Saturday night is the spookiest night of the year. Not just because it’s Halloween… but also because it’s a Halloween with a full moon. This sort of thing happens about once every 18 or 19 years. Less rare, but still pretty rare is the fact that it’s also a Blue moon, meaning it’s the second full moon in the calendar month. We get a blue moon about every 2.5 years. The last one we saw was March of 2018.

But because Halloween is the last day in a 31-day month, and the lunar cycle is 29-and-a-half days, every Halloween full moon is a blue moon.

And even though the full moon officially happens one night out of the month, it’ll appear full all weekend. On Friday night, it’ll rise just before 7pm. Saturday night, trick-or-treaters will be able to see it just above the horizon around 7:15 . On Sunday night, it gets confusing because it’ll rise again before 7pm--yet another trick... the end of Daylight Saving Time.

Of course, the full moon through binoculars or a telescope can be fun, but if you’re looking for more treats, there are plenty of other bright targets to appreciate this weekend as well. In the evenings, bright orange Mars will be high to the southeast, while Jupiter and Saturn will be setting toward the southwest. Grab a telescope--any telescope--even good binoculars, and you’re likely to see Jupiter’s four largest moons, and the rings around Saturn.

So, if we’re lucky enough to have clear skies on Halloween, you’ll have plenty to scream about.