Simulated image courtesy of Tom Ruen.

Moon at Last Quarter

Dominic Ford, Editor
From the Moon feed

Objects: The Moon
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The sky at

The Moon will pass last quarter phase, rising in the middle of the night and appearing prominent in the pre-dawn sky.

From San Diego, it will be visible from soon after it rises, at 00:50, until soon before it sets at 10:51.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

At this time in its monthly cycle of phases, it appears almost exactly half illuminated.

The Moon orbits the Earth once every four weeks, causing its phases to cycle through new moon, first quarter, full moon, last quarter, and back to new moon once every 29.5 days.

As it progresses through this cycle, it is visible at different times of day. At last quarter, it rises in the middle of the night and appears high in the sky by dawn. It sets at around lunchtime. More information about the Moon's phases is available here.

Observing the Moon at last quarter

Over coming days, the Moon will rise later each day, so that it is visible for less time before sunrise and rises less far above the eastern horizon before dawn. By the time it reaches new moon, it will rise at around dawn and set at around dusk, making it visible only during the daytime.

Its daily progress is charted below, with all times are given in San Diego local time.

Date Sun
rises at
Moon
rises at
Altitude of Moon
at sunrise
Direction of Moon
at sunrise
01 Mar 202106:1518:2114°west
02 Mar 202106:1419:2921°west
03 Mar 202106:1220:3727°south-west
04 Mar 202106:1121:4531°south-west
05 Mar 202106:1022:5434°south-west
06 Mar 202106:0900:0334°south
07 Mar 202106:0801:1133°south
08 Mar 202106:0602:1529°south
09 Mar 202106:0503:1325°south-east
10 Mar 202106:0404:0319°south-east
11 Mar 202106:0304:4713°south-east
12 Mar 202106:0105:25south-east

The exact moment of last quarter

The exact moment of last quarter is defined as the time when the Moon's ecliptic longitude is exactly 90° away from the Sun's ecliptic longitude, as observed from the center of the Earth. However, the Moon does not appear in any way special at this instant in time, and a last quarter moon can be observed at any time in the pre-dawn sky.

At the moment it reaches last quarter, the Moon's distance from the Earth will be 372,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 16h56m30s 22°40'S Ophiuchus 32'05"

The coordinates above are given in J2000.0.

The sky on 5 Mar 2021

The sky on 5 March 2021
Sunrise
06:09
Sunset
17:48
Twilight ends
19:10
Twilight begins
04:47

22-day old moon
Waning Crescent

44%

22 days old

Planets
Rise Culm. Set
Mercury 04:54 10:15 15:36
Venus 06:02 11:41 17:21
Moon 00:03 05:20 10:33
Mars 09:43 16:45 23:47
Jupiter 04:54 10:13 15:33
Saturn 04:25 09:38 14:51
All times shown in PST.

Source

The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

05 Mar 2021  –  Moon at Last Quarter
13 Mar 2021  –  New Moon
21 Mar 2021  –  Moon at First Quarter
28 Mar 2021  –  Full Moon

Image credit

Simulated image courtesy of Tom Ruen.

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San Diego

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32.72°N
117.16°W
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