Moon at First Quarter

Dominic Ford, Editor
From the Moon feed


Objects: The Moon

The Moon will pass first quarter phase, appearing prominent in the evening sky and setting in the middle of the night.

From Cambridge , it will be visible from soon after it rises, at 12:09, until soon before it sets at 23:23.

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 first quarter, it appears high in the sky at sunset before sinking towards the horizon and setting in the middle of the night. More information about the Moon's phases is available here.

Observing the Moon at first quarter

Over coming days, the Moon will set later each day, becoming visible for more of the night. Within a few days, it will not make it very far above the eastern horizon before nightfall. By the time it reaches full phase, it will be visible for much of the night, rising at around dusk and setting at around dawn.

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

Date Sun
sets at
Moon
sets at
Altitude of Moon
at sunset
Direction of Moon
at sunset
03 Dec 203516:1118:4120°south-west
04 Dec 203516:1119:3325°south-west
05 Dec 203516:1020:2729°south
06 Dec 203516:1021:2432°south
07 Dec 203516:1022:2234°south
08 Dec 203516:1023:2235°south-east
09 Dec 203516:1000:2334°south-east
10 Dec 203516:1001:2731°south-east
11 Dec 203516:1002:3427°east
12 Dec 203516:1003:4321°east
13 Dec 203516:1004:5414°east
14 Dec 203516:1006:06east

The exact moment of first quarter

The exact moment of first 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 first quarter moon can be observed at any time in the evening sky.

At the moment it reaches first quarter, the Moon's distance from the Earth will be 394,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 23h07m50s 7°08'S Aquarius 30'17"

The coordinates above are given in J2000.0.

The sky on 22 Nov 2024

The sky on 22 November 2024
Sunrise
06:41
Sunset
16:16
Twilight ends
17:55
Twilight begins
05:02


Waning Gibbous

51%

21 days old

Planets
Rise Culm. Set
Mercury 08:36 12:57 17:19
Venus 10:09 14:31 18:53
Moon 22:03 05:23 12:29
Mars 20:40 04:06 11:33
Jupiter 17:14 00:45 08:16
Saturn 13:02 18:32 00:03
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

07 Dec 2035  –  Moon at First Quarter
14 Dec 2035  –  Full Moon
21 Dec 2035  –  Moon at Last Quarter
29 Dec 2035  –  New Moon

Image credit

Simulated image courtesy of Tom Ruen.

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