begins
03:53

12-day old moon
Waxing Gibbous

95%

12 days old

Planets
Rise Culm. Set
Mercury 05:16 12:20 19:25
Venus 07:59 15:31 23:03
Moon 18:42 00:03 04:50
Mars 00:29 05:17 10:04
Jupiter 18:30 23:42 04:57
Saturn 22:34 03:24 08:09
All times shown in EDT.

Source

Espanak, F., & Meeus, J., Five Millennium Canon of Lunar Eclipses: -1999 to +3000, NASA Technical Publication TP-2009-214172 (2009)

You may embed the map above in your own website. It is licensed under the Creative Commons Attribution 3.0 Unported license, which allows you to copy and/or modify it, so long as you credit In-The-Sky.org.

You can download it from:
https://in-the-sky.org/news/eclipses/lunar_199101.png

Related news

23 Jan 1991, 09:23 EST  –  Moon at First Quarter
30 Jan 1991, 01:11 EST  –  Full Moon
06 Feb 1991, 08:53 EST  –  Moon at Last Quarter
14 Feb 1991, 12:33 EST  –  New Moon

Image credit

None available.

Ashburn

Latitude:
Longitude:
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39.04°N
77.49°W
EDT

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