The Moon will pass close to the Sun and become lost in the its glare for a few days.
The Moon's orbital motion carries it around the Earth once every four weeks, and as a result its phases cycle from new moon, through first quarter, full moon and last quarter, back to new moon once every 29.5 days.
This motion also means that the Moon travels more than 12° across the sky from one night to the next, causing it to rise and set nearly an hour later each day. More information about the Moon's phases is available here.
At new moon, the Earth, Moon and Sun all lie in a roughly straight line, with the Moon in the middle, appearing in front of the Sun's glare. In this configuration, we see almost exactly the opposite half of the Moon to that which is illuminated by the Sun, making it doubly unobservable because the side we see is unilluminated.
Observing the Moon in the days after new moon
Over coming days, the Moon will become visible in the late afternoon and dusk sky as a waxing crescent which sets soon after the Sun. By first quarter, in a week's time, it will be visible until around midnight.
Its daily progress is charted below, with all times are given in Cambridge local time.
| Date | Sun sets at |
Moon sets at |
Altitude of Moon at sunset |
Direction of Moon at sunset |
| 09 Sep 2018 | 19:05 | 19:19 | 2° | west |
| 10 Sep 2018 | 19:03 | 19:52 | 8° | west |
| 11 Sep 2018 | 19:01 | 20:23 | 14° | west |
| 12 Sep 2018 | 18:59 | 20:54 | 19° | south-west |
| 13 Sep 2018 | 18:58 | 21:26 | 23° | south-west |
| 14 Sep 2018 | 18:56 | 22:00 | 25° | south-west |
| 15 Sep 2018 | 18:54 | 22:37 | 26° | south |
The exact moment of new moon
At the moment of closest approach, it will pass within 3°26' of the Sun, in the constellation Leo. The celestial coordinates of the Sun and Moon will be:
| Object | Right Ascension | Declination | Constellation | Angular Size |
| The Moon | 11h16m30s | 8°23'N | Leo | 32'50" |
| Sun (centre) | 11h11m | 5°13'N | Leo | 31'45" |
The coordinates above are given in J2000.0.
The sky on 9 Sep 2018
| The sky on 9 September 2018 | ||||||||||||||||||||||||||||||||||
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0% 29 days old |
All times shown in EDT.
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Warning
Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.
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 Sep 2018 | – New Moon |
| 16 Sep 2018 | – Moon at First Quarter |
| 24 Sep 2018 | – Full Moon |
| 02 Oct 2018 | – Moon at Last Quarter |
Image credit
Simulated image courtesy of Tom Ruen.