A Blue Moon—May's Flower Moon—Is Coming Next Month

Matt Cardy/Getty Images
Matt Cardy/Getty Images

Exactly how often is "once in a blue moon"? According to NASA, the celestial occurrence isn't especially rare: A blue moon happens about once every 2.5 years. The next blue moon will appear the night of May 18, 2019, and because the event marks the first full moon of May, it will also be a flower moon.

What Is a Blue Moon?

Instead of describing color, like a blood moon, the term blue moon is reserved for an additional full moon that appears within a certain window of time. There are two types of blue moons: monthly blue moons and seasonal blue moons. A monthly blue moon, the more popular of the two definitions, is the second full moon that occurs in a single calendar month. This usage is fairly recent, and likely originated from an error printed in a 1946 issue of Sky and Telescope magazine.

A seasonal blue moon is the older meaning, and it describes the third moon in a season that has four full moons. Each season—winter, spring, summer, and fall—typically sees three full moons, and in the rare event there are four, the third is singled out as the anomaly. This is sometimes the preferred definition of astronomy-minded people because it's based on natural equinoxes and solstices rather than the Gregorian calendar.

When to See the Blue Flower Moon

The full moon set to light up the night sky in May will be a seasonal blue moon. The time of year it occurs—May—makes it a flower moon. The first full moon of each month has a special name: A worm moon is a full moon in April, and a wolf moon is a full moon in January.

To catch 2019's blue flower moon, look up the night of May 18. The Moon will be at its fullest when it's precisely at 180° ecliptic longitude opposite the Sun—which occurs at 5:11 p.m. ET on May 18.

Amazon's Under-the-Radar Coupon Page Features Deals on Home Goods, Electronics, and Groceries

Stock Catalog, Flickr // CC BY 2.0
Stock Catalog, Flickr // CC BY 2.0

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Now that Prime Day is over, and with Black Friday and Cyber Monday still a few weeks away, online deals may seem harder to come by. And while it can be a hassle to scour the internet for promo codes, buy-one-get-one deals, and flash sales, Amazon actually has an extensive coupon page you might not know about that features deals to look through every day.

As pointed out by People, the coupon page breaks deals down by categories, like electronics, home & kitchen, and groceries (the coupons even work with SNAP benefits). Since most of the deals revolve around the essentials, it's easy to stock up on items like Cottonelle toilet paper, Tide Pods, Cascade dishwasher detergent, and a 50 pack of surgical masks whenever you're running low.

But the low prices don't just stop at necessities. If you’re looking for the best deal on headphones, all you have to do is go to the electronics coupon page and it will bring up a deal on these COWIN E7 PRO noise-canceling headphones, which are now $80, thanks to a $10 coupon you could have missed.

Alternatively, if you are looking for deals on specific brands, you can search for their coupons from the page. So if you've had your eye on the Homall S-Racer gaming chair, you’ll find there's currently a coupon that saves you 5 percent, thanks to a simple search.

To discover all the deals you have been missing out on, head over to the Amazon Coupons page.

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Uranus Reaches Opposition on Halloween in 2020

Christine Schmitt, Flickr // CC BY-NC-ND 2.0
Christine Schmitt, Flickr // CC BY-NC-ND 2.0

Uranus is roughly 1.75 billion miles away from Earth, which makes it difficult to spot without a telescope most nights. But on Saturday, October 31, the seventh planet from the sun will be worth looking for. Uranus reaches opposition that night, making it appear extra bright in the night sky.

What Is Uranus at Opposition?

An opposition occurs when the Earth falls perfectly between another planet and the sun. When this happens, the sun's light appears to fully illuminate the planet's surface, boosting its brightness level to the maximum.

Uranus reaches opposition on October 31 in 2020. During this event, Uranus will hit a limiting magnitude of 5.86, which is about the minimum brightness for what's visible with the naked eye.

How to Look for Uranus at Opposition

Spotting Uranus at opposition will be slightly more difficult in 2020 than in years past. The phenomenon coincides with a full moon that will make dimmer stars and planets—including Uranus—harder to see in the night sky. The planet sits in the constellation Aries, which regrettably appears close to the moon for most of the night.

Uranus should appear as a small, blue-green disc when using a telescope. Even if you have trouble spotting the seventh planet, it will still be worth checking out the night sky on October 31: Halloween this year coincides with a rare blue moon.