Government Shutdown Expands: Moon Goes on Furlough Tonight

In the above table, you can see the timing of tonight total eclipse of the Moon for all the North American time zones. Click on the image to see it bigger.

Don't worry about the first and last rows of the table. Just focus on when the partial eclipse begins (when the Earth's shadow first starts to move across the Moon) and when the total eclipse begins (the Moon is full covered by shadow and turns red.)

Remember, if there are clouds, this eclipse last a long time, so come back out after a few minutes and see if you can glimpse the Moon. Often the Moon plays hide and seek with layers of clouds, and patience will pay off.

Full details of the eclipse and what to watch for are here:
http://bit.ly/mooneclipse2019

Thanks to Sky & Telescope magazine for the table.  The composite photo below is by amateur astronomer and NASA educator, Brian Day.  Note the Earth's round shadow in the outer images and the coppery red color of the eclipsed Moon (the Earth's atmosphere bends red colors of light more effectively than other colors on to the shadowy face of the Moon.)

Heads Up: Total Eclipse of the Moon Sunday Evening January 20

On Sunday evening, January 20, there will be a nice total lunar eclipse (where the Earth’s shadow darkens the full moon) visible in all of North America. Since this is the day before Martin Luther King Day in the U.S., many students will not have school the next day and can stay up to enjoy the celestial spectacle with their families.

Total eclipses of the Moon are perfectly safe to look at, don’t require special viewing equipment, and are visible all over one hemisphere of planet Earth. Your eyes are just fine to see the show. This is quite a contrast with the total eclipses of the Sun, where viewing can sometimes hurt your eyes, special equipment is a big help, and the best show is only visible in a narrow path. As Bernie would say, the lunar eclipse is for the 99%, not just the special 1%!

A more detailed information sheet I put together (with questions and answers, plus the timing in each time zone of the continental U.S.) can be found at:
http://bit.ly/mooneclipse2019 

Here is wishing you a cloudless evening, and a few hours thinking about the heavens and not the craziness in Washington.

[Our beautiful photo is by Conrad Jung of the Chabot Space and Science Center, 2007]

North America to See An Eclipse of the Blue Moon January 31

On Wednesday morning, January 31, residents of North America (and particularly those on the west coast) will experience a rare triple event:

* The full moon will enter the Earth’s shadow and show a total eclipse (turning the full moon into a dark reddish disk)

* This will be the second full moon in the same month – something we call a blue moon

* And it will be a “supermoon,” where the Moon is full just as it’s closest to our planet Earth (this last thing by itself is not especially rare; in fact it will be third “supermoon” in a row).

Having all three together is unusual. The last time we had a blue moon totally eclipsed in the U.S. was more than 150 years ago.

Here are the times of the eclipse of the Moon on the morning of January 31 in different U.S. time zones:

Eclipse Circumstance                  Pacific Mountain Central Eastern

Partial eclipse begins                 3:48 am 4:48 am 5:48 am 6:48 am
Total eclipse begins                   4:52 am 5:52 am 6:52 am ---
Total eclipse ends                      6:08 am 7:08 am ---         ---
Partial eclipse ends                    7:11 am ---         ---         ---

--- means that Moon has already set (is below the horizon)

You can see that in the eastern half of the U.S., the full Moon sets before the total eclipse or just as the eclipse is getting good, but in the western half of the U.S., some or all of the eclipse will be ready to delight those who can get up early (before the Sun does) that morning.

If you are planning to get up to see the last part of the total eclipse, there is one other factor to keep in mind. The eclipsed Moon is setting in the west as the Sun is rising in the east. That means you have to have a clear sight-line toward the western horizon for the eclipse. If buildings or trees block your view in that direction, you could miss the event. So scout out the location where you plan to be in advance. (Maps and charts can be seen at: http://www.skyandtelescope.com/obser…/january-lunar-eclipse/ )

Note: Only the total eclipse turns the Moon an eerie dark red (because of the bending of red light in the Earth’s atmosphere.) Once the total eclipse is over, the reddish effect that eclipse fans like (and the media call a "blood moon") will be gone.

Our remarkable photo, by Elias Politis, shows a 2011 lunar eclipse sequence over the Acropolis in Greece. Click on the image to see it larger.

A Total Eclipse of the Moon Sunday Evening September 27

I thought you might like advance notice of a very nice upcoming lunar eclipse visible next Sunday evening in North and South America and in the early morning in Europe and parts of Africa and west Asia. Below are the basics in the form of questions and answers.  All you need to enjoy the eclipse is clear skies and (on the American west coast) an unobstructed view toward the East.

Next week you will start reading media reports about this being both a “blood moon” and a “supermoon,” but don’t pay too much attention to that.  The Moon will be a bit closer to the Earth in its orbit than average, making it look a bit bigger, but the difference is not especially significant.  And every lunar eclipse could turn reddish, as explained below.  It’s rarely the color of blood, but the media love anything that can be connected to thoughts of violence.

The Sept. 27, 2015 Total Eclipse of the Moon

1. What Is Happening?

On Sunday evening Sept. 27, a total eclipse of the Moon will be visible from throughout the U.S. (and North and South America.) In a lunar eclipse, the full Moon & the Sun are exactly opposite each other in our sky, and the Earth gets between them. This means the Earth’s shadow falls on the full Moon, darkening it.  It’s a nicely democratic event; no special equipment is needed to see it (provided it’s not cloudy or foggy.) Plus it happens early in the evening; kids can watch & still be awake for school next day.

2. When Will the Eclipse Happen?

The table below is for the U.S. (for other countries and continents, see: http://www.timeanddate.com/eclipse/lunar/2015-september-28  which can be set for your home location.) 

Event	Pacific	Mountain	Central	Eastern
Partial eclipse starts	Moon not up	7:07 pm	8:07 pm	9:07 pm
Total eclipse starts	7:11 pm	8:11 pm	9:11 pm	10:11 pm
Total eclipse ends	8:23 pm	9:23 pm	10:23 pm	11:23 pm
Partial eclipse ends	9:27 pm	10:27 pm	11:27 pm	12:27 am

As Earth’s shadow slowly moves across the Moon, we first see only part of the Moon darkening (partial eclipse).  When our shadow completely covers the Moon, we see a total eclipse. The best time to start watching is about a 20 minutes before total eclipse begins, when much of the Moon is already darkened. 

NOTE: On the west coast, the eclipse will start low in the Eastern sky, so make sure your observing location has an unobstructed view toward the Eastern horizon.

3. What is Visible During a Lunar Eclipse?

As the shadow of the Earth covers the Moon, note that our natural satellite doesn’t become completely dark.  Some sunlight bent through the Earth’s atmosphere still reaches the shadowed Moon and gives it a dull brown or reddish glow.  The exact color of the glow and its darkness depend in part on the “sooty-ness” of our atmosphere – how recently volcanoes have gone off and how much cloud cover, storm activity, and human pollution there is around the globe. 

Once the Moon is totally eclipsed, the stars in the sky should become more easy to see.  What makes this eclipse a little bit unusual is that, by coincidence, it is happening just one hour after the Moon has reached the closest point in its monthly orbit around the Earth.  So the Moon will look a bit larger in the sky than usual.  (The media will be calling it a “supermoon,” but the effect is pretty subtle for the average person.)

4. Is it Safe to Watch, and How do I Watch?

Since the Moon is safe to look at, and eclipses make the Moon darker, there’s no danger in watching the eclipse with your eyes or a telescope.  (The dangerous eclipse is the solar one, where it is the Sun that gets covered.) And lunar eclipses don’t require you to go to a dark location.  Bring binoculars to see the Moon larger, but just your eyes are fine.  Since the total eclipse will last for an hour and 12 minutes, be sure to take someone along with whom you like to spend time in the dark!

5. What Can I Tell My Kids (or Kid Brother or Sister)?

Suggest that they take a careful look at the shadow of the Earth as it moves across the bright face of the Moon.  What shape is it?  The round shape of the Earth's shadow suggested to the ancient Greeks, more than 2000 years ago, that the Earth’s shape must be round too.  Eclipse after eclipse, they saw that the Earth cast a round shadow, and deduced that we lived on a round planet (long before we had pictures of it from space.)

Happy Fall Equinox on Monday and Other Sky Events

Monday morning (Sept. 22) is the "autumnal" or fall equinox for those of us in the Northern Hemisphere. On that day, the length of the day and the night are roughly the same ("equinox" means equal night). We are moving from the summer, when the days were longer, toward the winter when our nights are longer -- and our parts of the planet have fewer hours to heat up from sunlight.

The equinox is sometimes called the official start of fall and throughout history there have been festivals and beginnings celebrated at the time. It so happens that Foothill College, where I teach, starts its fall quarter on the equinox this year, so I will be welcoming several hundred new students to my classes with a happy equinox greeting (and many who don't know the term will be looking at me as if I were a crazy person!)

The fall quarter will bring many interesting events to fans of astronomy. Tonight, Sunday, the MAVEN spacecraft will be inserted into orbit around Mars, so it can begin to study how little Mars, with its lower gravity, lost its atmosphere over the millennia, and how its remaining air layers interact with the radiation and wind from the Sun.

October 8th, we will have a total eclipse of the Moon (these are much more common than total eclipses of the Sun.) Alas, for those of us in North America, this will be a middle of the night eclipse! The full Moon will go dark as the Earth's shadow falls on it, but most of us will be in bed, deeply asleep, when it happens. For example, in San Francisco, the eclipse happens from about 2:30 am to 5:30 am, so only dedicated night owls will be watching it. (If you miss it, don't worry, there will be two lunar eclipses visible in 2015.)

On October 19th, a newly discovered comet will come closer to the planet Mars than any known comet has come to Earth, and so our robot "representatives" around Mars will be keeping their cameras out for that pass.

On October 23rd, in the afternoon, much of North America will witness a partial eclipse of the Sun in the afternoon. Many astronomy organizations will be planning eclipse parties, with safe viewing options. I will do a full post about the eclipse when we get closer to the time.

And, down on Earth, October 25th, the opening day of the 2014 Bay Area Science Festival, I will be giving a free public talk on Mt. Tamalpais about the "Top Tourist Sights of the Solar System: Where Bill Gates' Great-Granddaughter will go for Her Honeymoon." See: http://wonderfest.org/top-tourist-signs-of-the-solar-system/

What Would the Lunar Eclipse Have Looked Like from the Moon?

We who live in North or South America (and had clear skies,) experienced a total eclipse of the Moon Tuesday morning, April 15.  But what would the eclipse have looked like to someone on the Moon?

First, since the Moon always keeps one side toward the Earth and one side away from the Earth, we have to pick a side. For this purpose, the interesting side of the Moon is the one that was facing the Earth and the Sun. It was sunny and bright on that side of the Moon before the eclipse began. Then, an observer on the Moon would have seen the Earth move in front of the Sun, and darkness descend. It would have gotten colder too without the warmth of the Sun.

Since the nearby Earth looks bigger from the Moon that the Sun does, the Earth more than covered the Sun. Still, the Earth's atmosphere bends some of the sunlight behind it toward the Moon. So someone on the Moon would have seen a faint ring of light around the dark Earth. (If you had a telescope on the Moon, you might also have seen the lights of big cities and large fires on the night side of our planet.)

How do we know that this "Moon perspective" about the eclipse is right? A Japanese spacecraft called Kaguya captured just this kind of image during a lunar eclipse in February 2009, as it was orbiting the Moon. In the picture above (courtesy of the Japanese Space Agency), you see several views of the Earth from the Moon during the eclipse. The ring of light is not complete, because some part of Earth was below the Moon's horizon as seen by Kaguya. At the end of the eclipse, you can see the first light of the Sun coming out from behind the Earth, making a kind of diamond ring effect. How wonderful that our robot spacecraft can give us views in the solar system that earlier scientists could only imagine!

Apr. 14-15, 2014 Total Eclipse of the Moon Visible Throughout North America

I've put the information about this eclipse in question-and-answer format:

1. What Is Happening?

               Late on Monday evening and early Tuesday morning, Apr. 14-15, a total eclipse of the Moon will be visible from throughout the U.S.  In a lunar eclipse, the full Moon and the Sun are exactly opposite each other in our skies, and the Earth gets between them. This means that the Earth’s shadow falls on the Moon, darkening it.  (See the diagram above.) This will be a nicely democratic event; the eclipsed Moon will be high in the sky and easily visible (provided it’s not cloudy.)

2. When Will the Eclipse Happen?

Event	Pacific	Mountain	Central	Eastern
Partial eclipse starts	10:58 pm	11:58 pm	12:58 am	1:58 am
Total eclipse starts	12:07 am	1:07 am	2:07 am	3:07 am
Total eclipse ends	1:25 am	2:25 am	3:25 am	4:25 am
Partial eclipse ends	2:33 am	3:33 am	4:33 am	5:33 am

As the shadow of the Earth slowly moves across the Moon, we first see only part of the Moon darkening (partial eclipse).  When the Earth’s shadow completely covers the Moon, we see a total eclipse, weather permitting.  

The best times to watch probably start a half hour before total eclipse starts, by which time a substantial part of the Moon is eclipsed.  The whole total phase lasts 78 minutes this time, and it looks pretty much the same the whole time, so only the most dedicate eclipse buffs will stay up for the whole thing.

3. What is Visible During a Lunar Eclipse

               As the shadow of the Earth covers the Moon, note that our natural satellite doesn’t become completely dark.  Light bent through the Earth’s atmosphere still reaches the shadowed Moon, and gives it a dull brown or reddish glow.  The exact color of the glow and its darkness depend on the “sooty-ness” of our atmosphere – how recently volcanoes have gone off and how much cloud cover, storm activity, and human pollution there is around the globe.

               Also, as the Moon becomes dark, other things in the night sky become easier to see.  As you look toward the southwest, you can see Mars to the right of the Moon, the bright star Spica just below and near it, and Saturn off to the left. Here is a nice diagram from Astronomy magazine (click to make it bigger). 

(Note that this is drawn for 3 am Central Time, which is 1 am Pacific Time.)

4. Is it Safe to Watch, and How do I Watch?

               Since the Moon is safe to look at and eclipses make the Moon darker, there’s no danger in watching the eclipse with your eyes or a telescope.  (The more dangerous eclipse is the solar one, where it is the Sun that gets covered.) Lunar eclipses don’t require you to have fancy equipment or to go to a dark location.  Bring binoculars, if you have them, to see the Moon larger, but just your eyes are fine.  Take someone along with whom you like to spend time in the dark!

5. What Can I Tell My Kids (or Kid Brother or Sister)?

               Suggest that they take a careful look at the shadow of the Earth as it moves across the bright face of the Moon.  What shape is it?  The round shape of the Earth's shadow suggested to the ancient Greeks, more than 2000 years ago, that the Earth’s shape must be round too.  Eclipse after eclipse, they saw that the Earth cast a round shadow, and deduced that we lived on a round planet (long before we had pictures from space.) 

Also, if kids have to miss this eclipse, you can console them by letting them know that there will be another total lunar eclipse on Oct. 8^th, 2014 (and two more in 2015.)