Nov 01

What’s Up in the Sky

What’s Up in the Sky – November, 2017

Halloween and Astronomy?

Happy Halloween! This being the first time this column has been published on Halloween, I thought it might be fun to see if there was any connection between the holiday and astronomy. Turns out there is. And it stems from the customs and beliefs of early cultures.

Many Halloween traditions can trace their origins to the ancient Celtic festival of the harvest called Samhain (pronounced sah-win). But the date itself is also significant in an astronomical sense because it is a “cross-quarter date”.

We mark the beginnings of the seasons with what we call equinoxes and solstices, so the autumnal equinox marks the first day of autumn in September, and the winter solstice the first day of winter in December. But the dates roughly half-way between these seasonal boundaries, the cross-quarter dates, were also important to early cultures. (We still celebrate two other cross-quarter dates, Ground Hog day on February 2nd, and May Day on May 1st.)

To the early Celts, however, these dates marked the middle of the seasons, not the beginning, and so winter, the “dark season” actually began on the cross-quarter date approximately half-way between the fall equinox and winter solstice, October 31. This makes sense to me since November is much more winter-like than March and we often think of summer ending on Labor Day.

That’s where Samhain comes in. Roughly translated it means “summer’s end” and was the start of the dark season when everything died and the days grew cold. It was also the Celtic new-year’s eve and great bonfires were lit to keep evil spirits away. It was a time of both celebration and fear, as the light, living summer gave way to the dark, dead winter.

It was also a time of year when the well known star cluster, the Pleiades, reached its highest point in the sky around midnight. To the Celts, the Pleiades opened a path to the other world and when they reached their highest point in the sky, the barriers between the worlds broke down, and the souls of the dead could cross over into the world of the living.

The Full Moon is often associated with Halloween, usually depicted with the silhouette of a black cat or flying witch on her broomstick. Unfortunately, the Full Moon does not always fall on October 31, but it is a common image. This year, though, trick-or-treaters will be able to see an “almost-Full” Moon low in the southeast after dinner.

So I hope your day is somewhat enriched by the knowledge that your celebration has its origins up in the sky.

This month in history:
Nov. 3: The dog Laika is first living creature to orbit Earth, aboard Sputnik 2 – 1957
Nov. 9: Carl Sagan born. – 1934
Nov. 16: Interstellar message broadcast from Arecibo radio telescope – 1974
Nov. 20: Edwin Hubble born – 1889
Nov. 27: First photograph of a meteor shower – 1885
Nov. 30: Ten-pound meteorite strikes and bruises Alabama woman, Elizabeth Hodges-1954

Oct 21

What’s Up in the Sky

What’s Up in the Sky – October, 2017

An Historic Mission Comes to an End

On September 15, the Cassini spacecraft became part of Saturn when it melted into its atmosphere upon its final descent from orbit. NASA sent out a tweet that said, “Earth received Cassini’s final signal at 7:55 a.m., ET. Cassini is now part of the planet it studied.” The “Grand Finale” orbit that sent it plunging into oblivion was chosen as “moon protection”. Saturn has several moons on which conditions may be favorable for some life, and we didn’t want to contaminate it with any of our microbes.

Many readers know that the Cassini mission uncovered a number of mysteries through its extensive study of the planet’s rings, moons, atmosphere, magnetic field, and more. More than half a dozen previously unknown moons of Saturn were discovered by Cassini. It studied the planet’s seasons and spin. It also delivered a photo of Earth from Saturn that builds on the legacy of Carl Sagan’s pale blue dot.

The loss of Cassini marks the end of an era of “great missions” that used large, expensive, complex spacecraft such as Voyager and Galileo to accomplish their goals. Of course, these programs were tremendously successful and continued far past their designed time frames (Voyagers 1 and 2 are still sending back data!)

Cassini was launched in 1997 and reached Saturn in July, 2004, after flybys of Venus and Jupiter. It orbited the planet for the next 13 years, collecting data, taking magnificent photos and studying mysteries such as oceans of frozen methane on Titan, and salt water geysers on Enceladus, two of the planet’s moons.

Some of the scientists working on this project have been together since the planning and design stage, almost thirty years. For many, Cassini represents an entire career’s worth of work. The scientists became like family, watching each other’s kids grow up. They even formed a singing group.

For many of the 1000 people gathered at JPL (Jet Propulsion Lab) for the spacecraft’s final moments, the end of the mission was a bittersweet experience filled with mixed emotions. When asked about the moment contact with Cassini is lost, one scientist at mission control said, “Do we cheer or go into silence?”

But when you work on a project for 20 or 30 years with the same people, sharing important discoveries and contributing to an historic mission, it makes a lasting impression. One researcher described making discoveries with her colleagues as, “. . . a beautiful feeling; nothing like it in the world.”

Many of these project scientists will continue their work on other programs and some will retire. But the data collected during the entire mission will keep planetary scientists busy for a long time. The Cassini spacecraft has given us a great appreciation for the splendor of what’s up in the sky.

Aug 01

What’s Up in the Sky

What’s Up in the Sky – August, 2017

THIS IS IT!

In June I wrote about the wonders of witnessing a total solar eclipse like the one coming up on Monday, August 21, and encouraged readers to do some web searches for “information on locations and methods of safe viewing.”  Now, for those traveling to a viewing site along the path of totality, I will describe the eclipse’s “special events”, times during the event that you don’t want to miss.

I first must remind readers that at NO TIME should you ever look at the partially eclipsed Sun.  SOLAR ECLIPSE GLASSES should always be worn when observing the partial phases before and after totality.  Observing with a special solar telescope or one fitted with a proper solar filter is best done with an experienced observer who is familiar with the equipment.  Also be reminded that you have to be located along the path of totality, about an eight or nine hour drive south.

Now, about those “special” sights of interest.  The beginning of the eclipse occurs when the Moon first begins to cover the Sun.  For the next hour and a half the Moon moves slowly in front of the Sun, partially covering its disk.  View this phase best by projecting the image, do not look directly at the partially eclipsed Sun.

Since the timing of the events depends on your location, you will have to use outside resources such as solareclipsetimer.com to accurately predict them.  As the partial phase comes to an end, be aware of your total environment, the wind, the birds and insects, and the color of the sky both above and near the horizon.  As totality nears, be sure to watch through your solar eclipse glasses as the last sliver of the Sun disappears.  Immediately before this happens watch for “Bailey’s Beads” where the Sun still shines through the valleys on the Moon’s limb.  These gradually (in a few seconds) morph into a single, last bead that brightens dramatically and, when combined with the Sun’s corona (outer, bright atmosphere) forms the “diamond ring” effect.

Now totality begins.  In our area, it will last slightly less than three minutes.  It is not necessary to wear eye protection during totality, in fact you won’t see anything if you do.  The diamond will be gone but the beautiful ring remains.  You are standing in the shadow of the Moon and as it moves across the landscape you may be able to see its effects, depending on your view.  Some have witnessed “shadow bands” on the ground or the shadow itself moving over the distant horizon.

Check the time again and be ready to go back to eye protection for the end of totality when the Sun’s disk again is visible.  There may be a second diamond ring but afterwards the thin disk of the Sun will continue to grow.  During this last phase you will probably want to let it all sink in and form lasting memories.  In some circles it is customary to give a champagne toast to the most beautiful thing you will ever see up in the sky. (For a wonderful description of the eclipse, see: http://www.eclipse2017.org/2017/what_you_see.htm)

This month in history:

August 1:  Production of Saturn V rocket ends – 1968
August 3:  First in-flight space shuttle repair – 2005
August 6:  Curiosity rover lands on Mars – 2012
August 12: Echo 1 satellite launched – 1960
August 18: Helium discovered in the Sun – 1868
August 25: Voyager 2 flies past Neptune – 1989
August 28: Galileo spacecraft flies past asteroid Ida – 1993

Jul 06

What’s Up in the Sky

What’s Up in the Sky – July, 2017

Observe Three Planets This Month

July can be a great month for sky watching in spite of certain drawbacks.  First and foremost is the fact that the Sun sets after 9:00 p.m. all month, which means it doesn’t get dark enough for viewing until after ten.   Other hinderances include insects and humidity, but quite often the month provides at least a few favorable nights.

One way to get around the lack of darkness is to do lunar observing.  A first quarter Moon is visible well before sunset and can be viewed for several hours afterwards.  July begins with the Moon at this phase so there will be viewing opportunities for the first week of the month.  Just google “observing the Moon” for tips on when, where, and how to view the various mountains, valleys and craters.

Another opportunity occurs during the last week of July following the New Moon on the 23rd.  In fact, on Monday, July 24, the very thin crescent Moon is joined by the planet Mercury which is just below the star Regulus.  This will be a challenging but rewarding observation.  You will need binoculars or a small telescope and a clear, unobstructed view of the western horizon (Lake Michigan is a perfect spot).  Sunset that night is at 9:13 p.m. so begin your search about twenty to thirty minutes later.  Look slightly north of due west for the thin crescent of the Moon, then scan left (south) to spot Mercury and Regulus.  They will be the brightest objects in the area so if you see anything, that would be them.

You may want to follow this up with another try the following night when the Moon will be more toward the south and to the left of the other two objects.  You will also notice that Mercury will have gone from the lower right to the lower left of Regulus.  They will be separated by about the width of two fingers held at arm’s length.

Two other planets are well placed for observing in July: Jupiter and Saturn.  When darkness falls, look in the southwest for Jupiter and southeast for Saturn.  They should be easy to spot as they will be two of the brightest objects in that part of the sky.   Also, Jupiter will be just below the First Quarter Moon on June 30 and very close to the Crescent Moon on July 28. Saturn will be right below the Gibbous Moon on July 6.

The best viewing, however, will be the following week when the Moon is out of the way and the sky is dark.  A good telescope will give excellent views of Saturn’s rings and Jupiter’s moons.  A desktop planetarium such as Stellarium (http://www.stellarium.org/) can be used to predict dates and times of events such as transits and occultations of Jupiter’s moons.  Those are times when one or more of the moons either passes in front of the planet or disappears behind it.  Both are very interesting events you can observe up in the sky.

This month in history:
July 3:  Harrison Schmitt born – 1935
July 4:  Mars Pathfinder lands on Mars – 1997
July 6:  Newton’s book, Principia, is published – 1687
July 9:  Voyager 2 flies past Jupiter – 1979
July 20: First humans walk on Moon (Apollo 11) – 1969
July 24: First rocket launched from Cape Canaveral – 1950

Jun 01

What’s Up in the Sky

What’s Up in the Sky – June, 2017

The Great American Solar Eclipse

The monthly meeting of the Shoreline Amateur Astronomical Association on January 16, 1992 promised to be a fairly interesting event. Our guest was the accomplished Muskegon astrophotographer, Bill DeVette, who would be giving a talk titled, “Blackout in Baja”, during which he would share his experience observing and photographing the total solar eclipse of July 11, 1991, as viewed from Cabo San Lucas in Baja California, Mexico. As expected, Bill’s photos were stunning and his description of the eclipse was interesting, but what really blew most of us away was his cassette recording (remember, this was 1992) of the sounds of the people observing the eclipse.

For the first minute or so of the recording people were more or less milling around with casual conversations about the darkening sky, the equipment being used, and images being projected. All of a sudden the conversations stopped and cheering and shouting began. I remember thinking, what the heck is that all about? So I asked Bill that very question and he explained that this was a normal reaction for people witnessing a total solar eclipse – awe inspired exclamations of wonder and joy!

Fast forward to February 26, 1998. With the support of Fennville Public Schools I, as a teacher of astronomy, was able to travel with my wife, Lyne, to Aruba for another total eclipse of the Sun. It was there that I fully understood what I had heard on Bill’s tape recording. I was fairly involved with photographing the event for use in my classroom, but I did pause long enough to take in the splendor of one of nature’s most amazing spectacles. Lyne described it as “a mystical experience” and I can verify that it was a sight I will always remember. That is why I am greatly looking forward to the “Great American Eclipse” of August 21, 2017.

A total solar eclipse occurs when the Moon passes directly between the Earth and the Sun, casting its shadow on Earth’s surface. Just like the shadow of a beach ball on the sand, the Moon’s shadow is small compared to the entire Earth and as it moves over the terrain at about roughly 1000 miles per hour although this varies widely for different eclipses. In order to witness the total eclipse you have to be in the path of this shadow, called the path of totality. On August 21 this path stretches from Oregon to South Carolina, and is closest to us in parts of southern Illinois, Kentucky and Tennessee.

Just Google “eclipse 2017” and you will find an abundance of information on locations and methods of safe viewing. I just want to emphasize a couple of important points. During the partial phase of the eclipse, that is, before the Sun is completely covered, NEVER look directly at the Sun, no matter how small a crescent it is. West Michigan is not in the path of totality so NEVER look directly at it from here. During totality, ALWAYS look directly at the eclipsed Sun, even with binoculars it is safe. Just be sure to STOP LOOKING when totality ends. The best way to observe the partial phases is to project the Sun’s image onto a sheet of white paper with binoculars or a pinhole camera.

Again, all this information can easily be found online. My goal for writing this article is to encourage readers to take the time to travel a few hours to a location where totality can be observed. I guarantee you will not be disappointed by this event, one of the most spectacular sights up in the sky.

This month in history:

June 3: Gemini IV astronaut, Ed White, takes America’s first space walk – 1965
June 5: Regular observations of Neptune begun by Voyager 2 – 1989
June 13: Pioneer 10 leaves solar system to begin its interstellar voyage – 1983
June 16: Valentina Tereshkova first (and only solo) woman in space – 1963
June 21: First privately-funded human space flight, SpaceShipOne, is launched – 2004
June 30: Tunguska impact flattens hundreds of miles of Siberian forrest – 1908

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