© John Buonomo, North Billerica, MA.

Total 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 total eclipse of the Moon, though it will not be visible from Ashburn since the Moon will be beneath the horizon at the time.

The Moon will be totally eclipsed from 14:41 until 15:54, and there will be a partial eclipse visible from 13:30 until 17:06 (all times given in Ashburn time).

Eclipses of the Moon are easy to watch with the unaided eye. A modest pair of binoculars will give a superb view of the Moon's surface, but are not required. Unlike solar eclipses, lunar eclipses are entirely safe to look at without the need to look through any kind of filter.

They 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. The circular shadow cast by the Earth appears as a bite taken out of the Moon during its partial phases.

When the Moon's disk lies entirely in shadow, it often takes on a spectacular reddy-brown color, as some of the Sun's red light is bent around the edge of the Earth's globe by its atmosphere.

Sequence of events

The eclipse will begin at 12:21, when the Moon first enters a region of the Earth's shadow called the penumbra. In this outer part of the Earth's shadow, an observer on the Moon would see the Sun partially obscuring the Sun's disk, but not completely covering it. As a result the Moon's brightness will begin to dim, as it is less strongly illuminated by the Sun, but it remains illuminated.

At 13:30, the edge of the Moon's disk will enter the Earth's umbra. This is the region of space in which an observer on the Moon's surface would see the Earth completely obscuring the whole of the Sun's disk, and would find themselves suddenly thrust into darkness.

As an increasing fraction of the Moon's face creeps into the Earth's umbra, it will appear to have a growing bite taken out of it. We will see our planet's circular shadow sweep across the face of the Moon.

Eventually the Moon will pass entirely within the Earth's umbra at 14:41, and the total eclipse will begin.

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

Local
time
UTC
12:2116:21Moon begins to enter the Earth's penumbra
13:3017:30Moon begins to enters the Earth's umbra. Partial eclipse begins.
14:4118:41Moon fully within Earth's umbra. Total eclipse begins.
15:1819:18Midpoint of eclipse
15:5419:54Moon begins to leave the Earth's umbra. Total eclipse ends.
17:0621:06Moon fully outside the Earth's umbra. Partial eclipse ends.
18:1422:14Moon leaves the Earth's penumbra
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 October 17 will be visible.

Map of where the eclipse of October 1986 will be visible.
Map of where the eclipse of October 1986 will be visible. Click here to expand.

Further information

This eclipse is a member of Saros series 136. The exact position of the Moon at the midpoint of the eclipse is as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 01h29m +09°42' Pisces 30'24"

The coordinates above are given in J2000.0.

The sky on 22 May 2018
Sunrise
05:50
Sunset
20:20
Twilight ends
22:11
Twilight begins
03:59

7-day old moon
Waxing Gibbous

54%

7 days old

Planets
Rise Culm. Set
Mercury 05:09 12:02 18:54
Venus 07:51 15:24 22:57
Moon 13:32 20:07 02:05
Mars 00:42 05:29 10:16
Jupiter 18:52 00:08 05:19
Saturn 22:55 03:44 08:30
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_198610.png

Related news

10 Oct 1986, 09:29 EDT  –  Moon at First Quarter
17 Oct 1986, 15:23 EDT  –  Full Moon
25 Oct 1986, 18:27 EDT  –  Moon at Last Quarter
02 Nov 1986, 01:03 EST  –  New Moon

Image credit

© John Buonomo, North Billerica, MA.

Ashburn

Latitude:
Longitude:
Timezone:

39.04°N
77.49°W
EDT

Color scheme