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Sky Watch by J. Alex Knoll

Three points to summer’s triangle

Thursday’s full moon brightens the sky from dusk till dawn. American Indians called this the sturgeon moon, as it marks the time when these great fish once began their migration and were most easily caught. Sturgeon have been plying our waters for more than 150 million years, yet today most species are endangered.     More common names for August’s full are the grain moon, the lightning moon, the green corn moon and the red moon.

Summer nights are always filled with stellar sights

A gibbous moon waxes through afternoon and evening skies this week. Friday the moon, just past first quarter, is low in the southwest after sunset, with fiery Antares, the heart of Scorpius, trailing less than 10 degrees behind.

What color will you see in Libra’s beta star?

Thursday’s new moon leaves weekend skies bereft of excess light, highlighting the backdrop of stellar lights.

There’s a lot to see in our galaxy

Venus is at its brightest in the east before dawn this week, reaching its greatest illuminated extent on the 12th, when it occupies the greatest chunk of celestial real estate as viewed from Earth. After that, the planet pulls away from us, dimming a bit but by no means losing its clear title as the brightest object in the sky other than sun and moon.

Looking for ET with Hercules

Given the scorching temperatures of late, you might be surprised to know that earth is at its farthest point from the sun this time of year, called, aphelion. On July 4, Earth reached the apex of its elliptical orbit around the sun at 94,505,851 miles. That’s about three million miles farther than at perihelion, earth’s closest point to the sun.

See if you can beat Galileo’s 40

As the sun sets this week, its latest of the year at 8:35, Saturn and Mars appear in the darkening skies, Mars high in the southwest and Saturn trailing 25 degrees at due south. Mars sets at midnight, with Saturn following 90 minutes later.     Our neighbor isn’t called the red planet for nothing: its orange hue is quite distinct and a real contrast to golden Saturn, although both shine at around first magnitude and are as bright as any star.

You’ll have to rise early and stay up late to see all five naked-eye planets

The nascent crescent moon emerges from the glow of sunset low in the west-northwest Thursday evening. Above the moon is Mercury with the Gemini twins Pollux and Castor higher still. Sunset Friday finds the waxing crescent a little higher in the west with Mercury, Pollux, and Castor farther to its right.

Look for the moon’s shadowy face on these shortest nights

The waning crescent moon heralds the coming sun in pre-dawn eastern skies through week’s end. So close to the sun’s glow, there’s more to this moon than meets the eye. While the crescent appears clearly aglow, the supposedly missing face appears as a dark notch. This is a result of earthshine, sunlight reflected off our planet that casts a shadowy glow over the rest of the moon’s visible face.

The season’s brightest star shines overhead

Look for Mars high above the southwest horizon at the feet of Leo the lion, with blue-white Regulus well to the west. Saturn is high in the south, with equally bright Spica five degrees below. Mars and Saturn both shine at first magnitude, as bright as a typical star, but Mars fades noticeably over the month. Right now they are more than 30 degrees apart, but through summer they draw closer together until Mars passes the ringed planet in mid-August.

You won’t have another chance

This is the final countdown to one of the rarest sights in the heavens, a transit of Venus. Venus crosses the face of the sun in eight-year pairings, each cycle separated by 115 years. The last transit of Venus was in 2004. The next is Tuesday, June 5. After that, there won’t be another until December of 2117!