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 18:19 (PDT), 43° above your southern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 18:49, 43° above your southern horizon. It will continue to be observable until around 23:33, when it sinks below 7° above your western horizon.

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
26 Oct 201418:0819:3916°south-west
27 Oct 201418:0420:2524°south-west
28 Oct 201418:0321:2031°south-west
29 Oct 201418:0322:1736°south
30 Oct 201418:0323:1840°south
31 Oct 201418:0300:2442°south
01 Nov 201418:0201:2741°south-east
02 Nov 201417:5801:3437°south-east
03 Nov 201416:5802:3731°south-east
04 Nov 201416:5803:4124°east
05 Nov 201416:5804:4816°east
06 Nov 201416:5805:51east

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 370,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 20h33m50s 13°35'S Capricornus 32'12"

The coordinates above are given in J2000.0.

The sky on 30 October 2014
Sunrise
07:03
Sunset
18:03
Twilight ends
19:27
Twilight begins
05:43

7-day old moon
Waxing Gibbous

55%

7 days old

Planets
Rise Culm. Set
Mercury 05:36 11:25 17:13
Venus 07:12 12:40 18:07
Moon 13:12 18:42 00:24
Mars 11:34 16:27 21:21
Jupiter 01:03 07:46 14:30
Saturn 08:24 13:42 19:00
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

30 Oct 2014  –  Moon at First Quarter
06 Nov 2014  –  Full Moon
14 Nov 2014  –  Moon at Last Quarter
22 Nov 2014  –  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