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 Cambridge , it will become visible around 18:41 (EDT) as the dusk sky fades, 72° above your south-western horizon. It will then sink towards the horizon, setting at 01:52.

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.

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 378,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 07h23m30s 27°22'N Gemini 31'32"

The coordinates above are given in J2000.0.

The sky on 06 May 2021
Sunrise
05:30
Sunset
19:50
Twilight ends
21:42
Twilight begins
03:38

24-day old moon
Waning Crescent

17%

24 days old

Planets
Rise Culm. Set
Mercury 06:19 13:54 21:29
Venus 06:06 13:24 20:42
Moon 03:41 09:10 14:52
Mars 08:37 16:20 00:03
Jupiter 02:38 07:54 13:10
Saturn 01:53 06:49 11:46
All times shown in EDT.

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

09 Apr 2117  –  Moon at First Quarter
15 Apr 2117  –  The Moon at perigee
16 Apr 2117  –  Full Moon
18 Apr 2117  –  The Moon at aphelion

Image credit

Simulated image courtesy of Tom Ruen.

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Cambridge

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Longitude:
Timezone:

42.38°N
71.11°W
EDT

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