Are there "CORRECT" dates for the CROSSQUARTER DAYS?
"I'm ok with the dates shown for the Quarter Days (solstices and equinoxes),
but what's the deal with your dates for the CROSSQUARTERS?"
The crossquarter values (XQ) are derived from a precise halving of the whole-time extending between each adjacent equinox and solstice.
It is understood that
there are -other- methods sometimes suggested for deriving the XQ
values, such as halving the Sun's apparent range of declination (the
range of the Sun's position above or below the celestial equator
through the year), or by ancient observational methods like watching
the sunrise or sunset's progression along a local horizon, or
measuring its elevation at local noon, etc. For XQ values calculated
by degrees of the Earth’s progress along its orbital path
around the Sun, go
BTW, There should be no reason for debate over the dates of the actual solstices and equinoxes…
those are formally recognized and observable astronomical phenomena. On the other hand, the four familiar* dates only roughly midway between them commonly referred-to as "crossquarters" are not and have never been part of astronomical calendar-keeping (at least not in the annals of recorded history).
* The 4 crossquarters and their "familiar" dates (eve/day's) from the surviving Folk Traditions (SFT):
Imbolc (Feb.1-2), Beltaine (Apr.30-May 1), Lughnasa (July 31-Aug.1), and Samhain (Oct.31-Nov.1)
The names just given for those are the Irish SFT versions.
- ERIC CANALI
For more information, or a clarification, send your request to the following electronic mail address: < FAQ@planetarium.cc >. Editor’s Note: This astronomically-related question was answered by a very experienced amateur astronomer, who also works as a part-time Tour Guide at the Allegheny Observatory in Pittsburgh. Allegheny Observatory provides public tours two nights a week from April through October; pre-registration is necessary, but the tours are free-of-charge. For many years, Eric G. Canali was Floor Manager for the original Buhl Planetarium and Institute of Popular Science in Pittsburgh. He also was a long-time member of the Amateur Astronomers' Association of Pittsburgh and is Founder of the South Hills Backyard Astronomers. Return to FAQ Page Return to History of The Buhl Planetarium and Institute of Popular Science, Pittsburgh