Post Archives: Watchers of the Skies

Then felt I like some watcher of the skies
When a new planet swims into his ken.

—Keats

Great homeschool teaching ideas and little lessons on stars, planets, constellations, comets, meteors, galaxies, space exploration, and other astronomy-related topics from the River Houses Homeschool Network. Add your name to our River Houses homeschool mailing list and get these posts delivered right to your mailbox every week! 😊

🌌 ASTRONOMY-PICTURE-OF-THE-DAY: Vega and the Milky Way

17 August 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-apod-vega

One of the best educational astronomy sites you and your homeschoolers can follow online is NASA’s Astronomy-Picture-of-the-Day site (apod.nasa.gov). For several years they’ve been posting a daily high-quality astronomy image with a paragraph or two of explanation that outlines what the image represents. It’s a great five-minute astronomy lesson that you can easily incorporate into your homeschool schedule.

You can also search back through the APOD archives to find pictures on topics that may interest you. Here in the River Houses our Great Star for the month of August is Vega, and the Perseid meteor shower just passed a few days ago, so what better image could we look up on APOD than this beautiful photo from August 2008 of the Milky Way with a Perseid streaking across it, and with Vega and its constellation Lyra, lying on its side, shining off to the right.

Perseid meteor trail with Vega and the Milky Way. (Image: Wally Pacholka via apod.nasa.gov.)

The APOD editors helpfully explain what we’re looking at:

“This bright and colorful meteor flashed through [the] early morning skies, part of the annual Perseid Meteor Shower. The lovely image is one of over 350 frames captured on August 12 [2008] from the Joshua Tree National Park, in California, USA. Dust from comet Swift–Tuttle is responsible for the Perseids, creating the northern hemisphere’s regular summer sky show. The comet dust is vaporized as it enters the atmosphere at upwards of 60 kilometers per second, producing visible trails that begin at altitudes of around 100 kilometers. Of course, the trails point back to a radiant point in the constellation Perseus, giving the meteor shower its name. Recorded after moonset, the starry background features the bright star Vega on the right. Extending below the western horizon is the faint band of the northern Milky Way.“ (apod.nasa.gov)

Why not add apod.nasa.gov to your list of homeschool science bookmarks and pay it a visit whenever the stargazing spirit strikes you. 🔭

What stellar spectacles are you studying in your homeschool this week? 😊

❡ Watchers of the skies: This is one of our regular Homeschool Astronomy posts. Add your name to our free weekly mailing list (riverhouses.org/newsletter) and get great homeschool teaching ideas delivered right to your mailbox all through the year. 🗞

🌟 STAR BRIGHT: Vega for August

10 August 2019 by Bob O'Hara

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

August is the last month of Hercules Term in the River Houses, and as our monthly star calendar will tell you, August’s Great Star is Vega, the brightest star in the constellation Lyra the Lyre. Its formal designation is α Lyrae — “alpha of Lyra.” Vega is one of my favorites and it’s almost directly overhead (near the zenith) every evening this month just after sunset, passing off to the west as the night goes on.

The constellation Lyra the Lyre and its alpha star, Vega. (Image: Wikimedia Commons.)

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

“Lyra is easily identified because of Vega, a brilliant white star of magnitude 0.0, the fourth brightest star in the sky and the second brightest visible from northern latitudes. Four smaller stars lie in a faint but conspicuous parallelogram just to the southeast of Vega. Although a small constellation, Lyra is rich in stars; sweep slowly with binoculars, particularly the area between β [beta] and γ [gamma] Lyrae. Do not fail to observe β [beta] Lyrae, an eclipsing binary whose light changes are visible to the naked eye, the magnitude varying from 3.4 to 4.3. ε [epsilon] Lyrae is the famous “double double”; persons with very keen eyesight can see the two components. They are easily split with binoculars. In a telescope, each of the components itself becomes a double.“ (Celestron Sky Maps, page 12)

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

Because of its prominence in the northern hemisphere night sky, Vega has played an important role in the development of modern astronomy. It was the first star other than the sun to be photographed (by daguerreotype in 1850), and the first star other than the sun to have its spectrum analyzed (in the 1870s). When the scale of stellar magnitudes was refined during the nineteenth century, Vega was chosen as the principal reference star with a defined magnitude of 0.0.

A true-color image of blue-white Vega, the alpha star of the constellation Lyra. (Image: Stephen Rahn via Wikimedia Commons.)

Modern calculations put Vega at a distance of about 25 light years — practically next door in astronomical terms. It’s estimated to be about two and a half times the diameter of the sun, but it is rotating so rapidly that it bulges out at the equator, making it more egg-shaped than spherical. It’s also quite a bit younger than the sun, with an estimated age of only 455 million years (compared to the sun’s age of more than 4.5 billion).

This month, 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. ✨

❡ Star bright: The brightness of a star as we see it in our night sky is its magnitude — or more properly speaking, its apparent magnitude. The scale of star magnitudes was developed centuries ago, long before modern measuring instruments were invented, so it can be a little bit confusing for beginners. Originally, the brightest stars in the sky were called “first magnitude” and the less-bright stars “second magnitude,” “third magnitude,” and so on, down to the dimmest stars visible to the naked eye, which were called “sixth magnitude.” In the nineteenth century the star Vega (our August star) was chosen as the standard brightness reference and its value on the magnitude scale was defined to be zero (0.0). Five steps in magnitude (from 0.0 to 5.0 or from 1.0 to 6.0) was defined to be a change in brightness of 100 times: a star 100 times dimmer than Vega (0.0) was defined to be a magnitude 5.0 star. Vega is not quite the brightest star is the sky, however, so the scale also had to be extended into negative numbers: Sirius, for example, is magnitude –1.5, about three times brighter than Vega (at 0.0). The planet Venus at its brightest is about magnitude –4.2; the full moon is about magnitude –12.9; the sun is magnitude –26.7. By contrast, the dimmest stars visible to the naked eye in a populated, light-polluted area are about magnitude 3.0; the dimmest stars visible under very dark conditions are about magnitude 6.5. The Hubble Space Telescope has imaged distant stars and galaxies below magnitude 30, the dimmest celestial objects humans have seen so far. 🔭

❡ 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 most notable 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 — and make each one of them a homeschool friend for life. 🌟

🌠 PERSEID METEORS for August 2019

9 August 2019 by Bob O'Hara

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

The annual Perseid meteor shower peaks each year around 12–13 August, so this weekend is the time to be on the lookout — make it an annual homeschool tradition! You can get some quick facts and local observing recommendations at the helpful timeanddate.com website:

➢ Perseid Meteor Shower – Observing Tips

The Perseids appear to radiate from the constellation Perseus, which rises in the east about 11:00 p.m. at this time of year, so that’s the general direction you’ll want to be looking. Your River Houses star atlas (riverhouses.org/books) will let you dial up a map of the constellations for this night (or any night) and will help you orient yourself to the sky overhead.

Meteor showers like the Perseids occur when the earth in its orbit around the sun passes through the trail of debris left behind by a comet making its orbit around the sun (that’s why they occur at the same time each year). You and your students can learn all about meteors and meteor showers on the website of the American Meteor Society — here are some of their resources:

The AMS also has a printable poster of basic meteor terminology — it’s just the thing for your homeschool bulletin board.

Meteor terminology, a free printable poster available from the American Meteor Society.

There is a truly remarkable interactive animation of the Perseid meteor shower and its parent comet available from the website meteorshowers.org. Until quite recently, interactive animations of this kind would have been available only on the most advanced computers, but now you can examine them in detail from the comfort of your little home academy. 😊

<span class="fb-only">For animation see: riverhouses.org/2019-perseids<span>

Note that this animation is fully interactive: by dragging and scrolling across the screen you can tilt the plane of the solar system to view it from above or below, and you can zoom in on the earth’s or the comet’s orbit. (The earth is the blue planet orbiting third from the sun.)

Pay a nighttime visit to a dark-sky location near your homeschool in the next few days, look toward Perseus, and see what shooting stars you can see. 🌠

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. 😊

🌠 WONDERFUL WORDS: “A Star in a Stoneboat”

8 August 2019 by Bob O'Hara

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

The annual Perseid meteor shower is expected to peak this coming weekend, but this year the meteors will be competing with a nearly full moon, alas. The Perseids may be wonderful or washed out, but our homeschool poem-of-the-week for this second week of August will still be a playfully brilliant verse drawn from the world’s small store of meteor poems: Robert Frost’s “A Star in a Stoneboat.”

Usually we dive right in with the text, but this week your students really do have to know first what a stoneboat is. It’s not a boat, and it’s not made of stone; it’s a piece of farm equipment like a sled or toboggan that’s used for dragging stones out of a field. Frost was a New England poet, and here in New England if you wanted to plant an acre of corn, you first had to drag a few tons of rocks out of the way.

“Stone boats were the pick-up trucks of yesterday.” (Image: Stoneboat Farm, Hillsboro, Oregon.)

And since wise old farmers never let anything go to waste, those few tons of rocks were generally piled up along the edge of the field where they served pretty well to keep the pigs out of the corn, too.

Stone wall beside Nathaniel Hawthorne’s “Old Manse” in Concord, Massachusetts. (Image: Robert Thorson via atlasobscura.com.)

With that background — that stoneboats were the pickup trucks of yesterday — we can proceed with the meteoric tale of “A Star in a Pickup Truck.”

A Star in a Stoneboat

Never tell me that not one star of all
That slip from heaven at night and softly fall
Has been picked up with stones to build a wall.

Some laborer found one faded and stone-cold,
And saving that its weight suggested gold
And tugged it from his first too certain hold,

He noticed nothing in it to remark.
He was not used to handling stars thrown dark
And lifeless from an interrupted arc.

He did not recognize in that smooth coal
The one thing palpable besides the soul
To penetrate the air in which we roll.

He did not see how like a flying thing
It brooded ant eggs, and had one large wing,
One not so large for flying in a ring,

And a long Bird of Paradise’s tail
(Though these when not in use to fly and trail
It drew back in its body like a snail);

Nor know that he might move it from the spot —
The harm was done: from having been star-shot
The very nature of the soil was hot

And burning to yield flowers instead of grain,
Flowers fanned and not put out by all the rain
Poured on them by his prayers prayed in vain.

He moved it roughly with an iron bar,
He loaded an old stoneboat with the star
And not, as you might think, a flying car,

Such as even poets would admit perforce
More practical than Pegasus the horse
If it could put a star back in its course.

He dragged it through the plowed ground at a pace
But faintly reminiscent of the race
Of jostling rock in interstellar space.

It went for building stone, and I, as though
Commanded in a dream, forever go
To right the wrong that this should have been so.

Yet ask where else it could have gone as well,
I do not know — I cannot stop to tell:
He might have left it lying where it fell.

From following walls I never lift my eye,
Except at night to places in the sky
Where showers of charted meteors let fly.

Some may know what they seek in school and church,
And why they seek it there; for what I search
I must go measuring stone walls, perch on perch;

Sure that though not a star of death and birth,
So not to be compared, perhaps, in worth
To such resorts of life as Mars and Earth —

Though not, I say, a star of death and sin,
It yet has poles, and only needs a spin
To show its worldly nature and begin

To chafe and shuffle in my calloused palm
And run off in strange tangents with my arm,
As fish do with the line in first alarm.

Such as it is, it promises the prize
Of the one world complete in any size
That I am like to compass, fool or wise.

This is a wonderfully clever poem — a long string of comparisons and contrasts — and you and your students can spend quite a bit of time trying to figure it out sentence by sentence. I won’t go through all the components here, but just look first at the very tight structure. “A Star in a Stoneboat” is made up not of couplets (rhymed pairs) but of triplets, where all three line-ends rhyme: all–fall–wall, cold–gold–hold, remark–dark–arc, all through the entire poem. That’s fairly uncommon in English, and it’s difficult to do. Next, count syllables: you’ll find that every line has exactly ten. The constraints Frost imposed on himself in adopting this compact form account for some of the complexities of the poem’s word-order, which admittedly can take a bit of effort to follow.

What the content of the poem generally does throughout is contrast the “life” of this imagined meteor once upon a time when it was flying through space, with its “life” after its arc was interrupted and it ignominiously landed in some farmer’s field, got pried out of the ground by a workman, and was dumped onto a stoneboat. Formerly it had raced past the planets; now it’s keeping pigs out of the corn. “Yet ask where else it could have gone as well, / I do not know.” See how many earthly–heavenly contrasts or comparisons your students can identify, all of them mediated by this imagined meteorite. And ask them if they’d like to be, like the narrator, a wanderer along the walls, mile on mile, searching for stones that had once been stars.

“From following walls I never lift my eye, / Except at night to places in the sky / Where showers of charted meteors fly.” (Image: Wikimedia Commons.)

What wonderful words have you found and what literary discoveries have you made in your homeschool this week? 😊

❡ Stars thrown dark: If a special line or turn of phrase happens to strike you in one of our weekly poems, just copy it onto your homeschool bulletin board for a few days and invite your students to speak it aloud — that’s all it takes to begin a new poetical friendship and learn a few lovely words that will stay with you for life. 🌠

❡ Explore more: The Poetry Foundation’s website includes biographical notes and examples of the work of many important poets (including Robert Frost) that are suitable for high school students and homeschool teachers. 🖋

❡ Here, said the year: This post is one of our regular homeschool poems-of-the-week. Print your own River Houses Poetry Calendar (riverhouses.org/calendars) and follow along with us as we visit forty-eight of our favorite friends. 📖

🔭 WATCHERS OF THE SKIES – August 2019

3 August 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-august-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 August 2019 from the Hubble Space Telescope’s website — the first star mentioned is Vega, our homeschool Great Star this month, which we’ll be writing more about next week:

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And here’s another August night-sky review, courtesy of NASA’s Jet Propulsion Laboratory in California. It particularly features the annual Perseid meteor shower that will peak on the 12 and 13th of this month in association with a nearly full moon, alas, that will wash out many of the fainter flashes:

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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, 2–10 August 2019

Overall, the best stargazing nights in August will be toward the beginning and end of the month: the moon will be full (and the dimmer stars less visible) on the 15th. As always, you can look up the moon’s phases in your River Houses almanac (riverhouses.org/books) and also at the excellent timeanddate.com website.

August is the last month of Hercules Term, the fourth of the four terms that make up the River Houses year. Our new school year will begin on the first of September. Download a print your own copies of our River Houses homeschool calendars (riverhouses.org/calendars) and follow along with us.

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. 🔭

🚀 🌎 APOLLO 11 RETURNED TO EARTH 50 Years Ago Today

24 July 2019 by Bob O'Hara

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

The first men to walk on an alien world returned safely to earth 50 years ago today. Getting to the moon and landing on it was a challenge, but if the Apollo 11 crew could not make it back home, then all would have been lost. Here’s a professionally done animation you can show your students this week to explain all the steps involved in getting from the surface of the moon back to earth:

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The most hazardous phase of the return flight is reentry into the earth’s atmosphere, when friction produces incredible temperatures on the bottom surface of the capsule. (The same effect causes most meteoroids — “shooting stars” — to burn up in the atmosphere.) During this reentry phase there is a also nerve-wracking radio blackout for a brief interval before contact is reestablished, the parachutes open, and the capsule safely strikes the water.

The Apollo 11 capsule *Columbia* safely floating in the Pacific with the astronauts awaiting transfer to the U.S.S. *Hornet*, 24 July 1969. (Image: NASA.)

The Apollo 11 crew and the Columbia capsule were fished out of the Pacific by the crew of another fine ship, the U.S.S. Hornet aircraft carrier. The Hornet is now a floating museum in San Francisco Bay that you and your homescholars can perhaps visit someday:

➔ U.S.S. Hornet Sea, Air, & Space Museum – Apollo 11 Splashdown 50th Anniversary Celebration

Here’s one more interesting historical anecdote you can share with your students about the Columbia capsule. That tiny room — think of it as a room — was an intense workshop and laboratory, with all three astronauts engaged in difficult operational and scientific activity throughout the mission. It turns out that during their daily work they scribbled quite a bit of stuff on the walls and instrument panels: navigational calculations, notes about the equipment, and more. After their safe splashdown and recovery, Mike Collins got the urge to go back into the capsule and write a note of thanks, which he did, and which can be seen there to this day.

Command Module Pilot Michael Collins’ note of thanks written on the inside of the *Columbia* capsule shortly after its safe return: “Spacecraft 107 – alias Apollo 11 / alias ‘Columbia’ / The Best Ship to Come Down the Line / God Bless Her / Michael Collins / CMP.” (Image: NASA.)

The Columbia capsule is now housed at the National Air and Space Museum in Washington, but the museum’s website says it is not currently on display — so if you want to see it in person you may have to wait for a future opportunity.

What other grand historical anniversaries are you studying in your homeschool this month? 😊

❡ Come, here’s the map: If you turn to plate 109 in your recommended homeschool atlas (riverhouses.org/books) you’ll be able to locate the section of the Pacific Ocean about 800 miles southwest of Hawaii — notably empty, of course — where Apollo 11 made its final splashdown. 🌎

❡ Stay in the loop: This is one of our regular Homeschool Holidays & Anniversaries posts. Add your name to our free weekly mailing list (riverhouses.org/newsletter) and get great homeschool teaching ideas delivered right to your mailbox all through the year. 🗞

🌕 A LUNAR SAMPLE COLLECTION for Your Local Library?

23 July 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-lunar-samples

Tuesday is our regular Books & Libraries Day in the River Houses, and since we’ve been celebrating the 50th anniversary of the first moon landing for the last few days, here’s a rare educational opportunity you might be able to work on with your local library: borrowing some actual moon rock samples for students to examine.

This is not a homeschool program specifically — in fact, it’s a rather tightly controlled NASA education program that is open only to paid employees of educational institutions who attend a special training program at a NASA site. But professional librarians do qualify, and if this catches your imagination you might consider working with your local library to make it into a special community education activity.

Students examining rock and soil samples from the moon. (Image: NASA.)

The program and the application process are quite elaborate — they’re outlined on NASA’s educational materials website:

➔ NASA Lunar & Meteorite Sample Disk Program (K–12)

If homeschoolers were to collaborate with their local library they might not only be able to bring this distinctive educational opportunity to their community, but they could also generate favorable publicity for all concerned. (“Moon Rocks Coming to Town,” the local paper will shout.) 😊

Lunar and meteorite sample disks. (Image: NASA.)

Here’s a NASA video that describes the sources of the samples, the sample program, and the procedures involved in requesting and storing the borrowed materials:

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This isn’t a simple weekend project — you’d have to work on it in association with a local library over a period of several months. But it’s an exceptional opportunity to bring genuine samples from an alien world right into your students’ hands. That makes it worth exploring. 🚀

What treasures have you discovered at your library lately? 😊

❡ Dukedoms large enough: Have you found all the local libraries in your area? There may be more than you realize, and there’s no better homeschool field trip than a field trip to a new library! The WorldCat Library Finder will help you find all the library collections near you — public and private, large and small — and the WorldCat catalog itself will help you locate the closest copy of almost any book in the world. 😊

❡ When in doubt, go to the library: This is one of our regular Homeschool Books & Libraries posts. Add your name to our weekly mailing list (riverhouses.org/newsletter) and get great homeschool teaching ideas delivered right to your mailbox all through the year. 📚

🚀 🌕 APOLLO 11 RESOURCES for Your Homeschool

19 July 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-apollo-11

As the whole world knows, this week is the 50th anniversary of the Apollo 11 moon landing. Here’s a roundup of some great Apollo resources you can use over the next few days with your homeschool students.

If you watch just one special thing this week as a family event, I highly recommend this new documentary called simply “Apollo 11,” produced almost entirely from rarely-seen footage kept by the National Archives in Washington. It’s a full-length film that is showing in selected theaters, and it’s also available online from services like Amazon Prime:

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NASA of course has a wide selection of special materials online this week (even a printable crossword puzzle for your students):

➔ Apollo at 50 (from NASA)

The website Space.com also has an excellent review of the whole series of Apollo missions with many video clips and links to additional information:

➔ Apollo 11 at 50: A Complete Guide to the Historic Moon Landing (from Space.com)

And for some tangible fun, be sure to stop by your local post office this week to pick up some of the dramatic new Apollo 11 anniversary stamps:

➔ Apollo 11 First Moon Landing Stamps (from usps.com)

And I’d say your students should recognize the source of the astronaut image on those stamps as part of their cultural, historical, and scientific education. It’s one of the most famous images in history: Neil Armstrong’s photograph of Buzz Aldrin standing on the lunar surface, taken with the 70 mm Hasselblad cameras that were used on all the Apollo missions. (No digital photography back then, you know — the rolls of film had to come back to earth and get developed in a tank before anyone would know what the pictures looked like.)

Astronaut Buzz Aldrin on the lunar surface, 20 July 1969, with his crewmate Neil Armstrong and the lunar module reflected in his visor. (Image: National Archives.)

How will you be celebrating and studying this historic, scientific, astronomic anniversary in your homeschool this week? 😊

❡ The Eagle has landed: If you turn to plate 123 in your recommended homeschool atlas (riverhouses.org/books) you’ll be able to locate the Sea of Tranquility where the Apollo 11 lander touched down for the first time. (Did you know your atlas has maps of the moon? It does!) 🌕

🌟 STAR BRIGHT: Arcturus for July

13 July 2019 by Bob O'Hara

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

July is the middle month of Hercules Term in the River Houses, and as our monthly star calendar will tell you, July’s Great Star is Arcturus, the brightest star in the constellation Boötes the Herdsman. Its formal designation is α Boötis — “alpha of Boötes.” Boötes and Arcturus are already high overhead in the early evening this month, passing off to the west as the night goes on. With Regulus (our April star) and Spica (our June star), Arcturus forms “the Spring Triangle” (even though we’re now into summer).

The constellation Boötes the Herdsman and its alpha star, Arcturus. Note the handle of the Big Dipper in the upper right; follow back along the handle’s “arc to Arcturus” to locate this great northern hemisphere star. (Image: Wikimedia Commons.)

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

“Boötes is an easily recognized constellation resembling a huge kite. Arcturus, its brightest star, has a magnitude of –0.1 and is the 4th brightest star visible from Northern latitudes. Arcturus can be located by following backwards the curve of the Big Dipper handle; the curved line connecting these stars extended about 30º will lead your eye to Arcturus. It is a giant star about 80 times as bright as the sun and is 37 light years away.“ (Celestron Sky Maps, page 8)

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

Arcturus is an ancient orange-yellow giant about seven billion years old. It has roughly the same mass as our sun, but it has expanded to enormous size as its supply of hydrogen has become depleted. It’s also relatively close to us — current estimates of its distance put it at about 37 light years. It’s generally thought to be a single star, without any companions.

Optical image of Arcturus. To the naked eye it usually appears slightly yellowish — not bright white like Sirius, Spica, or Vega. The small bluish star at seven o’clock in this image is a random background star, not physically associated with Arcturus. (Image: NASA via Wikimedia Commons.)

The name Arcturus comes from the Greek and means “watcher of the bear” or “guardian of the bear” — a reference to its association with the constellation Ursa Major (the Great Bear, including the Big Dipper), which Boötes and Arcturus follow around the pole. Arcturus and the other stars of Boötes were well known to the Greeks, and as with any ancient celestial configuration they are surrounded by many different and sometimes contradictory mythological accounts of their origins.

This month, 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? 😊

❡ Star bright: The brightness of a star as we see it in our night sky is its magnitude — or more properly speaking, its apparent magnitude. The scale of star magnitudes was developed centuries ago, long before modern measuring instruments were invented, so it can be a little bit confusing for beginners. Originally, the brightest stars were called “first magnitude” and the less-bright stars “second magnitude,” “third magnitude,” and so on, down to the dimmest stars visible to the naked eye, which were called “sixth magnitude.” In the nineteenth century the star Vega (our August star) was chosen as the standard brightness reference and its value on the magnitude scale was defined to be zero (0.0). Five steps in magnitude (from 0.0 to 5.0 or 1.0 to 6.0) was defined to be a change in brightness of 100 times: a star 100 times dimmer than Vega (0.0) was defined to be a magnitude 5.0 star. Vega is not quite the brightest star is the sky, however, so the scale also had to be extended into negative numbers: Sirius, for example, is magnitude –1.5, about three times brighter than Vega (at 0.0). The planet Venus at its brightest is about magnitude –4.2; the full moon is about magnitude –12.9; the sun is magnitude –26.7. By contrast, the dimmest stars visible to the naked eye in a populated, light-polluted area are about magnitude 3.0; the dimmest stars visible under very dark conditions are about magnitude 6.5. The Hubble Space Telescope has imaged distant stars and galaxies below magnitude 30 — these are the dimmest objects seen so far.

🌝 KNOW YOUR MOONS! 🌑🌒🌓🌔🌕🌖🌗🌘🌑

11 July 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-moon-phases

There will be a lovely gibbous moon high up in the southern sky this evening. Can your homeschool students recognize the phases of the moon? Why not teach them the lunar cycle during this momentous month when we are remembering the 50th anniversary of the first moon landing.

Did you know there’s an emoji symbol for each phase of the moon? It’s true! Whenever we’re posting about the moon here at the River Houses we try to use the correct emoji, and you can do the same, illustrating the moon’s phases for your students, quizzing them with emojis, and inviting them to recite the northern-hemisphere formula, “fills in from the right, drains out to the left”:

🌑 NEW
🌒 WAXING CRESCENT
🌓 FIRST QUARTER
🌔 WAXING GIBBOUS ← tonight
🌕 FULL (second quarter)
🌖 WANING GIBBOUS
🌗 THIRD QUARTER
🌘 WANING CRESCENT
🌑 NEW (again)

A complete cycle, from new to new, is one (lunar) month — 29 days — and the word month and moon are in fact cognate words, having the same historical origin. (Compare the expression, “many moons ago,” meaning, “many months ago.”)

The time from one quarter to the next — from new to first quarter, from first quarter to full (second quarter), from full to third quarter, or from third quarter to new again — is about seven days, and that’s the basis for the week, which is a quarter of a month: four quarters in one “moon,” four weeks in one month. (This also explains why lunar terminology is sometimes confusing to beginners: the first and third “quarter” moons are half full, because “quarter” doesn’t refer to appearance but rather to a given point within the monthly lunar cycle.)

Commemorative 2019 stamp marking the 50th anniversary of the Apollo 11 moon landing. The landing site in the Sea of Tranquility, which you can locate on a clear night with binoculars, is indicated by a yellow dot. (Image: U.S. Postal Service.)

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

❡ Crescent and gibbous and waxing and waning: The word crescent is common in English in many contexts, but the word gibbous — convex, bulging, humped, hunchbacked — is much less common and is rarely used today to describe anything other than the moon, which is a shame because it’s a wonderful word. Similarly, waxing (growing, increasing) and waning (shrinking, decreasing) are used most often now as paired terms in the context of the moon, but they do still survive in a few other contexts (to wax poetic; his interest waned). 🌔 🌘

❡ Watchers of the skies: 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. 😊

🎥 MOVIES & LIBRARIES: Apollo 11 at the National Archives

9 July 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-apollo-11-film

The 50th anniversary of the Apollo 11 moon landing is this month (Saturday the 20th), and one of the best commemorations that has so far appeared is a full-length documentary called simply Apollo 11. It’s showing in some theaters and can be purchased online — I’ve seen it, and I recommend it highly to all homeschool families.

This documentary is based almost entirely on never-before-seen footage of the Apollo 11 mission that is stored in the U.S. National Archives. For this Homeschool Books & Libraries post, here’s a three-minute background video from the National Archives that shows some of the materials that went into the creation of the full-length film, and how the Archives staff cares for and processes those materials:

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Every homeschool student should know the story of the Apollo 11 mission (and of manned spaceflight in general), and this 50th anniversary documentary is an excellent way to teach about it.

“Crafted from previously unseen 70mm film footage and more than 11,000 hours of uncatalogued audio recordings, [this] new documentary transports moviegoers to the heart of NASA’s most celebrated mission — Apollo 11, the one that first put men on the Moon and forever made Neil Armstrong and Buzz Aldrin into American icons.

“Newly digitized footage discovered at the National Archives and Records Administration plays a major role in the new documentary that allows viewers to experience the perspectives of the astronauts, the Mission Control team, and the millions of spectators on the ground. The film showcases the days and hours in 1969 when American astronauts took “a giant leap for mankind” into the future.“ (National Archives)

Here’s the commercial trailer for the full-length documentary itself:

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Do you have a moon party planned for the 20th? 🌕

What educational discoveries have you made at your library lately? 😊

🔭 WATCHERS OF THE SKIES – July 2019

6 July 2019 by Bob O'Hara

For live links, click to: riverhouses.org/2019-july-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 July from the Hubble Space Telescope’s website:

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This July 20th is a very important anniversary: the 50th anniversary of the first moon landing in 1969. Here’s another July night-sky review, courtesy of NASA’s Jet Propulsion Laboratory in California, which features some special facts about the moon that you can share with your students during this anniversary month:

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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, 3–13 July 2019

The best stargazing nights in July will be toward the beginning and the end of the month: the moon was new (and the sky darkest) on the 2nd, and it will be new again on the 31st. As always, you can look up the moon’s phases in your River Houses almanac (riverhouses.org/books) and also at the excellent timeanddate.com website.

July is the middle month of Hercules Term, the last of the four three-month terms that make up the River Houses year. Our Great Star for the month of July is Arcturus, which we’ll be writing about next week. Print your own River Houses Star Calendar (riverhouses.org/calendars) and follow along with us through the year as we learn about twelve high lights of the northern hemisphere night sky.

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. 🔭