Loaf Mass and the Dog Days of Summer

Thursday, August 18, 2011

Well, I was so excited about the Nebraska Star Party that I missed Lammas Day. What is that you ask? Well, why don't I tell you.

In the old calendar, and I am talking about the middle ages here. Lammas Day, or "Loaf Mass Day" was generally the first day of August. In Britain and Ireland it was a day for paying rents and bringing the first fruits of the harvest, usually wheat ground into flour and baked into special loaves of bread, to the church as an offering of thanksgiving for a bountiful harvest.

This bread was then used as the host in a special mass of thanksgiving.

But Lammas Day is also something else, something else astronomical.

It is a "Cross-quarter Day." A day that is about halfway between the summer solstice and the autumnal equinox. In other words, summer is half over and we are moving into autumn.

We can see it in the sky. The constellations of spring, Leo, Virgo, and Bootes are fading and sinking below the western horizon while the constellations of summer, specifically the Summer Triangle, are high overhead.

Let's not forget that autumn is coming. That means the stars of the fall are starting to rise in the east. Now we can look at about an hour after local sunset for The Great Square of Pegasus, Perseus, the Hero, and Aquarius, The Water-bearer.

Other cross-quarter days are Candlemass, (In the colonies it was transformed into Ground Hogs Day), Beltain or May Day, and Samhain, better known in the modern version as Halloween.

All marked a point roughly halfway between the major seasonal dates of winter, spring, summer, and autumn.

Incidentally, in case you were wondering, autumn starts on Sept. 23. That is the date of the autumnal equinox when the sun crosses the celestial equator moving from north to south giving us, for at least a few days, equal day and night.

Another astronomical event we might want to look at, "The Dog Days of Summer." This was supposed to be the hottest part of the summer when even a dog wouldn't go outside.

It is usually put between July 11 and August 11. This is the time when Sirius, the brightest star is Canis Major, the Big Dog, or The Dog Star, the brightest star in the evening sky is rising with the sun.

The ancient Greeks and Romans reasoned that Sirius was adding its heat to the sun and that is why it was so hot. Well, we know better today, Sirius does not add its heat to the sun.

But, if you have noticed, in the last few days the daytime temperatures have been a little cooler.

SKY WATCH: Third-quarter moon, Sunday, Aug. 21. Saturn is rapidly sinking in the west after sunset. Jupiter is rapidly rising in the east after sunset. At midnight, Aug. 20 the moon and Jupiter meet for a midnight showing in the east. During the next two nights the moon plays tag with the Pleiades star cluster first appearing on one and then the other on consecutive days. If you are an early morning person, be outside in your favorite dark-sky place at 3 a.m. Wednesday morning, Aug. 24, with binoculars in hand to look for the moon and M35 to do a nice cozy up.

NEXT WEEK: More astronomical blathering.

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