A supermoon, though it won't be much bigger than other full moons, will be seen in the Butler County sky Monday night.

This Monday, there will be a full moon shining over Butler. It’s not just any full moon though, but a spectacular supermoon, the first of three fantastic supermoons this year!

Does it seem that I’m really excited about the supermoon? Honestly, no, I’m not. I’m being sarcastic. I think this moniker is a bit overplayed. I know it all depends on how you define the word super, but many of my stargazing colleagues, as well as yours truly, aren’t exactly on board with the supermoon hype.

Like it or not, hype has become a staple of the media these days. The term “supermoon” fits in nicely with the hype-happy folks.

Before I’m accused of being a curmudgeon and total killjoy, the full moon Monday night will indeed be a little bigger in the sky than average, but not all that much bigger and dramatic.

For many folks, unless they’re told we have a supermoon, they probably wouldn’t know the difference. That’s certainly not meant as a put down because honestly, the moon isn’t all that much bigger.

The full moon’s size in the sky depends on how close or far our lunar companion is from Earth. Since the moon’s 27.3-day orbit around the Earth is slightly elliptical, the moon has a minimum distance from Earth called perigee and a maximum distance from Earth called apogee. Meanwhile, the cycle of the moon’s phases (from new moon to new moon) is a little longer at 29.5 days. Because these cycles are not in sync, the full moon’s distance from Earth varies.

When the moon is at perigee, it’s only around 221,000 miles away. At apogee, the moon is about 252,000 miles from Earth. For a full moon to be considered a supermoon, it has to be at the right place at the right time.

The full moon has to be, by definition, within 90 percent of the perigee distance. This requirement for a supermoon, and the term itself, doesn’t originate from an astronomer but rather an astrologer. A supermoon is only 7% larger than an average full moon and only 14 percent brighter. It’s not that big of a deal. A full moon at apogee is considered a “wimpy moon” by some folks, but it’s not all that smaller than average.

Quite often, when there’s a supermoon, you’ll see video on TV newscasts of a tremendously large supermoon rising just above the horizon. They’ll say something like, “Look at that big supermoon.”

Again, I hope I’m not coming off as a curmudgeon, but any full moon will appear large when it’s rising or setting near the horizon. That’s an optical illusion. When a rising full moon gets a little higher in the sky it appears smaller, but it just isn’t. You can prove this to yourself. When a full moon is first rising, hold one of your fingers at arm’s length against the moon and compare the width of the moon with the width of your finger. Later in the evening, when the moon seems smaller and higher in the sky, hold that same finger at arm’s length against the moon, and I can guarantee it won’t be any smaller.

I hope you don’t think that I’m too tough on the media and others about the supermoon, but I want to set the record straight as an amateur astronomer.

No matter what label someone tacks on to a full moon, it’s lovely at any size!

By the way, that bright star to the lower right of the moon on Monday night is Spica, over 250 light-years away and over 14 times the diameter of our sun.

Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Contact him at mikewlynch@comcast.net.