Yesterday (as this post goes live) was Old Lady-Day, once a significant day in the English agricultural calendar. And today (April 6th), a new tax year begins in the UK. These dates are not unrelated to each other, and are also linked to the Christian Feast of the Annunciation, which commemorates the Biblical event depicted in the Leonardo painting at the head of this post—the arrival of the Angel Gabriel to inform the Virgin Mary that she was to conceive a miraculous child.
In the northern hemisphere, the Harvest Moon falls on 1 October in 2020, which is what provokes this post. The Harvest Moon is defined as the full moon that occurs closest to the autumnal equinox, which fell on 22 September (in the northern hemisphere, in 2020). You can find many lists of “names of the … Continue reading Harvest Moon
The year 2020, newly begun as this post is published, is a leap year. I’ve written before about leap years, and how the occasional leap day added to the end of February keeps our calendar year synchronized with the seasons. For more on that topic, see my posts about February 30th and the Equinox. But … Continue reading Leap Seconds
I’m posting this on March 20, the date of the first equinox of the year. In the northern hemisphere, we call it the spring or vernal equinox, because it marks the start of astronomical spring in northern latitudes. (The meteorological seasons follow the calendar months, so meteorological spring started on March 1.) Of course, for … Continue reading Equinox
The Date or Calendar Line is a modification of the line of the 180th meridian, and is drawn so as to include islands of any one group, etc, on the same side of the line. When crossing this line on a westerly (true) course, the date must be advance one day; when crossing it … Continue reading Territories That Crossed The Date Line: Part 2 – 1900 To Present
Constrained by extreme necessity, we decided on touching at the Cape Verde Islands, and on Wednesday the 9th of July, we touched at one of those islands named St. James’s. […] In order to see whether we had kept an exact account of the days, we charged those who went ashore to ask what day … Continue reading Territories That Crossed The Date Line: Part 1 – Up To 1900
Here’s the problem: the tropical year, the time it takes the Earth to go through a complete cycle of seasons, is 365.2422 days long (to four-decimal accuracy). If every calendar year were 365 days long, then the missing 0.2422 days would add up from year to year, each year starting a little earlier relative to … Continue reading February 30th