Mon Jul 1, 2024 CONSTELLATIONS VS. ASTERISMS
Today there are 88 official constellations. Now in the ancient world of the Mediterranean and Middle East, there were less than sixty constellations, owing partly to a lack of knowledge of stars to the south that were never seen from those latitudes. There are (and were) a great deal more unofficial star patterns, called asterisms. In order to be a constellation, everybody has to agree that that’s what it is. An asterism is more personal, and usually a lot easier to see or imagine. So the Great Bear, Ursa Major, includes the stars of the Big Dipper (what we call it here in America,) or the Plough (England,) or the Chariot (ancient Rome.) Cygnus the Swan becomes the Northern Cross, Scorpius becomes the Fish Hook, and Sagittarius the Archer looks like the crude outline of a teapot. When you first start to trace out the constellations, these asterisms will help make the more complex patterns easier to learn.
Tue Jul 2, 2024 MOON AND JUPITER IN THE PREDAWN SKY
Tomorrow morning just before sunrise, you should be able to see the moon alongside of the planet Jupiter, low near the eastern horizon. Both are in conjunction, a term that describes a close alignment of two celestial objects. Of course, Jupiter is much farther away than the moon, but to our eyes they appear to be close together. Jupiter will appear as a bright, starlike object slightly to the south of the moon, which is now in its waning crescent phase. If skies are clear, you should be able to see the dark part of the moon dimly lit by re-reflected earthshine, something that folks call, “the new moon in the old moons arms.” And with a good pair of binoculars you can see some of the rough features of the moon. Aim those binoculars at Jupiter, and you may able to see some of its moons, looking like tiny stars on either side of the planet’s disc!
Wed Jul 3, 2024 VEGA IN THE EAST – VULTUR CADENS
This evening, look toward the east. There’s a bright star over there – its name is Vega, and it’s the fifth brightest star in the night sky. Vega is from an old Arabic word meaning, “falling, (or “swooping,) eagle (or vulture)”. Vega is part of an ancient star pattern known as vultur cadens, which also means, “falling vulture,” although the official constellation here is Lyra, the Harp. On star charts you can sometimes see it pictured as a vulture with a harp inscribed within it. Above Vega are some fainter stars which trace out a simple letter H. The H stands for Hercules, and for his sixth labor, this mythical Greek hero shot arrows at this vulture, and also at two nearby constellations, Cygnus the Swan and Aquila the eagle, driving them away from Lake Stymphalus, where they had picked up the unfortunate habit of swooping down and attacking any unsuspecting people who wandered by.
Thu Jul 4, 2024 4TH OF JULY COSMIC FIREWORKS
On the 4th of July in the year AD 1054, a bright star appeared in the eastern predawn sky. It was near the star Al Hecka, the forward horn tip of the constellation Taurus the Bull. For the next month this new star, this “nova,” was so bright that it could even be seen in the daytime! As summer drew to a close, the star faded out of sight and was seen no more. In Europe there is no written record of this star’s appearance: either no one was looking up then, or more likely, the skies were overcast throughout its appearance. But Chinese astronomers made note of this “guest star,” as they called it, and that’s how we know about it today. If you’re out before sunrise this month, aim your telescope at that part of space behind the forward horn tip of Taurus, and you’ll find the Crab nebula, the exploded remains of a supernova - cosmic fireworks from nearly a thousand years ago.
Fri Jul 5, 2024 EARTH AT APHELION
This morning at 1:06 am Eastern Daylight Time, the planet Earth reached a point in its orbit known as aphelion. The earth’s orbit is slightly elliptical, so sometimes we’re a little closer to the sun than at other times. That near point is called perihelion, and the far point is known as aphelion - that’s where we are right now. So how come we're having summer? Well, it’s summer now where we are, but winter has just begun for folks south of the equator. Temperature changes occur because our planet is tilted over a little, about 23 and a half degrees, from straight up and down. Right now, our hemisphere is leaning inward, which puts the sun higher in our sky, and causes summer; in the winter the top half of earth leans away from the sun, putting it lower in our sky, which cools things down.
