Harvest Moon tonight!

Guest Columnist

By André Duvall

For the next several nights, pending clear weather, we have the opportunity to witness one of my favorite annual events of the evening and night skies: the rising of the Harvest Moon, which is the first full moon occurring after the Autumnal Equinox (which fell a week ago today). Tonight (September 29), the moon will rise in its “Full” phase. The exact moment of the full moon is 11:19 Eastern Time, although the moon will for all practical purposes appear full all night long.

    During the majority of the year, full moons rise about 50 minutes later on successive nights, creating a period of relative darkness between sunset and moonrise. In contrast, the Harvest Moon rises about 30 minutes later on successive nights, resulting in sustained light as the glow of twilight gradually relinquishes to the beams of moonlight for several nights in a row. In earlier times, before farm equipment had lighting, this unbroken source of natural light allowed farmers to work longer hours in the fields to reap the harvest, hence the term “Harvest Moon.” Although the moon is no longer technically “full” after the first night, a very large percentage of the moon is still visible. Because full moons rise near the time of sunset, the Harvest Moon creates the effect of a full moon rising for several evenings.
    The Harvest Moon usually occurs in September, although it can occur in October, as it did last year. A similar phenomenon occurs to a lesser degree at the next lunar cycle, which is known in moon folklore as the “Hunter’s Moon,” since hunters were given extra light after sunset for a few nights in a row.

If you have some free time on any of the next few evenings, try to find a location above the tree-line, where you have an unobstructed view of the eastern horizon.
    Tonight, the full moon rises at 6:38 p.m. EDT. The sun sets at 7:05 p.m.
    Tomorrow, the moon rises at 7:10 p.m., and the sun sets at 7:04 p.m.
    On Monday, the moon rises at 7:43 p.m., and the sun sets at 7:02 p.m. (These times are based on my location in the Piedmont Triad of North Carolina, and will vary based on your global position. See http://aa.usno.navy.mil/data/docs/RS_OneDay.php for complete Sun and Moon data for one day in your location.)
    One of the joys of watching the Harvest Moon is observing the gradual shifting of colors as it rises. It starts out as a deep red as it first peeps over the horizon, shifting to ever-lighter shades of orange as it clears the horizon, 

transitioning to a creamy peach color as it resembles a round lamp suspended in the lower sky, and finally brightening to shades of white as it ascends to greater heights. Each night, the effect of these color changes can have a slightly different emotional effect, because the sun will have set a different time in relation to the moon’s rising. The reds and oranges take on different characters against a darker sky on later nights than they do on the first night.
    I find the moments before the moon appears to be quite suspenseful. As I do not know exactly where the top curve of the sphere is going to appear over the horizon, I eagerly scan the eastern horizon for the first sliver of red. On the first night, it can be very difficult to spot the first few moments of the moon’s arrival; due to the light from the sun, it can appear quite dim for a few minutes. When I do spot the moon, sometimes it has already been in the sky for several minutes; the moment I spot it often gives me goose bumps. I think to myself, how has it been sitting there for this long without me seeing it?! On later nights, it is much easier to spot the moon right as it rises.
    Happy moon watching!
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Copyright © 2012 by André Duvall