Moon at Last Quarter

Dominic Ford, Editor
From the Moon feed


Objects: The Moon

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

From Fairfield, it will be visible from soon after it rises, at 00:25, until soon before it sets at 11:13.

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 Fairfield local time.

Date Sun
rises at
Moon
rises at
Altitude of Moon
at sunrise
Direction of Moon
at sunrise
26 Jan 203507:0719:2617°west
27 Jan 203507:0620:3223°west
28 Jan 203507:0521:3528°south-west
29 Jan 203507:0422:3531°south-west
30 Jan 203507:0323:3434°south-west
31 Jan 203507:0200:3234°south
01 Feb 203507:0101:2833°south
02 Feb 203507:0002:2331°south
03 Feb 203506:5903:1627°south
04 Feb 203506:5804:0723°south-east
05 Feb 203506:5704:5517°south-east
06 Feb 203506:5605:3912°south-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 401,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 14h38m30s 10°55'S Libra 29'43"

The coordinates above are given in J2000.0.

The sky on 31 Jan 2035

The sky on 31 January 2035
Sunrise
07:02
Sunset
17:06
Twilight ends
18:41
Twilight begins
05:27


Waning Crescent

45%

22 days old

Planets
Rise Culm. Set
Mercury 06:11 11:12 16:14
Venus 04:10 08:55 13:41
Moon 00:32 05:58 11:20
Mars 03:15 07:56 12:36
Jupiter 09:34 15:47 22:00
Saturn 16:00 23:19 06:39
All times shown in EST.

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

31 Jan 2035  –  Moon at Last Quarter
08 Feb 2035  –  New Moon
15 Feb 2035  –  Moon at First Quarter
22 Feb 2035  –  Full Moon

Image credit

Simulated image courtesy of Tom Ruen.

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