This is the Classical Astronomy Update, an email newsletter especially
for Christian homeschool
families (though everyone is welcome!) Please feel free to share this with any interested friends.
The high hills are a refuge for the wild goats; and the rocks for the
conies. He appointed the moon for seasons: the sun knoweth his
going down. Thou makest darkness, and it is night: wherein all
the beasts of the forest do creep forth. -- Psalm 104:18-20
IN THIS UPDATE
Connecting the Stars of a Constellation
Opposition of Saturn and Jupiter
Hello Friends,
Welp, I still haven't gotten around to doing the promised webinars. I really do hope to block out time for that sometime soon. So if you wrote to indicate interest, please bear with me!
I got an email a while back from Misty who asked if I could debunk the tenets of "flat earth." This flat earth topic is a total absurdity, but we're living in such absurd times. I really hope to take some time to write that up sometime soon. There's a lot that could be said.
Lately, I usually get motivated and make the time for writing a newsletter when there is a relevant sky event. I've gotten out of the habit over the years of writing regularly scheduled newsletters. Once upon a time, this newsletter was driven almost entirely by questions. Maybe about 15 years ago, I used to get these nice, friendly emails from readers, addressed to me personally, where someone would write a
chatty paragraph or two to ask a thoughtful question about some aspect of astronomy. But over time, the questions became fewer and further between. Such communications as I did receive from readers became short, terse, one-line messages that usually did not address me by name. I noticed that these brief, infrequent messages included a footer that said "sent from my iPhone."
I've never gotten a smartphone in all these years, and I still have no regrets. I stick with my flip phone, which I use for talking, the original purpose of a phone, as invented by Alexander Graham Bell. New technologies are always an incursion into human life, and while they might bring blessings, they also bring unintended negative consequences. I used to formerly enjoy a friendly reparte with the newsletter
readers. But the advent of the smartphone has contributed to my feeling disconnected from the readers of this newsletter.
Point being, I would still like to hear from you! If you ever have any astronomy questions, feel free to drop me an email. Yes, I understand that email is passe' in the era of texting, but this is an email newsletter and even if the world changes, I can't change what I do after so many years.
In other news, I recently had a handful of new orders for Signs & Seasons that came within the same 24 hour period. This was unexpected and might have been because someone posted a positive review online. If that was you, thank you very much! If not, I
encourage you to do so! Thanks in advance!
For more information about topics from Classical Astronomy
discussed in this newsletter, please check out
a homeschool astronomy curriculum
(but popular with adult readers too!)
Visit our archive of previous editions of the Classical Astronomy Update newsletters, going back to 2007.
*****
Connecting the Stars of a Constellation
One thing I’ve noticed is that every app or book has a different way of of connecting the stars of a constellation. Is there an official sky map, or are they left to private imagination?
Here's an expanded version of my answer.....
There are no official, standard "connect the dot" patterns for constellations. The International Astronomical Union (IAU) gives names to the planets and other celestial objects, in addition to making decisions like whether or not miniscule trans-neptunian objects such as Pluto should remain designated as planets. But the IAU has never established any official rules on how to draw the patterns of the
constellations.
Very often, one will see the constellations depicted as convoluted "connect the dot" patterns. I think the rationale with this approach is to present a pattern that involves as many stars as possible associated with a given constellation.
The problem I see is that such patterns connect stars of varying brightness. But not all stars are equally visible, especially from light polluted urban and suburban locations. So I believe this approach is counter-intuitive, since the human eye naturally connects bright stars to other bright stars and does not naturally perceive a connection between a bright star and a faint star. Such intricate constellation
patterns can be confusing and frustrating, especially to rookie skywatchers who are still learning the constellations.
One example of convoluted star patterns is found in "The Stars: A New Way to See Them" by H.A. Rey, the creator of the beloved Curious George series. The first edition of this book was published in 1952, when the skies over the USA were generally a lot darker than today. In those days, faint stars would have been more readily visible to the casual skywatcher. Here's how Rey envisioned the constellation
Gemini, the Twins:
This constellation pattern as drawn by Rey surely does resemble a couple of twins holding hands, and could be viewed as the Dioscuri of ancient myth, the twin brothers Castor and Pollux who sailed the ship Argo with the Greek hero Jason. I have actually been able to pick out this pattern from a sufficiently dark site. But Rey was the author of cute children's stories. I believe Rey's constellations were
intended to be cute star patterns for children, probably for kids and adults of the 1950s who already knew the constellations. But I do not find them to be a practical approach for rookies struggling to learn the constellations under the light polluted skies of the 21st century.
So while our family also loves Curious George and his creator, I think H.A. Rey's patterns are unnecessarily hard to discern, especially for novice skywatchers, and ultimately do more harm than good in learning to identify constellations. Nonetheless, even the authoritative astronomy magazine Sky & Telescope presents this and others of Rey's constellation patterns.
In our Signs & Seasons curriculum and this newsletter, I present the patterns as they appear to me the sky. I do most of my skywatching from my light polluted neighborhood, with occasional forays to the dark skies of rural areas. My
approach focuses on connecting the brighter stars into simple geometrical shapes, mostly involving stars of comparable brightnesses.
I did not invent this pattern for drawing Gemini, and you might find a comparably simple pattern in other publications. And on a given night, depending on light and atmosphere, not all of the stars in even this simple pattern will be visible. Sometimes I can only see the bright "twin" stars, Castor and Pollux, and maybe the "feet" of the twins. But if you can learn this simple pattern to start, you can
always go back and learn the more convoluted patterns like H.A. Rey's.
Unfortunately, it's becoming harder to spot even the brighter stars. With the recent advent of LED street lighting, night has turned to day and the roads are drenched with glaring bright white light. Even just this summer, I've found it harder to pick out the stars than in summers past. What used to be a murky orange glow on the horizon from the old high density sodium streetlighting is now a dazzling
white glow from LEDs. Many constellations close to the treeline are obliterated. The children of today may only hear stories about constellations from their grandparents.
So anyway, to answer Jonathan's original question, everyone is free to draw the constellations however they like!
Opposition of Saturn and Jupiter
Long time readers of the Classical Astronomy Update know that I like to mention the oppositions of the superior planets. If you don't know what "oppositions" are, or even which planets are "superior," these topics are explained in detail in our Signs &
Seasons astronomy curriculum.
Long story short, "opposition" is when one of the superior planets, those planets beyond the orbit of the Earth, appear at the "opposite" point in the sky from the Sun, at a position 180 degrees away from the Sun's position. At opposition, the planet rises when the Sun sets, and visa versa. After opposition, the planet remains visible after sunset for the remainder of its apparition, until it vanishes into the
sunset ahead of its superior conjunction.
Saturn was at opposition on August 2 and Jupiter is at opposition today, August 20. So we'll be able to see Jupiter rising at sunset, while Saturn will already be above the horizon as the Sun goes down.
In the current season, Saturn is passing through the constellation Capricornus, while Jupiter is passing through Aquarius. These star patterns are not very conspicuous so you may need to look for them from a rural site, far from the city lights.
It's hard to miss Jupiter since it's by far the brightest "star" in the sky. Jupiter is actually the fourth brightest object visible in the sky, after the Sun, the Moon and Venus, currently seen in the western sky as the Evening Star after sunset. And Saturn is the less-bright "star" somewhat to the west (right) of Jupiter in the sky. If you happened to notice Jupiter and Saturn when they had
their historic close conjunction last December, you might be amazed at how far apart these planets are now, only 8 months later.
If you still can't spot these planets, as a special treat, the Moon will be passing close by this weekend. The Moon will pass Saturn on the evening of Friday, August 20, 2021. The Full Moon will pass Jupiter the next evening, Saturday, August 21, 2021. So if you have clear skies in your area, please take a couple minutes to observe these pretty celestial alignments.
Til next time, God bless and clear skies,
- jay
The Ryan Family
Cleveland, Ohio, USA
When I consider thy heavens, the work of thy fingers, the moon and
the stars, which thou hast ordained, what is man that thou art
mindful of him? and the son of man, that thou visitest him?
- Psalm 8:3-4, a Psalm of David
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