Sky-watchers will be in for a treat this weekend as a full moon and the fourth and the final lunar eclipse of the year takes place. Lunar eclipses only occur during a full moon, and this one, known as a penumbral lunar eclipse, will take place as the moon enters Earth’s outer shadow.
It will take place during the evening of Sunday 29 November through the early hours of the next day, and of course clear skies will be a great help in admiring the phenomenon. November's full moon is known as a frosty moon, beaver moon, oak moon and mourning moon, which dates back to when Native American tribes tracked the changing seasons by the lunar months rather than the solar calendar and attributed names to them that were appropriate for the time of year.
Full moons happen every 29.5 days, and occur when the sun lines up opposite the moon and illuminates its surface. The penultimate full moon of the year will see a large part of it appearing to lose its brightness as it passes through the outer part of Earth's shadow, known as its penumbra. Watchers will note a gradual darkening of 83% of the full moon, and the peak of the penumbral lunar eclipse will be seen at 9.42am UT, 4.42am EDT and 1.42am PDT on 30 November. The full moon will appear on the horizon at moonrise the evening before, at a time that depends on your location.
Experts reckon that the penumbral lunar eclipse is more of a fascinating phenomenon than a spectacular one, due to the darkening of the moon, but it will still be worth observing.