Celebrate Fall Astronomy Day This Weekend

What is Astronomy Day?

Doug Berger, whereas president of the Astronomical Association of Northern California on the time, began Astronomy Day in 1973 with the objective of bringing consideration to the night time sky. Astronomy Day occurs each spring and fall on a Saturday near the first-quarter Moon. This month, the Moon reaches first quarter on Wednesday, October thirteenth (October twelfth for U.S. time zones).

Whether you’ve gotten a telescope, binoculars, or choose to look at with solely your unaided eye, this can be a nice likelihood to move out and see some wonderful issues within the night time sky this weekend.

Star events, the place folks carry their tools and observe collectively, are a terrific way to spend the night time. These occasions are an inspiring expertise for anybody, together with freshmen who’re simply beginning to study astronomy.

Unfortunately, COVID-19 continues to be making issues tough, and many people can’t get to occasions simply. Instead, how about having a digital star get together? Talk to some buddies or with an area astronomy membership, chat on-line, and revel in all issues astronomical this weekend.

Here are some things to get you began, particularly for those who’re new to the passion.

The Sun

It is Astronomy Day isn’t it? Why ought to the whole lot occur at night time? So, just a few occasions in the course of the day, word the place the Sun is. That path the Sun travels throughout the sky known as the ecliptic, which is able to come in useful later.

IMPORTANT: Please, no telescopes or binoculars for this. You may severely injury your eyes. Do not stare on the Sun, lenses or not.

The Moon and Venus

In the dimming autumn night, let’s search for our nearest celestial neighbor: the Moon. On Saturday after sundown, in deepening twilight, we’ll see a younger, waxing crescent Moon, about midway between new and first quarter, simply above the gorgeous gleam of the planet Venus. As the pair glide towards the horizon, let’s see if we are able to spot earthshine, the daylight that bounced off Earth, off the Moon, and again to our eyes. Earthshine seems a dim glow on the Moon’s unlit facet, and it’s best to see in the course of the Moon’s crescent phases. Maybe we are able to additionally catch a few of the Moon’s options hiding within the shadows there. The pair will set about two hours after sundown, so linger right here for awhile; it’ll be value it.

Planets along the ecliptic
Follow the ecliptic from the Moon and Venus towards Saturn and Jupiter on October ninth.

Saturn and Jupiter

Remember after we had been watching the Sun’s motion throughout the sky and used it to think about the ecliptic? After catching up with the Moon and Venus, comply with that very same imaginary line again towards the east throughout the southern sky. The subsequent vivid object we’ll come to is the planet Saturn.

I received’t lie, Saturn’s a bit robust. It’s not as vivid as we’d count on it to be; in spite of everything, its mild has traveled nearly 2 billion miles to get to our eyes! Still, I all the time love how understated and refined it’s with the bare eye. Binoculars possible received’t allow you to see the rings, however their presence makes the planet seem a bit stretched out and egg-shaped. With a telescope, these rings come into clearer view. With optical help, you would possibly even have the ability to see its big moon, Titan, showing as a close-by star. (You can double-check utilizing our interactive online tool.)

A bit farther to the east, we’ll discover unmistakable Jupiter. It’s the third-brightest object within the night time sky (after the Moon and Venus), and it’s been positively beautiful not too long ago. With our binoculars, we are able to spot its 4 planet-size “Galilean” moons: Io, Europa, Ganymede, and Callisto. Those tiny dots are every very roughly the scale of Mercury.

Jupiter and its Galilean moons
A glimpse of Jupiter and the Galilean moons

The Pleiades

As the night time goes on, we’ll see the Pleiades open star cluster (Messier 45) rise. The Pleiades, which appears to be like like a tiny dipper, however isn’t the well-known Little Dipper, is 444 light-years from us. This makes it one of many closest open star clusters to Earth. With good imaginative and prescient and sufficiently darkish skies, we’d have the ability to see six or seven stars with the bare eye. Through binoculars, although, it’s positively jaw-dropping, with numerous stars spilled throughout the sky. We normally consider this cluster as a wintertime object, however right here it’s in early October: a sneak preview of fine issues to come back.

Pleiades on the sky
The Pleiades within the late night, once they’re excessive within the jap sky, on October ninth.
Stellarium, with additions by the writer

The Andromeda Galaxy

This one’s a little bit of a problem for freshmen. The Andromeda Galaxy (Messier 31) is the closest giant spiral galaxy, and in October, it’s well-placed for straightforward recognizing in mid-evening. While it’s potential to see M31 underneath very darkish and clear skies, most of us want binoculars or a telescope to seek out it.

There are two straightforward methods to get to it. First, face northeast and discover the constellation Cassiopeia. This month, its stars sit just like the quantity “3” within the northeast sky. Then scan the sky about 15 levels towards the fitting or higher proper. (Extend your fist and stick out your index and pinkie fingers in a “hang loose” signal, and it’ll be that far towards the fitting of Cassiopeia for those who’re within the Northern Hemisphere ).

Or you’ll be able to star-hop with a telescope or binoculars. Start by discovering Mirach, which is the second within the line of three stars extending northeast from northeastern nook of the Great Square of Pegasus. From Mirach, hop towards the northwest to Mu Andromedae, then to Nu Andromedae (see diagram beneath), and begin scanning the sky close by.

Either way, you’ll know if you see it as a result of the galaxy nearly appears to be like like an enormous thumbprint on the sky. This is a superb ability to choose up as a result of as soon as we discover it, we’ll know precisely the place to look subsequent time, after which we are able to inform everybody the place they will see 2.5 million-year-old mild, too.

How to find M31
Use the stars of the Cassiopeia and Andromeda constellations to seek out the Andromeda Galaxy
Stellarium, with additions from the writer

These are only a few issues we are able to see this weekend. What else ought to we search for? I hope you’ll head out and have a terrific Astronomy Day, everybody! Leave a remark and let me know the way it goes!


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