Simulated image courtesy of Tom Ruen.

Moon at First Quarter

Dominic Ford, Editor
From the Moon feed

Objects: The Moon
Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
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 19:15 (PDT), 74° above your southern horizon, as dusk fades to darkness. It will then sink towards the horizon, setting at 01:45.

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
Moon
sets at
Altitude of Moon
at sunset
Direction of Moon
at sunset
10 Mar 201617:5520:0626°west
11 Mar 201617:5421:1239°west
12 Mar 201617:5722:2051°south-west
13 Mar 201618:5700:2563°south-west
14 Mar 201618:5601:2572°south-west
15 Mar 201618:5902:2174°south
16 Mar 201618:5803:1368°south-east
17 Mar 201618:5803:5658°south-east
18 Mar 201619:0104:3948°east
19 Mar 201619:0005:1737°east
20 Mar 201619:0405:5527°east
21 Mar 201619:0305:5216°east

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 05h40m20s 18°04'N Taurus 31'35"

The coordinates above are given in J2000.0.

The sky on 15 March 2016
Sunrise
06:59
Sunset
18:59
Twilight ends
20:19
Twilight begins
05:35

6-day old moon
Waxing Gibbous

55%

6 days old

Planets
Rise Culm. Set
Mercury 06:48 12:34 18:19
Venus 06:05 11:39 17:12
Moon 12:12 19:17 02:21
Mars 00:13 05:23 10:33
Jupiter 18:11 00:31 06:50
Saturn 01:12 06:18 11:23
All times shown in PDT.

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

15 Mar 2016  –  Moon at First Quarter
23 Mar 2016  –  Full Moon
31 Mar 2016  –  Moon at Last Quarter
07 Apr 2016  –  New Moon

Image credit

Simulated image courtesy of Tom Ruen.

Share

Follow

San Diego

Latitude:
Longitude:
Timezone:

32.72°N
117.16°W
PDT

Color scheme