cross-quarter days

[nibot]

I've long thought it a little counterintuitive that seasons are said to begin and end on the equinoxes and solstices—after all, wouldn't you naïvely expect the longest day of the year, the summer solstice, to be the middle of summer (midsommar!) and not its beginning? (I would say that the seasons and the length of the days are 90 degrees out of phase... )

I learned on the radio today that the days midway between solstices and equinoxes are called cross-quarter days, and in many cultures do mark the boundaries of the seasons.

Today is November's cross-quarter day, marking the middle of astronomical autumn, and the first day of traditional winter.

Comments

Winter Solstice

[jqmold.livejournal.com]

Another counterintuitive phenomenon: You would think that the year's ealiest sunset and it's latest sunrise would both occur on the shortest day of the year. Not so. Look at an almanac. The earliest sunset is around Dcember 6th (an auspicious date otherwise)and the latest sunrise is around January 7th. It has to do with the equation of time. ie the difference between mean solar time and apparent solar time - or , in other words, the error of a sundial resulting from the Earth not orbitting the Sun at a uniform rate. We are whipping around the Sun much faster at perigee (December) than at apogee.
While you have the almanac out, look at the times of sunrise/sunset for dates near the equinox. You'll find that the day of 12 hour day & 12 hour night occurs several days before the spring equinox. The causes (there are two) are left as an exercise for the student.

Re: Winter Solstice

[furzicle.livejournal.com]

Yes, but will you reveal the answer key before too long???!!!