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 Fairfield , it will become visible around 18:15 (EDT) as the dusk sky fades, 76° above your southern horizon. It will then sink towards the horizon, setting at 01:51.

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.

Seasonal variation

Although the Moon passes first quarter every month, it is more favourably placed in the early evening sky at some times of year than others.

The first quarter moon appears high in the evening sky around the spring equinox, but much lower towards the horizon around the autumn equinox.

This is because it always lies close to a line across the sky called the ecliptic. This marks the flat plane in space in which all of the planets circle the Sun. It is the line through the zodiacal constellations that the Sun follows through the year.

The altitude at which the Moon appears above the horizon at sunset depends how steeply the line of the ecliptic is inclined to the horizon. If the plane of the ecliptic meet the horizon at a very shallow angle, the Moon will rise or set along a line which is almost parallel to the horizon, and a large separation from the Sun along this line would still only correspond to a very low altitude in the sky.

The inclination of the ecliptic plane to the horizon at Fairfield varies between 72° (sunset at the spring equinox) and 25° (sunset at the autumn equinox). On March 14, the ecliptic is inclined at 72° to the western sunset horizon, as shown by the yellow line in the planetarium view above, meaning that on this occasion the Moon is favourably placed for viewing from Fairfield.

The Moon's position

At the moment it reaches first quarter, the Moon's distance from the Earth will be 382,000 km. Its celestial coordinates will be as follows:

Object Right Ascension Declination Constellation Angular Size
The Moon 05h32m40s +28°16' Taurus 31'13"

The coordinates above are given in J2000.0.

The sky on 14 April 2021
Sunrise
06:16
Sunset
19:32
Twilight ends
21:12
Twilight begins
04:36

2-day old moon
Waxing Crescent

6%

2 days old

Planets
Rise Culm. Set
Mercury 06:07 12:32 18:57
Venus 06:32 13:12 19:51
Moon 07:36 14:48 22:12
Mars 09:19 16:57 00:36
Jupiter 03:59 09:13 14:27
Saturn 03:24 08:23 13:21
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

14 Mar 1989  –  Moon at First Quarter
22 Mar 1989  –  Full Moon
22 Mar 1989  –  The Moon at apogee
25 Mar 1989  –  The Moon at aphelion

Image credit

Simulated image courtesy of Tom Ruen.

Share

Follow

Fairfield

Latitude:
Longitude:
Timezone:

41.14°N
73.26°W
EDT

Color scheme