This Friday’s full moon shall be a somewhat special one in that it should carry the title of “Harvest Moon” for those living within the Northern Hemisphere.
The moon officially will turn full when it reaches a spot within the sky opposite (180-degrees) to the sun. This moment will occur on Friday (Sept. 29) at 09:57 Greenwich Time (or within the Eastern Time zone, just prior to moonset at 5:57 a.m.).
It also seems that this full moon is the one which comes closest to the September equinox. In 2023, this circumstance comes a bit later than usual. While most traditionally associate the Harvest Moon with the month of September, there are some years where it falls within the month of October. Between 1970 and 2050, for example, there are 18 years when the Harvest Moon is available in October. The last time was in 2020 and next time shall be in 2025.
The Harvest Moon can occur as early as Sept. 8 (because it did in 2014) or as late as Oct. 7 (as it should in 2025). This Harvest Moon can even mark the last of 4 so-called “supermoons” in a row.
Supermoons are full moons that occur at or near perigee — when the moon is closest to Earth in its orbit — and offer a fantastic time for seasoned lunar skywatchers because the moon can appear barely larger and brighter. Although, that luminosity and size difference is tough to identify for the casual observer. There have been 4 supermoons that happened in a row since July, with two of them in August (the latter was a rare Blue Super Moon) resulting in this month’s finale.
Related: Last supermoon of 2023 rises this week. Don’t miss the Harvest Moon shine with 3 shiny planets
Many may imagine that the Harvest Moon stays within the night sky longer than any of the opposite full moons we see through the yr, but that is actually not the case. That individual circumstance is reserved for the total moon closest to the Winter Solstice (which this yr will come on Dec. 26).
Moonrise timings
What sets the Harvest Full Moon other than other full moons is that farmers on the climax of the present harvest season can work late into the night since the moon’s light becomes so shiny. It also rises concerning the time the sun sets, but more importantly, at the moment of yr, as an alternative of rising 50 or so minutes later each evening (as usual) the moon seems to rise at nearly the identical time every night.
For instance, in Latest York City, moonrise on Sep. 28 is at 6:35 p.m. EDT. On Sep. twenty ninth, moonrise is at 7:00 p.m. EDT and on Sep. 30, it’s 7:25 p.m. EDT. So in comparison with the traditional rise time of fifty minutes later per night, the time of the Harvest Moon moonrise comes 25 minutes later. More specifically, that is about one-half the traditional delay..
Tonight-to-night difference is biggest in additional southerly locations. For instance: Cocoa Beach, Florida, situated near latitude 28.4-degrees N, sees moonrise come a median of 35 minutes later. Meanwhile, at Calgary, Alberta, Canada situated at latitude 51.0-degrees N, the typical difference is only quarter-hour later.
The explanation for this seasonal circumstance is that the moon appears to maneuver along the ecliptic. At the moment of yr, when rising, the ecliptic makes its smallest angle with respect to the horizon for those living within the Northern Hemisphere.
Moonrise oddities at different latitudes
In contrast, for those living within the Southern Hemisphere, the ecliptic at the moment of yr appears to face almost perpendicular (at nearly a right angle) to the eastern horizon. As such, the difference for the time of moonrise exceeds the typical of fifty minutes per night. In Melbourne, Australia (37.8-degrees S), for example, the night-to-night difference amounts to 75 minutes.
Interestingly, for individuals who live near the Arctic Circle — 66.7-degrees N, the moon does indeed appear to rise concerning the same time each night through the Harvest Moon’s reign. And for individuals who live even farther to the north, a paradox appears — the moon appears to rise earlier!
At Resolute Bay in Nunavut, Canada (latitude 74.7-degrees N), for example, the times of moonrise on Sep. 28, 29 and 30 shall be, respectively, 7:24 p.m. CDT, 6:31 p.m. CDT and 5:25 p.m. CDT. So, from Resolute Bay, the moon will appear to rise (on average) about 60 minutes each night.
Nighttime harvesting is gone… however the moon stays
Recall that earlier, I had mentioned that our late-September moon may very well be utilized by farmers to work late into the night — in the event that they cared to, that’s. Indeed, 100 years or so ago, when most harvesting was done solely by hand, these evenings of early fall moonlight were a godsend to harried farmers hurrying to get their late crops in before the winter season. They might cut, shock and husk corn by moonlight, right in the sector in the event that they cared to. They may also usher in the last stores after dinner and without much need of a lantern.
But those days are all but gone. Farmers now use choppers and corn pickers drawn by tractors to make the job go faster; even a late harvest is now a daylight job.
Thankfully, nonetheless, the Harvest Moon stays.
These next several evenings, step outside and luxuriate in the view; clouds notwithstanding, it should shine on magnificently within the east, brightly illuminating our early autumn evening sky.