The last day of October marks the mid-point between autumnal equinox and winter solstice, one of four cross-quarter days in the passage of the earth around the sun. The day has been recognized for millennia, celebrated as Samhein, The Day of the Dead and All Hallow’s Eve, or Halloween.

Sunset finds Venus ablaze low in the southwest before setting by 8pm. There is no brighter planet or star, and so close to the horizon Venus can pulse and shimmer as its light is distorted by our atmosphere. Traveling close to the sun, Venus appears for at most a few hours either after sunset or before dawn. This led early civilizations to believe that the evening star and the morning star were two distinct objects. The ancient Greeks called the morning Venus Phosphoros and the evening apparition Hesperos.

As the sun sets Friday, the full Hunter’s Moon rises, shining all night long and reaching its highest around midnight. Like last month’s Harvest Moon, the Hunter’s Moon travels its shallowest arc along the ecliptic, rising far to the north of due east and setting far to the south. Rising so much farther to the north than other months, the Hunter’s Moon reappears just 30 minutes later from night to night, as opposed to 50 minutes normally. The effect of this is several consecutive nights bathed in moonlight from near sunset to sunrise.

Saturday, October 12, is International Observe the Moon Night, a global celebration of earth’s only natural satellite. InOMN is overseen by “scientists, educators, and moon enthusiasts [who] believe in the inspirational power of the moon — a celestial body that has influenced human lives since the dawn of time.”

Friday marks new moon. You might think that the new moon is lost behind the sun. But the moon is roughly 250,000 miles from earth, while the sun is more than 90 million miles away. So the moon can never be behind the sun. Rather, new moon is right in front of us, directly between earth and the sun, invisible in the blinding glare.     This makes for dark night skies much of the week, allowing you to spot more dim and distant celestial objects.

If you’ve been outside after dark the past few days, you’ve likely noticed the full-appearing moon. While Thursday the 19th marks the true full phase, September’s Harvest Moon fills the sky for several days at a time. The full moon closest to Autumnal Equinox, the Harvest Moon gets its name from the role it played historically in providing light for farmers to bring in the last of the season’s crops.

Saturn and Venus have been fixtures of the early evening sky, and come Friday, the two are within half a dozen degrees of one another. By Tuesday they are barely three degrees apart low in the west-southwest immediately after sunset. Venus is so bright you may spot her while the sky is still lit. Saturn pops into view to the upper left of Venus. Both planets sink beneath the horizon within an hour of the sun, but over the coming weeks, Venus holds steady, while Saturn disappears from view.

Twilight Thursday and Friday reveals dazzling Venus low in the west with much fainter Spica less than two degrees below. Look for Saturn a dozen degrees above and to the left of this pairing.     In the half-hour following sunset Saturday, an ever-so-thin nascent crescent moon joins the party, hovering just above the western horizon to the lower right of Venus and Spica. To spot it, you will need good timing, an unimpeded view and maybe even binoculars.

The waning crescent moon graces our pre-dawn skies, appearing lower and lower in the east throughout the week. The morning of the 31st, look for it near bright Jupiter. The following morning you’ll find the moon midway between a triangle of bright stars: the Gemini twins Castor and Pollux and Procyon in Canis Minor. Monday before dawn, the moon lights the way to ruddy Mars, above and to the left in the gathering morning twilight.

For kids heading back to school, summer has truly gone to the dogs. But neither that nor your canine companion panting on the cold basement floor is why the hottest days of the year are referred to as the Dog Days of summer. The answer shines in the heavens in the form of a star more than 81⁄2 light years away.