Post Archives: Watchers of the Skies

For live links, click to: riverhouses.org/2019-spica 😊

June is the first month of Hercules Term in the River Houses, and as the River Houses Star Calendar will tell you, our great-star-of-the-month for June is Spica, the brightest star in the constellation Virgo. Its formal designation is α Virginis — “alpha of Virgo.” Spica (in Latin) is the ear of grain — the spike — in the left hand of the harvest maiden Proserpina (Persephone in Greek).

If you want to introduce your students to Spica, you can start with some basic astronomy from your homeschool star atlas (riverhouses.org/books):

“Virgo is both a zodiacal and equatorial constellation. Spica, its brightest star, is about 30º southwest of Arcturus in Boötes [next month’s great star] and forms the southernmost point of the Diamond of Virgo. Spica has a magnitude of 1.2 and it’s the 14th of the 20 brightest stars in the sky. The autumnal equinox, where the sun crosses the celestial equator on its journey south, is located close to the star η [eta] Virginis. In the rough square formed by Denebola in Leo [the lion’s tail] and ε [epsilon], γ [gamma] and β [beta] Virginis lies the so-called ‘Field of the Nebulae’ where Herschel discovered 323 nebulae; some of these are visible in a small telescope.“ (Celestron Sky Maps, page 7)

The planisphere on the front of your star atlas will help you locate Spica, and that’s plenty for beginning students — your little lesson is done. If you want to get more advanced, the Wikipedia page on Spica is packed with additional information on everything from astrometrics to cultural history.

Spica is a blue-white giant about seven times the diameter of the sun. It has a small companion that is invisible to the eye (even with a telescope) but that can be detected spectroscopically. The Spica pair is about 250 light years distant — close in astronomical terms — and it’s also quite young: about 12.5 million years old.

Spica is very close to the ecliptic, the line followed by the moon, sun, and planets as they cross the earth’s sky, and so on rare occasions it is briefly covered by them — an event called an occultation. The last occultation of Spica by Venus occurred in the year 1783, and the next will occur in 2197.

Measurements of Spica’s position are believed to have led the ancient astronomer Hipparchus to discover the precession of the equinoxes.

Spica has given its name to a World War II cargo ship, a teenage detective in a Japanese manga series, and (of course!) the South Korean pop group Spica:

This month, why not take your homeschool students out at dusk and introduce them to this great nearby sun, and teach them its name, and so give them a new friend for life.

What stellar observations have you made in your homeschool lately? 😊

❡ Alpha and beta and gamma, oh my: Most of the principal stars within each constellation have both old vernacular names — Vega, Sirius, Arcturus, and so on — as well as more formal scientific designations. The German astronomer Johann Bayer (1572–1625) devised the formal system of star designations that is still in common use today. In Bayer’s system, the stars in each constellation, from brightest to dimmest, are assigned a lowercase letter of the Greek alphabet: α (alpha, brightest), β (beta, second brightest), γ (gamma, third brightest), δ (delta, fourth brightest), and so on. This letter designation is combined with the Latin name of the constellation in its possessive (genitive) form: Lyra becomes Lyrae (“of Lyra”), Canis Major becomes Canis Majoris (“of Canis Major”), and so on. The brightest star in the constellation Lyra (the star Vega) thus becomes α Lyrae (“alpha of Lyra”), the brightest star in Canis Major (the star Sirius) becomes α Canis Majoris (“alpha of Canis Major”), and so on, through all 24 Greek letters and all 88 constellations. How bright would you expect, say, the σ (sigma) star of Orion to be? Not very bright — it’s far down the alphabet — but σ Orionis happens to be the top star of Orion’s sword, so even though it’s not very bright it’s still notable and easy to locate on a dark night. ✨

❡ Watchers of the skies: Teaching your students to recognize the constellations is one of the simplest and most enduring gifts you can give them. The planisphere on the front of your River Houses star atlas (riverhouses.org/books) will let you dial up the northern hemisphere sky for any night of the year, and the descriptions and maps of each constellation will point out the highlights, including the names and characteristics of the brightest stars. Your general world atlas also has beautiful maps of the whole northern and southern hemisphere night skies on plates 121–122. Why not find a dark-sky spot near you this month and spend some quality homeschool time beneath the starry vault. 🌠 🔭 🌌 🌟

❡ First star I see tonight: This is one of our monthly “great star” posts featuring twelve of the brightest stars of the northern hemisphere night sky. Download and print your own copy of our River Houses Star Calendar (riverhouses.org/calendars) and follow along with us as we visit a different great star each month. 🌟

For live links, click to: riverhouses.org/2019-june-sky 😊

On the first Saturday of every month we post educational skywatching notes for the homeschool month ahead. Here’s the monthly northern hemisphere night-sky review for June 2019 from the Hubble Space Telescope’s website:

And here’s another June night-sky review, courtesy of NASA’s Jet Propulsion Laboratory in California — it features some wonderful planetary observations you and your students can make this month:

For serious homeschool skywatchers, the weekly updates from Sky & Telescope magazine provide a wealth of additional detail. Here’s the latest one:

• ➔ This Week’s Sky at a Glance, 31 May – 8 June 2019

The best stargazing nights in June will be toward the beginning and the end of the month – the moon will be full (and the dimmer stars less visible) on the 17th. As always, you can track the moon’s phases on page 357 in your River Houses almanac (riverhouses.org/books) and also at the excellent timeanddate.com website.

June is the first month of Hercules Term, the fourth of the four three-month terms that make up the River Houses year. Our great star for the month of June is Spica, which we’ll be writing about next week. Print your own River Houses Star Calendar and follow along with us through the year as we learn about twelve high lights of the northern hemisphere night sky.

June is also the month of the summer solstice in the northern hemisphere — the astronomical beginning of summer — which falls this year on Friday the 21st. (In the southern hemisphere the 21st will be the winter solstice — the astronomical beginning of winter.) The summer solstice is the “longest day” of the year: the day with the longest period of daylight and the shortest period of darkness.

What celestial observations will you and your students be making in your homeschool this month? 😊

❡ Watchers of the skies: Teaching your students to recognize the constellations is one of the simplest and most enduring gifts you can give them. The planisphere on the front of your River Houses star atlas (riverhouses.org/books) will let you dial up the northern hemisphere sky for any night of the year, and the descriptions and maps of each constellation will point out the highlights. Find a dark-sky spot near you this month and spend some quality homeschool time beneath the starry vault. 🔭

❡ Star bright: This is one of our regular Homeschool Astronomy posts. Add your name to our River Houses mailing list (riverhouses.org/newsletter) and get great homeschool teaching ideas delivered right to your mailbox every week. 😊

For live links, click to: riverhouses.org/2019-may-sky 😊

On the first Saturday of every month we post educational skywatching notes for the homeschool month ahead. Here’s a monthly northern hemisphere review for May 2019, courtesy of the Hubble Space Telescope’s website:

And here’s another May review, courtesy of NASA’s Jet Propulsion Laboratory:

For serious homeschool skywatchers, the weekly updates from Sky & Telescope magazine provide a wealth of additional detail. Here’s the latest one:

• ➔ This Week’s Sky at a Glance, 3–11 May 2019

The best stargazing nights in May will be toward the beginning of the month — the moon is new (and the sky darkest) today, the 4th. As always, you can track the moon’s phases at the excellent timeanddate.com website.

May is the third month of Leo Term, the third of the four three-month terms that make up the River Houses year. Our great star for the month of May is Polaris, the North Star, which we’ll be writing about next week. Print your own River Houses star calendar and follow along with us through the year as we learn about twelve of high lights of the northern hemisphere night sky.

What celestial observations have you made in your homeschool lately? 😊

❡ Watchers of the skies: Teaching your students to recognize the constellations is one of the simplest and most enduring gifts you can give them. The planisphere on the front of your River Houses star atlas (riverhouses.org/books) will let you dial up the northern hemisphere sky for any night of the year, and the descriptions and maps of each constellation will point out the highlights. Find a dark-sky spot near you this month and spend some quality homeschool time beneath the starry vault. 🌠 🔭 🌌

❡ Star bright: This is one of our regular homeschool astronomy posts. Add your name to our River Houses mailing list and get more great homeschool teaching ideas delivered right to your mailbox every week. 😊

For live links, click to: riverhouses.org/2019-april-sky‎ 😊

On the first Friday of every month we post educational skywatching notes for the homeschool month ahead. Here’s a monthly northern hemisphere review for April, courtesy of the Hubble Space Telescope’s website:

And here’s another April review, courtesy of NASA’s Jet Propulsion Laboratory:

For serious homeschool skywatchers, the weekly updates from Sky & Telescope magazine provide a wealth of additional detail. Here’s the latest one:

• ➔ This Week’s Sky at a Glance, 5–13 April 2019

The best stargazing nights in April will be toward the beginning of the month — the moon will be new (and the sky darkest) on the 5th (today). As always, you can track the moon’s phases at the excellent timeanddate.com website.

April is the second month of Leo Term, the third of the four three-month terms that make up the River Houses year. Leo the heavenly lion is up in the east every evening at sunset now, and by ten o’clock he’s high overhead. Be sure to have your students find him and his great alpha star, Regulus — about which we’ll have more to say soon.

What celestial observations have you made in your homeschool lately? 😊

❡ Watchers of the skies: Teaching your students to recognize the constellations is one of the simplest and most enduring gifts you can give them. The planisphere on the front of your River Houses star atlas (riverhouses.org/books) will let you dial up the northern hemisphere sky for any night of the year, and the descriptions and maps of each constellation will point out the highlights. Find a dark-sky spot near you this month and spend some quality homeschool time beneath the starry vault. 🌠 🔭 🌌

For live links, click to: riverhouses.org/2019-ashokan-fireball 😊

One of the independent research activities we recommend to homeschoolers is reporting fireballs — unusually bright meteors — through the online system developed by the American Meteor Society. If you were out early yesterday morning in the northeastern United States, you might have seen a big one that has now been reported by more than 250 people in fourteen states.

Alas, I probably just missed seeing it by about fifteen minutes. 😖 Fireball reporting is a decidedly unpredictable activity, of course, but it’s worth reading about in advance so you’ll know what to look for and what record should one happen to cross your homeschool skies.

The many reports that AMS has received on this particular event indicate that the object traveled from southeast to northwest over the Catskill Mountains of New York. (Send your students to your family atlas to find them.) It was seen by observers as far north as Maine and as far south as West Virginia. AMS has also received one video of the event thus far:

I’ve reported a couple of fireballs to AMS myself over the years. Keep your eyes on the sky and the next big fireball report might come from you. 🌠

What celestial wonders have you observed in your homeschool this week? 😊