Astronomy Israel: Earth

Showing posts with label Earth. Show all posts

Sunday, January 20, 2019

Total Lunar Eclipse in Israel, January 21, 2019

Early Monday morning, January 21, 2019, a total eclipse of the moon will be visible from Israel and most of the Western Hemisphere. Here are the timings of the eclipse in Israel:

Timings of the January 21, 2019 lunar eclipse. These timings are exact for Tel Aviv but virtually the same throughout the country.

This eclipse occurs very close to moonset and during dawn. Totality occurs just after moonset so a tiny sliver of the moon remains uneclipsed when the moon sets. Since the eclipse begins close to moonset you will need a very clear western horizon to view the event. Even better would be a high location with a clear horizon. In the East, Jupiter and Venus will be the bright pair of objects rising in the East, almost in conjunction with each other. (Actual conjunction will occur the next day, January 22, when the two planets are closest together in the sky.)

Since the moon will be so close to the horizon, the dense atmosphere may make it hard to see as the eclipse progresses and darkens. Binoculars will be useful in that situation.

The lunar eclipse begins at 4:36AM in Israel, with the moon setting in the Weat. This is an all-sky photo from the SkySafari Pro app.

Timings of the event are pretty close to those in Israel from everywhere in the world in Israel’s time zone which is GMT+2. You can look up your exact time and circumstances of the eclipse here: https://www.timeanddate.com/eclipse/lunar/2019-january-21

Selenelion

Because totality occurs at moonset (6:39am) in Israel a very rare event called a "Selenelion" may be visible. Sunrise is at 6:37am; total eclipsed moon sets at 6:39am. Celestial geometry says the sun and totally eclipsed moon should never be visible simultaneously in the sky, since the moon is eclipsed because it passes through the earth’s shadow with the sun opposite in the sky. But due to refraction caused by the earth’s atmosphere when objects are near the horizon, both the sun and moon appear higher in the sky than they actually are. Thus you can see them both at the same time, the sun rising in the east, the eclipsed moon setting in the west. You must be viewing an eclipse at just this right time, as occurs in Israel and other similar time zones during this eclipse to see a Selenelion.

Super Full Blood Wolf Moon

You may have read that this full moon (the moon can only be eclipsed when it is full with the earth between the sun and moon) is being called a Super Full Blood Wolf Moon. Kind of scary. In modern times a full moon at perigee, it’s closest approach to earth, has come to be called a Supermoon because it appears larger in the sky. (Actually only about 10% larger than a normal full moon). This is the first of three consecutive full Supermoons in 2019. Every full moon has a name from indigenous cultures and the Native Americans called the first full moon of January the Wolf moon, possibly because the wolves could be heard howling at it in the winter night. Eclipsed moons are frequently called “blood moons” because of the red color they take on when fully eclipsed, hence the name “Super Full Blood Wolf Moon”.

Now for the bad news. Skies are expected to be cloudy throughout Israel the morning of January 21. But you may still be able to see the eclipsed moon peeking out from between the clouds. Good luck!

Wednesday, July 11, 2018

Century's Longest Lunar Eclipse July 27, Tu B'Av!

The century's longest lunar eclipse is on Friday night July 27, Tu B'Av on the Jewish calendar. And lucky you if you live in Israel because you will have one of the best front row seats. Those living in the Americas and Canada, sorry! The eclipse ends before moon rise in your part of the world. So grab your best guy or gal, get an airplane ticket, and celebrate the Jewish night of romance with them under the totally eclipsed moon in Israel.

The chart below shows the timings and circumstances of the eclipse:

Timings and circumstances of the total lunar eclipse of July 27, 2018

Timings of the total lunar eclipse for Israel, with local Israel Daylight Times in parenthesis. In other words, the lunar eclipse begins at 9:24PM local time on Friday night, July 27, peak darkness is at 11:22PM on July 27, and ends at 1:19AM the morning of July 28.

2018 July 27

Partial eclipse begins: 18:24 UTC ( 21:24 Israel Daylight Time)

Total eclipse begins: 19:30 UTC (22:30 Israel Daylight Time)

Greatest eclipse: 20:22 UTC (23:22 Israel Daylight Time)

Total eclipse ends: 21:13 UTC (00:13 Israel Daylight Time)

Partial eclipse ends: 22:19 UTC (01:19 Israel Daylight Time)

This is such a long eclipse because as you will note from the chart above, the moon passes almost directly through the very center of the earth's shadow, its widest part, spending the longest time of the 21st century in eclipse! This is also a Micromoon full moon, the opposite of a Supermoon. A Micromoon full moon occurs when the full moon is at apogee, its greatest distance from the earth, so it appears smaller in the sky. Hence it also spends more time in the earth's shadow. Aren't we lucky to be alive on this date and living in Israel for a front row seat!

Take some time while watching the eclipse to note the moon's darkness, called its Danjon Number during an eclipse. 0 is darkest, 5 is brightest. When the moon passes centrally through the earth's shadow it's farthest from the edges of the shadow, so less sunlight gets refracted onto its surface during the eclipse. During some very dark eclipses the moon may completely disappear. But this also depends alot on the earth's atmosphere at the time. The denser or cloudier it is around the globe the more sunlight gets refracted onto the moon and the brighter the eclipse. This is hard to predict so it should be fun to look for how dark this eclipse is and estimate its Danjon number. You can find out more about the Danjon Scale here.

All lunar eclipses occur during full moon, when the moon is opposite the sun with the earth in between. July 27th's eclipse falls out on the full moon of the Jewish month of Av, or Tu (meaning 15) B'Av, often referred to as Jewish Valentine's Day, since on this day in ancient times the girls used to dress in their finest and dance in the fields to encourage matches with the boys. A happy time after the fast and mourning of the 9th of Av, Tisha B'Av. So, what could be better than going out with your Bestie to enjoy the romance of the longest lunar eclipse of the 21st century? I will leave it to the astrologers if this is a good or bad omen, the eclipse of the light of love or its revelation in the darkness of the moon. In any case this should not be one of those famous "blood red" moon eclipses since it is so central in the earth's shadow and little refracted sunlight, which causes the red color, should be evident. In any case be sure to take in all the planets that will be visible during the night, and especially during the darkness of totality. (See our previous post on the summer planets.)

You need no optical aid to the view a lunar eclipse but even small binoculars enhance the view and will show you details on the moon that are otherwise invisible to the naked eye.

There are many events being held to view the lunar eclipse in Mitzpe Ramon, but since this is a Shabbat night we will not be holding our usual star tour. You can look those events up online if you want to come down here. But a full moon and eclipse is usually so bright that you should be able to watch it from almost anywhere in Israel from the beaches of the Mediterranean to Diezengoff Square.
When I complained to a friend that the longest lunar eclipse of the century was falling on Shabbat and I wouldn't be able to hold a star tour, he told me, "Relax, it's Gd's way of telling you to just enjoy yourself for once." And so I shall. I hope you do,too!

To find out more about this eclipse see here.

Wednesday, January 7, 2015

What would the planets look like at the distance of our moon?

I love depictions of celestial bodies that show the vast difference in their sizes. Here's one of the planets in our solar system seen down the end of a dark highway if they were the same distance away as our moon, around 230,00 miles or 300,000km on average. Of course the gas giant planets, Jupiter, Saturn, Uranus and Neptune, have immense gravitational fields that would make short work of us on earth at that distance, but let's hold gravity in abeyance for a while while we contemplate the awesome difference in the size of the objects in our solar system.

Earth's moon and the planets of our solar system seen at the distance of the moon, 230,00 miles/300,000km

Monday, September 9, 2013

The New Moon with Venus, Spica and Saturn

I captured the close conjunction of the new moon of Tishrei with Venus last night, adding as a bonus the bright star Spica with Saturn entering the picture at the upper left towards the end.

Spica, the brightest star in Virgo appears just to the lower right of the moon with Venus above left. Towards the end of the animation Saturn enters the field at the top left.

New moon of September 8, 2013 with Venus to the upper left and Saturn to the far upper left. Around 8:00 PM above the hills of Mitzpe Ramon, Israel.

Sunday, September 8, 2013

Don't Miss Venus and the New Moon in the Evening Sky Tonight

Tonight, Sunday September 8, the new moon of Tishrei, just 3 days old, will make a beautiful pairing with Venus in the evening sky at sunset. Venus and the moon will be the two brightest objects in the sky, with Saturn visible above and to the left of Venus. If you have a completely clear western horizon and a pair of binoculars you should also be able to glimpse the elusive planet Mercury due west, above and to the left of the setting sun. But it will be very low in the sky and will set shortly after the sun. The other two planets and the moon will be visible well into darkness. On Monday night the moon will be above and left of Venus, not nearly as close, but still a pretty sight.

Give it a try and let us know what you see. Venus, Saturn and the moon are bright enough to be visible from even light polluted skies in Israel.

Venus will be visible just above and left of the moon, impossible to miss in the darkening sunset sky. Saturn should also be easy to see above and left of Venus, with Mercury a difficult binocular object above and just left of the setting sun. This view of the sky is for 7:00PM Local Israel Time on September 8, 2013.

Wednesday, December 22, 2010

The Blood Red Moon of December 20-21, 2010

The colors of the eclipsed moon yesterday were generally reported as "blood red", and Jewish tradition considers the color of an eclipsed moon to be a part of its "omen" value. What causes these colors which can range from very dark and barely visible to red or copper?

The earth's shadow is considerably larger than the diameter of the moon, so when the moon passes into that shadow (called the "umbra") becoming eclipsed, it can pass through the center of the shadow or on various paths above or below the center. Generally speaking, the more centrally the moon passes through the earth's shadow, the darker and less colorful the eclipse. The various paths the moon can take through the earth's shadow also account for variations in brightness seen across the disk of the moon.

Here is the path the moon took through the earth's shadow yesterday:

Path of the moon through the earth's shadow on December 20-21, 2010

The moon passed well north of the earth's umbra, the central and darkest part of its shadow, causing the moon's northern limb to appear much brighter than the southern.

The moon at mid-eclipse. (Tony Sharfman, Cranford, NJ)

Once the moon is in the umbra, the earth's atmosphere acts as a giant lens, bending the light of the sun around the earth and focusing it on the moon. Just as at sunset the long, red rays of the sun become enhanced because the thicker atmosphere scatters all of the shorter wavelengths, most of the light striking the moon is reddened by this atmospheric scattering and lensing. This effect can be enhanced or diminished by global weather effects along the rim of the earth, so the actual colors and brightness of an eclipsed moon are impossible to predict.