As you celebrate our unusually warm Halloween trick-or-treating with your little ones or passing out candy, there’s also a treat for astronomy lovers.

Halloween was rooted in the holiday Samhain, a pagan holiday originating from Celtic tradition. It marked the most important day of the middle of the Autumnal Equinox and the Winter Solstice.

During Samhain, Celts believed that the barrier between worlds could be dropped, so they dressed as monsters as to not be kidnapped, and left out offerings for them.

This makes Halloween an astronomical holiday!

Oct. 31 marks the halfway point between the Autumnal Equinox and the Winter Solstice, meaning each night grows a little longer as we inch toward the colder months. It’s a “cross-quarter day,” which means the day falls between equinoxes and solstices.

There are actually eight seasonal subdivisions every year — the March and September equinoxes, and the June and December solstices. This creates four cross-quarter days: Feb. 2, May 1, Aug. 1, and Oct. 31, the darkest of all of those days in the Northern Hemisphere.

While the true cross-quarter day is Nov. 7, the date for Halloween has been set for tradition.

And for all you stargazers out there, if those clouds clear out enough Thursday night in the D.C. area, you might see some bright planets in the night sky.

After sunset on “Astroween,” brilliant Venus greets our view low in the Southwest … you can’t miss it. Mercury is to the lower right but very low on the horizon. High in the South, yellowish Saturn gleams.

At 9 p.m. in the East, low on the horizon, you will see another bright “star,” the brightest in the sky. This is the planet Jupiter.