Simulated image courtesy of Tom Ruen.

Moon at First Quarter

Dominic Ford, Editor
From the Moon feed

Objects: The Moon
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The sky at

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

From San Diego , it will become visible around 17:37 (PDT), 78° above your southern horizon, as dusk fades to darkness. It will then sink towards the horizon, setting at 00:37.

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 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 San Diego local time.

Date Sun
sets at
sets at
Altitude of Moon
at sunset
Direction of Moon
at sunset
29 Jan 202817:2020:1934°south-west
30 Jan 202817:2121:1344°south-west
31 Jan 202817:2122:0755°south-west
01 Feb 202817:2123:0565°south-west
02 Feb 202817:2100:0574°south
03 Feb 202817:2101:0877°south-east
04 Feb 202817:2502:1072°east
05 Feb 202817:2603:1461°east
06 Feb 202817:2604:1549°east
07 Feb 202817:2605:0535°east
08 Feb 202817:3005:5123°east
09 Feb 202817:3006:33east

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 389,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 02h39m50s 20°59'N Aries 30'40"

The coordinates above are given in J2000.0.

The sky on 03 February 2028
Twilight ends
Twilight begins

8-day old moon
Waxing Gibbous


8 days old

Rise Culm. Set
Mercury 06:21 11:47 17:13
Venus 08:45 14:41 20:37
Moon 10:37 17:51 01:08
Mars 07:19 12:44 18:08
Jupiter 20:36 02:46 08:56
Saturn 10:01 16:20 22:39
All times shown in PST.


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

03 Feb 2028  –  Moon at First Quarter
10 Feb 2028  –  Full Moon
17 Feb 2028  –  Moon at Last Quarter
25 Feb 2028  –  New Moon

Image credit

Simulated image courtesy of Tom Ruen.



San Diego



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