Glossary
Solmanac marks twenty-six moments in each Earth and Sun year. Ten have traditional names. Sixteen are new, because the equation of time and Earth’s distance from the Sun have moments that never had names.
The pairs differ by family on purpose, so each family reads differently: Great and Lesser for the sundial’s peaks, Major and Minor for the length of the day, seasons for Evensun, and compass directions for Echosun.
The standard moments
The four turning points of the seasons and the two ends of Earth’s orbit. These are the moments every almanac lists, with their usual names.
- March Equinox
- The spring (vernal) equinox in the Northern Hemisphere and the autumn equinox in the Southern.
- June Solstice
- The summer solstice in the Northern Hemisphere and the winter solstice in the Southern.
- September Equinox
- The autumn (fall) equinox in the Northern Hemisphere and the spring equinox in the Southern.
- December Solstice
- The winter solstice in the Northern Hemisphere and the summer solstice in the Southern.
- Perihelion
- The day Earth comes closest to the Sun.
- Aphelion
- The day Earth is farthest from the Sun.
Cross-quarter days
Halfway between each solstice and equinox. Like the solstices and equinoxes, they are named for their month, so the names hold in both hemispheres. Each sits behind a Gaelic festival, Imbolc, Beltane, Lughnasadh and Samhain, traditionally kept on fixed dates (Feb 1, May 1, Aug 1, Nov 1); the astronomical moment, when the Sun is exactly halfway, falls a few days later. The same four instants are the East Asian solar terms that open each season: Lichun, Lixia, Liqiu and Lidong.
- February Cross-Quarter
- Halfway between a solstice and an equinox: the astronomical moment behind Imbolc.
- May Cross-Quarter
- Halfway between a solstice and an equinox: the astronomical moment behind Beltane.
- August Cross-Quarter
- Halfway between a solstice and an equinox: the astronomical moment behind Lughnasadh.
- November Cross-Quarter
- Halfway between a solstice and an equinox: the astronomical moment behind Samhain.
Midreach
Midreach: Earth is exactly 1 AU from the Sun, close to midway between its nearest and farthest. Outward and Inward give the direction. The astronomical unit has been fixed since 2012 at exactly 149,597,870.7 km.
- Outward Midreach
- The day Earth is exactly 1 AU from the Sun, close to halfway between its nearest and farthest.
- Inward Midreach
- The day Earth is exactly 1 AU from the Sun, close to halfway between its nearest and farthest.
Earlysun and Latesun
A sundial and a clock disagree through the year by up to about a quarter of an hour. The gap is called the equation of time. It peaks four times a year, twice with the sundial ahead and twice behind. On each peak the solar day, noon to noon, is exactly 24 hours long. Great and Lesser tell the bigger peak from the smaller one.
- Great Earlysun
- The day the sundial runs furthest ahead of the clock.
- Lesser Earlysun
- The sundial's smaller peak ahead of the clock.
- Great Latesun
- The day the sundial runs furthest behind the clock.
- Lesser Latesun
- The sundial's smaller peak behind the clock.
Evensun
The four days a year when the sundial and the clock agree. The season words follow the traditional calendar, in which the solstices fall at midsummer and midwinter: Vernal (spring), Estival (summer), Autumnal and Hibernal (winter). They are assigned by which way the gap is turning and their order in the year, never by calendar month, so the autumn crossing keeps its name in years when it lands on August 31.
- Vernal Evensun
- A day the sundial and the clock agree exactly.
- Estival Evensun
- A day the sundial and the clock agree exactly.
- Autumnal Evensun
- A day the sundial and the clock agree exactly.
- Hibernal Evensun
- A day the sundial and the clock agree exactly.
Longsol and Shortsol
The solar day, from one noon to the next, is not always 24 hours. It runs up to about 30 seconds long in late December and up to about 21 seconds short in mid-September. “Sol” keeps these apart from daylight, which is a different thing. Major and Minor tell the bigger peak from the smaller one.
- Major Longsol
- The longest solar day of the year, noon to noon.
- Minor Longsol
- The second peak in the length of the solar day.
- Major Shortsol
- The shortest solar day of the year, noon to noon.
- Minor Shortsol
- The second dip in the length of the solar day.
Echosun
Echosun: one of the two days a year when the noon Sun returns to a spot it held months before, or will hold months later, where the analemma crosses itself. Northbound and Southbound give the direction. The two Echosuns share the same declination and the same equation of time, about four and a half months apart.
- Northbound Echosun
- The noon Sun stands where it will stand again months later, heading north now.
- Southbound Echosun
- The noon Sun stands where it stood months earlier, heading south now.