Weird auroras / Mercury meets a dainty moon / See 5 evening planets!

An oval patch of glowing green aurora appeared in the northern sky in Cassiopeia last night (April 17). Credit: Bob King

An oval patch of glowing green aurora pulses in Cassiopeia last night (April 17). Credit: Bob King

It’s been a fantastic 4 nights of northern lights. For now, Earth’s magnetic environment has returned to quiet conditions. Similar to the run of auroras that began on St. Patrick’s Day, this one finished with the same peculiar, sausage-shaped patches.

Last night I noticed a single elongated glow about two fists across in the northern sky in late twilight that slowly pulsed in brightness, often disappearing for 10-15 seconds and then reappearing in the same spot. Like breath on a mirror.

Another view of the diffuse aurora seen last night across the northern sky. Credit: Bob King

Another view of the diffuse aurora seen last night across the northern sky. Credit: Bob King

During the night, the patch slinked slowly westward into Cassiopeia and then disappeared altogether around 11 o’clock. At midnight it reappeared in the northeastern sky below the Northern Cross.  The strange apparition added quiet intrigue to the evening’s boisterous calls from the frogs.

Use bright Venus to help point you in the right direction. This map shows the sky facing west-northwest around 40 minutes after sunset. Created with Stellarium

Use bright Venus to help point you in the right direction. This map shows the sky facing west-northwest around 40 minutes after sunset. Mercury is 7° to the lower right of the moon. Created with Stellarium

Tomorrow night (April 19), look to the northwest about 40 minutes after sunset for a rare alignment of a day-old moon and two planets. One of them, Mars, has been around since last spring. Back then it was much closer to Earth and brilliant. Since then the two planets have separated with Mars now far away and rather faint. You wouldn’t ordinary seek it out so low in a bright sky, but the youthful crescent moon will certainly lure you there.

Mercury's approximate path and altitude during its dusk appearance this spring. Notice how its phase changes from the current gibbous to half to crescent. Source: Stellarium, Bob King

Mercury’s approximate path and altitude during its dusk appearance this spring. Notice how its phase changes from the current gibbous to half to crescent. Source: Stellarium, Bob King

The moon will be just a bit more than one day old and appear as a razor-thin sliver about 5-7° high (three to four fingers held at arm’s length). It should be easily visible from anywhere with a wide open view to the west-northwest. Because of its relative faintness, Mars will probably require binoculars to see. Focus on the moon first and then slide to the right to find the star-like planet.

As an inner planet, Mercury goes through phases just like Venus and the Moon. We see it morph from crescent to “full moon” as its angle to the Sun changes during its revolution of the Sun. Credit: ESO

As an inner planet, Mercury goes through phases just like Venus and the Moon. We see it vary from crescent to “full moon” as its angle to the Sun changes during its revolution of the Sun. Credit: ESO

Mercury shines at magnitude -0.5, even brighter than Vega or Arcturus, but it’s only a few degrees high, so you might need binoculars to see it, too. Once again, the moon comes to the rescue. Look either with your eyes or binos 7° (four fingers) to its lower right.

Mercury quickly moves up from the horizon in the next two weeks for its best evening appearance of the year for northern hemisphere skywatchers. As it comes into better view, the planet will slowly fade and change phase just like the moon. You can see the phases through a small telescope magnifying about 75x. Be sure to look for Mercury early when it’s highest or the blurring effect of the atmosphere will turn it into a ball of quivering mush.

Saturn pops up in the head of the Scorpion in late April around 11-11:30 p.m. This photo was taken early this morning just after midnight. Credit: Bob King

Saturn pops up in the head of the Scorpion in late April around 11-11:30 p.m. This photo was taken early this morning just after midnight. Credit: Bob King

With Mercury joining the scene, we now have five — count ‘em — five planets visible in the evening sky. Throw in the Earth and that makes six out of a total of eight! Mercury and Mars hang low in the west; Venus can’t be missed, shining like a lighthouse high in the west at dusk; Jupiter dominates the southern sky in Cancer and if you stay up till 11:30, you’ll see Saturn rise in Scorpius low in the southeastern sky.

Such riches for planetary enthusiasts. Go out and meet your solar system at the next opportunity.

A moon rock lands in Duluth

Chelsea Paulson, 5, of Saginaw, holds her grandfather Randy Paulson's hand as she studies the Apollo moon rock inside a lucite pyramid at NASA's Journey to Tomorrow traveling exhibit at the Home Show at the DECC Thursday evening. The rock (seen in the inset at upper left) was collected by Apollo 17 astronauts Gene Cernan and Harrison Schmitt in December 1972. It's about 3 inches across, weighs 152 grams (1/3 lb.) and is 3.9 billion years old. Credit: Bob King

Chelsea Paulson, 5, of Saginaw, holds her grandfather Randy Paulson’s hand while looking at the Apollo moon rock inside a lucite pyramid at NASA’s Journey to Tomorrow traveling exhibit at the Home Show in Duluth, Minn. Thursday. The rock was collected by Apollo 17 astronaut Gene Cernan in December 1972. Credit: Bob King

A priceless moon rock lies locked in a glowing pyramid of lucite a few blocks from Lake Superior in Duluth today. NASA’s “Journey to Tomorrow” traveling exhibit pulled into town a few days ago, and among the displays is a palm-sized lunar rock collected by Apollo 17 astronaut Gene Cernan sometime on December 13,1972.

Closer view of the 152 gram polycrystalline moon rock returned from the moon during the Apollo 17 mission to the Taurus-Littrow highlands. Credit: Bob King

Closer view of the 152 gram polycrystalline moon rock returned from the moon during the Apollo 17 mission to the Taurus-Littrow highlands. Credit: Bob King

The 152 gram (1/3 lb.) concrete-gray rock measures about 3 inches (7.6 cm) across. It was part of a larger rock picked up by Cernan on his third moonwalk with fellow astronaut Harrison Schmitt. Moon-drive might be a better description. The two boarded the Lunar Rover that Wednesday evening and drove 2.5 miles (4 km) northeast of their landing site in Taurus-Littrow Valley, a relatively smooth area snaking between the rugged peaks of the Taurus Mountains just beyond the lava plains of the Sea of Serenity.

Astronauts often used tongs to pick up lunar samples. It was a lot easier than bending over in bulky space suits to pick up a rock. The rock in the NASA exhibit was likely collected this way. Credit: NASA

Astronauts often used tongs to pick up lunar samples. It was a lot easier than bending over in bulky space suits to pick up a rock. The rock in the NASA exhibit was likely collected this way. Credit: NASA

During one of their stops to collect samples, Cernan’s curiosity must have been peaked by the rock’s appearance. Using a set of tongs (or possibly a hammer to bust a chip off a larger formation), he retrieved the sample and dropped it in a bag. Schmitt and Cernan later placed the bags into specially sealed storage boxes and loaded them — along with our featured rock — into the lunar module ascent stage for the trip back to lunar orbit and Earth.

After Apollo 17 safely landed, the boxes were taken to the Lunar Receiving Laboratory at the Johnson Space Center near Houston, Texas and opened in a vacuum chamber to avoid contamination by the atmosphere. Before our 152 gram “rock star” began its 50-state tour, it was sliced (hence the smooth face on one side), classified and its age determined by radioactive dating methods.

This is as close as I could get to the moon rock. Not only was it contained in lucite, it was also in a glass case. You can easily see cracks formed by impact bombardment as well as tiny holes or vesicles where gases escaped when the rock was melted and or re-heated during an impact. Credit: Bob King

This is as close as I could get. Not only was the rock contained in lucite, it was behind glass. You can easily see cracks and melt veins formed by impact bombardment as well as tiny holes or vesicles where gases escaped when the rock partially melted an impact. Credit: Bob King

It looks so ordinary to the eye. Like I said, a gray rock. I’ve seen better tossed up by the waves of Lake Superior. But before you lies a 3.9 billion-year-old stone far older than most Earth rocks.

The outside of the moon rock is darker than the inside. This is probably caused by "space weathering" or radiation and high-speed particles from the Sun that slowly darken the moon's surface over time.  Credit: Bob King

The outside of the moon rock is darker than the inside. This is probably caused by “space weathering” – radiation and high-speed particles from the Sun that slowly darken the moon’s surface over time. Younger craters on the moon are much brighter than older because the impacts plow up dust and debris from under the surface that haven’t be exposed to the Sun for millions or billions of years. Credit: Bob King

Here in Duluth, we admire the tough 1.1 billion-year-old lava formations that tower above the waves of Lake Superior and underlie the region for miles. Ancient for sure, but the traveling moon rock provides a fresh perspective on exactly how old is old. It solidified just 400 million years after the moon itself took shape from the debris released during the cataclysmic impact of a Mars-sized planet with Earth.

This is the traveling moon rock's home base - the Apollo 17 landing site,  photographed  by the Lunar Reconnaissance Orbiter. Click for a larger view. Credit: NASA

This is the traveling moon rock’s home base – the Apollo 17 landing site, photographed by the Lunar Reconnaissance Orbiter. Click for a larger view. Credit: NASA

The display next to the sample describes it as a “polycrystalline breccia” or rock composed of many older crystalline rocks melded together. The vast majority of rocks gathered by the Apollo astronauts are rock fragments or breccias cemented together through impact. Is it any surprise? The early moon was a devil’s playground of non-stop bombardment by meteoroids and asteroids. Each impact crushed and re-mixed the crustal rocks, creating oodles of fragments. Breccia within breccia.

Check out the melt veins, cracks and vesicles (little holes) in the cut face — all indications of the violence that visited not only the moon but all the planets and moons during the solar system’s formative years.

Apollo 17 astronaut Eugene Cernan checks out the Lunar Rover before he and Harrison Schmitt head out for another moonwalk. On the day our featured rock was found, the astronauts collected 146 pounds of lunar samples. Credit: NASA

Apollo 17 astronaut Eugene Cernan checks out the Lunar Rover before he and Harrison Schmitt head out for another moonwalk. On the day our featured rock was found, the astronauts collected 146 pounds of lunar samples. These were the last rocks to date brought back from the moon by the United States. Credit: NASA

You can see all this history wrapped up in a single rock with your own eyes still today. The big NASA truck with the moon rock and other space-themed exhibits will be open through 5 p.m. today (April 12) at the annual Home and Builder Show at the Duluth Entertainment Convention Center (DECC). If you can’t make it, the traveling exhibit may be coming to a town near you, although they don’t have a set schedule. For more information, click HERE.

Apollo landing sites. Apollo 17's location is highlighted in red. Credit: Soerfm

Apollo landing sites. Apollo 17’s location is highlighted in red. Credit: Soerfm

Moon turns red as Earth turns to face the morning Sun

The eclipsed (but overexposed) moon reflected in Superior Bay on Park Point in Duluth, Minn. early during the partial phase. Credit: Bob King

The eclipsed (but overexposed) moon reflected in Superior Bay on Park Point in Duluth, Minn. early during the partial phase. Credit: Bob King

I love eclipses and still find it amazing we can predict them with such accuracy. We saw a beauty earlier today, the third of the tetrad that will wrap up with the September 28th total eclipse.

The few clouds that did pester the moon added a scenic touch. Credit: Mike Sangster

The few clouds that did pester the moon added a scenic touch. Credit: Mike Sangster

Many eclipse watchers stood at the pivot of the celestial seesaw this morning. As dawn bloomed at our backs, the moon teetered toward the western horizon. We were fortunate the sky cleared for a good view of the lunar eclipse here in Duluth, Minn.

My eagle-eyed daughter Maria and I easily saw the late penumbral phase — when the moon passed deepest in Earth’s outer shadow — as a brownish stain or soiling of the eastern half of the moon around 4:55 a.m. Promptly at 5:16 a.m., our satellite crossed into Earth’s dark inner shadow or umbra and the partial eclipse began.

Since the eclipse happened in a brightening dawn sky, the orange moon is set off against blue in this photo taken through a small refracting telescope. Credit: Bob King

Since the eclipse happened in a bright dawn sky, the orange moon is steeped in blue in this photo taken through a small refracting telescope. Credit: Bob King

Lunar eclipses are generally leisurely affairs, so our group of moongazers had time to take pictures, look through telescopes and watch the moon turn red in a blue sky. We observed from Park Point, the largest freshwater sand bar in the world. With water close at hand, ducks, geese, loons and song sparrows chattered, sang and honked, unconcerned about the eclipse.

A slice of moon pokes out of the clouds move in. Credit: Bob King

A slice of moon pokes out as clouds move in. Credit: Bob King

In the western U.S., parts of Asia and Australia, the moon briefly dipped fully inside the Earth's shadow in total eclipse. The bright upper edge in this photo was closest to the outer edge of the shadow. Credit: Soma Acharya

In the western U.S., parts of Asia and Australia, a brief total eclipse was visible. The upper edge of the moon was closest to the outer edge of the shadow and appears brighter in this photo taken from Napa, Calif. Credit: Soma Acharya

Using binoculars, we could see the sunset orange of the moon’s disk when it had eased about a third of the way into Earth’s shadow. Somewhere around halfway, you could see color dimly with the naked eye.

Jim Schaff of Duluth composes a photo of the eclipsed moon over Superior Bay early Saturday morning. Credit: Bob King

Jim Schaff of Duluth composes a photo of the eclipsed moon over Superior Bay early Saturday morning. Credit: Bob King

Shortly before moonset, distant clouds minced the moon into slivers and finally devoured it altogether, a sign we interpreted as time for breakfast.

The eclipse crew. From left: Karl, Jim, Mike, my daughter Maria, me, Rick, Ron and Michael. Many of us belong to the Arrowhead Astronomical Society of Duluth. Credit: Eric Norland

The eclipse crew. From left: Karl, Jim, Mike, my daughter Maria, me, Ron, Rick and Michael. Many of us belong to the Arrowhead Astronomical Society of Duluth. Credit: Eric Norland

After way too many jokes about the bacon-y color of the deeply-eclipsed moon, we drove to a nearby restaurant and sat down for conversation, coffee and laughs. When the meals arrived, several of our group couldn’t resist bending bacon strips into the shapes of shadowed crescents to celebrate a fantastic morning.

Bacon in the shape of the eclipsed moon for breakfast. Credit: Bob King Bacon in the shape of the eclipsed moon for breakfast. Credit: Bob King

Bacon in the shape of the eclipsed moon for breakfast. Credit: Bob King

The full moon Friday night April 3 - the stage upon which this morning's wonderful eclipse played out. Credit: Bob King

The full moon Friday night April 3 – the stage for this morning’s wonderful total lunar eclipse. Eclipses are infrequent enough, so having clear skies to see one is a rare event. Credit: Bob King

Don’t miss Saturday’s ‘Blood Moon’ eclipse

The totally eclipsed moon from April 15, 2014. This was the first in the series of four eclipses called a tetrad. Credit: Bob King

The totally eclipsed moon on April 15, 2014 from Duluth, Minn. This was the first in the series of four eclipses called a tetrad. Some refer to this lunar eclipse as a “Blood Moon” because it coincides with the Jewish Passover. Credit: Bob King

Doing anything this weekend? The third in a series of four total lunar eclipses happens early Saturday morning across North and South America, Hawaii, Asia and Australia. If you live in the eastern half of the U.S. and Canada however, this will be a partial eclipse with the moon setting before totality.

Bacon could be an option after watching Saturday's dawn eclipse. Credit: Bob King

Bacon could be an option after watching Saturday’s dawn eclipse. Credit: Bob King

There’s nothing like the bacon-colored eclipsed me to get you thinking about breakfast. Weather permitting, my friends and I hope to watch the event together and then make a beeline for breakfast at sunrise. The timing couldn’t be better.

When four total lunar eclipses occur in a row with no partials in between, it’s called a tetrad. We’re three-quarters through the current tetrad with the final of the four slated for September 28 this year. Tetrads can be relatively common, as they will be this century with the maximum of eight, or rare, as they were during the 300 year period between 1600 and 1900, when there were exactly zero.

When Sun, Earth and full moon all lie in a straight line, the moon moves directly behind Earth and into its shadow, making for a lunar eclipse. Because of the moon's tilted orbit, most full moons miss the shadow, but several times a year, the alignment is just right and we get an eclipse.

When Sun, Earth and full moon all lie in a straight line, the moon moves directly behind Earth and into its shadow, giving us a lunar eclipse. Because of the moon’s tilted orbit and the small size of Earth’s shadow at the moon’s distance (just 1.4°) the moon misses the shadow, but several times a year, the alignment is exact and we get an eclipse.

Lunar eclipses happen when the Sun, Earth and full moon all lie in a straight line. The moon moves into the two-part shadow cast by the Earth and we see an eclipse. Because the moon’s orbit is tilted about 5°, it usually misses the shadow during most full moons or only passes through the outer part for a partial eclipse.

Earth’s shadow is composed of two nested components – the inner umbra, where the Earth completely blocks the Sun from view, and an outer penumbra, where the planet only partially blocks the sun. Because the penumbra is a mix of shadow and sunlight, it’s nowhere near as dark as the umbra. You can see the slight penumbral shading beginning about a half hour before partial eclipse and up to a half hour after it ends.

Animation showing the moon's path through Earth's shadow on April 4th. Credit: Tom Ruen

Animation showing the moon’s path through Earth’s shadow on April 4th. Credit: Tom Ruen

Saturday’s eclipse is unusual because the moon only barely makes it inside the umbra with totality lasting just under 5 minutes. Partial phases, which begin when the moon first touches the umbra and end when it departs, are far more generous, lasting better than 3 1/2 hours.

If you live in the eastern U.S. along the coast, the moon will only be 10-20% covered in Earth’s shadow near the time it sets in morning twilight. That fraction increases to 50-75% or more for the Midwest. Totality occurs in morning twilight shortly before moonset in the mountain states, while lucky West Coasters will see the fully eclipsed moon in dark sky. Hands down, Hawaii’s the best place to see it for obvious reasons but also because you’ll be able to watch the entire event in a dark sky.

Map showing where the eclipse visibility across the U.S. and Canada. West of a line running through western Minnesota, Iowa, Missouri, Arkansas and Louisiana, skywatchers will see a total eclipse before moonset. Inset map shows worldwide visibility. Credit: Larry Koehn / shadowandsubstance.com. Inset: Fred Espenak

Map showing eclipse visibility across the western hemisphere. West of a line running through western Minnesota, Iowa, Missouri, Arkansas and Louisiana, skywatchers will see a total eclipse before moonset. Inset map shows worldwide visibility. Credit: Larry Koehn / shadowandsubstance.com. Inset: Fred Espenak

To see the eclipse at its best, whether that be partial or total, find a spot with a clear view to the southwest. For much of the U.S., the moon will be dropping down toward the southwest horizon during morning twilight. The moon begins the night before as full, but when you get up before dawn on Saturday, you’ll see a bite taken out of it. That bite grows bigger as the moon drops closer to the horizon.

For much of the Midwest, the moon will appear half to two-thirds eclipsed low in the southwestern sky in a bright dawn sky. This is the view from Chicago at 6:15 a.m. with the moon just 3 high. Created with Stellarium

For much of the Midwest, the moon will appear half to two-thirds eclipsed low in the southwestern sky in a bright dawn sky. This is the view from Chicago at 6:15 a.m. with the moon just 3° high. Created with Stellarium

Given its low altitude and the light of dawn, this will be a perfect opportunity to photograph the eclipse against a landscape or skyline. Even a mobile phone will be able to handle the challenge — go for it!

One fun thing to watch for during the event, especially where totality is visible in a dark sky, is the return of darkness and a starry sky. The color of the moon is also a variable. Sometimes it’s bright copper orange, others time smoky brown depending on the amount of particulates like salt, water and volcanic dust suspended in the atmosphere. This should be a bright totality if only because the moon passes just within the umbra’s edge.

Phases of a lunar eclipse leading to totality (right). Credit: Jim Schaff

Phases of a lunar eclipse leading to totality (right). Credit: Jim Schaff

You’d think the moon would disappear when it slid into Earth’s shadow. Hardly. If we had no atmosphere it would, but that thin layer of air filters the sunlight grazing the planet’s edge and colors it red and orange just like a sunset or sunrise. The atmosphere also acts like a lens and bends or refracts the red light directly into the shadow, coloring the moon.

This diagram shows how the moon moves through Earth's shadow during the eclipse. Times are Central Daylight (Midwest, central Canada and Mid-South). Credit: Fred Espenak

This diagram shows how the moon moves through Earth’s shadow during the eclipse. Times are Central Daylight (Midwest, central Canada and Mid-South). Because the Sun rises around 6:30-45 a.m., totality won’t be visible in the central part of the country. Credit: Fred Espenak

I like to imagine standing on the lunar surface, bathed in red during the eclipse, looking back toward Earth eclipsing the Sun. Seen from this perspective, Earth wears a marvelous collar of sunrise-sunset light.

Seen from the moon, a total lunar eclipse becomes a total solar eclipse with the Earth eclipsing the Sun. Notice the Earth's red rim. Created with Stellarium

Seen from the moon, a total lunar eclipse becomes a total solar eclipse with the Earth eclipsing the Sun. Notice the Earth’s red rim. Created with Stellarium

For more cool stuff to see during this eclipse, click HERE. The diagram above shows the CDT or Central Daylight viewing times. Click below for others:

* Eastern Daylight time diagram
* Mountain Daylight time diagram
* Pacific Daylight time diagram
* Alaska Daylight time diagram
* Hawaii Daylight time diagram

For skywatchers in the eastern half of the country to make the most of the eclipse, it helps to know the time the sun rises for your town. Plan to be out at least an hour and a half before that to catch the show.

For observers either not in the eclipse zone or unfortunately clouded out, you can watch it online at SLOOH and the Virtual Telescope Project. If you do take any pictures of the shadow-dipped moon, please send them to me at rking@duluthnews.com and I’ll put up a gallery later Saturday morning … after I finish breakfast. Good luck and enjoy!

Largest recorded explosion on moon excavates 60-ft. crater

Simulation of the flash of impact on March 17, 2013 when a boulder-sized meteorite excavated a 59-foot-wide crater in the moon's Mare Imbrium. Credit: NASA

Simulation of the flash of impact on March 17, 2013 when a boulder-sized meteorite excavated a 59-foot-wide crater in the moon’s Mare Imbrium. Credit: NASA

Two years ago March 17 an object the size of a small boulder hit the surface of the moon in Mare Imbrium and exploded in a flash of light nearly 10 times as bright as anything ever recorded before. Mare Imbrium is a lunar “sea” that forms the left eye in the Man in the Moon face we see at full moon.

NASA video of the meteorite impact that created a new moon crater

The impact and explosion were recorded with a video camera at NASA’s Marshall Space Flight Center. Based on the brightness of the flash, scientists determined a space rock about a foot wide struck the lunar surface, big enough to hollow out a substantial crater. After pinpointing the impact’s coordinates, the information was relayed to NASA’s Lunar Reconnaissance Orbiter (LRO) team, which then directed the probe to take pictures of the area in hopes of finding a fresh impact scar.

Illustration of the pattern of rays the LRO team discovered which led them to the new crater. Credit: NASA

Illustration of the pattern of rays the LRO team discovered which led them to the new crater. Credit: NASA

Nothing was found at first because the low resolution video images didn’t allow for precision targeting. So the team broadened their search to adjacent swaths of terrain. After several attempts, they noticed something unusual – streaks that looked like faint rays. Could it be part of a classic blast pattern left by impact debris showering down on the moon’s surface?

The new moon crater carved out by a meteorite strike last March 17 measures about 62 feet across. A faint blast pattern surrounds it. Credit: NASA

The new moon crater carved out by a meteorite strike last March 17 measures about 62 feet across. A faint blast pattern extends outward from its rim. Credit: NASA

They did the logical thing and traced the rays back to their convergence point. When the LRO was directed to photograph the new coordinates, immediately a fresh, new crater at the center of that pattern was revealed in photographs sent back to Earth.

This image pairing shows a lunar impact crater created on March 17, 2013. The two images are from the LROC instrument aboard NASA's Lunar Reconnaissance Orbiter. The left image is from Feb. 12, 2012, and the right image is from July 28, 2013. The new crater is about 59 feet wide. Click and drag the slider bar to swipe between the two images. Image Credit: NASA/Goddard Space Flight Center/Arizona State University

This paired photos taken by the LRO show a lunar impact crater created on March 17, 2013. The left image is from Feb. 12, 2012, and the right image from July 28, 2013. The new crater is about 62 feet wide. Credit: NASA/Goddard Space Flight Center/Arizona State University

The crater itself is small, measuring 61.7 feet (18.8 meters) in diameter, but its influence large; debris excavated by the sudden release of energy flew for hundreds of meters. More than 200 related changes, including surface material swept away and smaller secondary impacts, were spotted up to 19 miles (30 km) away. Before and after photos clearly show that less than a year prior, no crater was there.

Watch for the thin crescent moon to join brilliant Venus at dusk in the western sky this evening. Created with Stellarium

Watch for the thin crescent moon to join brilliant Venus at dusk in the western sky this evening. Created with Stellarium

Hundreds of changes have been recorded by the Lunar Reconnaissance Orbiter during its four years at the moon by comparing old and new images called “temporal pairs”. More than 25 new impacts have been discovered this way.

While we’re on the topic, the crescent moon will pass just 3° south or left of Venus this evening in the western sky at dusk. They should make for an attention-grabbing scene. Be sure to look up!

Unique eclipse to darken North Pole’s first day of sunshine

Eclipse March 20

The path of totality passes over far more water than land during tomorrow’s total solar eclipse.  Areas outside of totality will see a partial eclipse with varying amounts of the Sun visible depending on location. The eclipse happens during mid-morning hours across central Europe. Credit: Larry Koehn / shadowandsubstance.com

Tomorrow March 20, coincidentally the first day of spring, the moon’s shadow will sweep across the Danish Faroe Islands and darken the Norwegian archipelago Svalbard before setting at the North Pole. It’s a little unusual to have a total solar eclipse occur on an equinox, but one that ends at sunset directly at the North Pole makes it unique.

Global map showing where the eclipse will be visible along with times, which are given in UT or Universal Time. Subtract 4 hours for EDT, 5 for CDT and so on. Credit: Fred Espenak

Global map showing where the eclipse will be visible along with times, which are given in UT or Universal Time. Subtract 4 hours for EDT, 5 for CDT and so on. Click for an interactive map with times for your city. Credit: Fred Espenak

Die-hard totalitarians – utterly the wrong word for those who travel the world to see as many total solar eclipses in one lifetime as possible – are already cozied up in a hamlet in the Faroes or on a ship in the Arctic Ocean near Svalbard, where the weather forecast tomorrow is for partly sunny skies and a high of 0° F (-18° C). For a little more money, some will board a special eclipse jet and fly above the clouds directly within the eclipse path.

Animation of the March 20 total solar eclipse. The small black spot is the umbra or core of the moon's shadow. The larger gray area is the penumbra. Credit: NASA

Animation of the March 20 total solar eclipse. The small black spot is the umbra or core of the moon’s shadow. The larger gray area is the penumbra, where a partial eclipse will be visible. The longest duration of totality – 2 minutes 47 seconds – will occur off the coast of the Faroe Islands. Credit: NASA

“Umbraphile” is the real word for those who crave the moon’s shadow. Because of the distant location and lack of land to stand on, their number will be tiny compared to the millions of regular folk who’ll witness a partial eclipse across all of Europe, the northern third of the African continent, north-central Asia and the Middle East. The farther north you live, the deeper the moon will bite into the Sun.

If I could, I’d opt for the North Pole. It’s been in darkness the past six months with only the glow of twilight in recent weeks. Tomorrow, for the first time since the fall equinox, the sun will poke above the horizon. For a couple minutes during its return, the moon will cover the Sun’s face and polar skies will darken for a brief time.

The view from the north pole will be nothing short of amazing with the Sun setting in total eclipse. Source: Stellarium

The view from the North Pole will be nothing short of amazing with the Sun skimming along the horizon while briefly in total eclipse. Source: Stellarium

Now that sounds like an amazing thing to see. Imagine wintering at the North Pole, waiting 6 months for the Sun’s return, only to see it robbed (temporarily) by the moon getting in the way.

I suppose you wouldn’t complain. After all, a total solar eclipse on the first day of spring at the pole happens only once every 400,000-500,000 years!

Solar eclipses usually happen a few times a year when the new moon passes directly between the Earth and Sun, completely blocking the Sun from view for several minutes of totality. Because the moon’s shadow on Earth is rather narrow – about 125 miles wide – only those living within that strip will see a total eclipse. Far more people will witness a partial eclipse, which will be visible across thousands of miles.

During a solar eclipse, the moon gets directly between Sun and Earth and casts its shadow along a narrow band on our planet's surface. Credit: NASA

During a solar eclipse, the moon gets directly between Sun and Earth and casts its shadow along a narrow band on our planet’s surface. Credit: NASA

Would you like to see the total eclipse as it happens and not spend a cent? SLOOH’s online observatory will stream the event starting at 3:30 a.m. CDT.

Sorry, I should have told you about that little catch. The eclipse happens during morning hours across Europe. That translates to very early morning hours from the U.S. You can also watch it at the Virtual Telescope’s site beginning at 3:15 a.m. CDT.

Head to bed early if you want to see it. I hope to share eclipse photos gathered online tomorrow. The next eclipse, a total lunar, will come at the next full moon on April 4th and be widely visible across the Americas.

It’s double duo week: Moon-Jupiter and Venus-Uranus

The nearly full moon is in conjunction with Jupiter tonight. Their minimum separation of 5 happens around 10 p.m. (CST). Source: Stellarium

The nearly full moon is in conjunction with Jupiter tonight. Their minimum separation of 5° happens around 10 p.m. (CST). Source: Stellarium

I looked until around 11 p.m. last night but moonlight diluted any aurora that may have out. But the predicted storm did hit between about 2 a.m. and dawn this morning. While some readers might think I stay up all night, I really did sleep through this aurora. I know at least a few of you saw it. Tonight, there’s a chance for more minor storming.

There’s also an even better chance you’ll be struck by two very bright objects in the eastern sky at nightfall: a plump gibbous moon and the jolly giant planet Jupiter. They’ll be in conjunction tonight just ahead of Leo’s brightest star Regulus. Pairings like these make for great company and contemplation while walking the dog at night.

Venus and Uranus will be very close together on March 4th, an ideal time to find the fainter planet in binoculars. Source: Stellarium

Venus and Uranus will be very close together on March 4th, an ideal time to find the fainter planet in binoculars. Source: Stellarium

A planet-to-planet pairing occurs on Wednesday evening the 4th when Venus and Uranus will be just 1/3° apart. Like last month’s close graze with the crescent moon, this will provide yet another easy opportunity to see a planet that is too dim for most to see with the naked eye. Just point your binoculars at brilliant Venus in late twilight in the western sky and look for a tiny speck of light immediately below it.

I love how planets can appear so close and yet be so far from one another. Venus is a quick jaunt at 128 million miles from Earth compared to Uranus’ 1.9 billion miles, nearly 15 times farther away.

The stars in the constellation of Orion all look like they are at the same distance. Turn the constellation through 90 degrees and you can see the stars are actually at different distances. Two of the Belt stars plus the two bottom stars in the constellation are far from the sun but relatively near one another in space. Betelgeuse is much closer to us. Credit: ESA

The stars of Orion might be easily dismissed as all being at the same distance from us. That’s how they appear on the 2-D “surface” of the sky. Butturn the constellation through 90 degrees (look at it from the side) and you can see the true distances of each star. Notice that Betelgeuse is much closer to us than the Belt stars. Credit: ESA

When we see conjunctions and appreciate the real distances between objects in the sky, it’s helpful to remember the same applies to the constellations. We see familiar rectangular outline of Orion and the neat arrangement of his three belt stars by lucky chance. Looking back toward Orion’s stars from a different direction in space (a couple hundred light years beyond the solar system) Orion would be unrecognizable.

Watch Io snuff out Ganymede at Jupiter tonight

The moon kisses up to Aldebaran last night (Feb. 25) during evening twilight seen from Duluth, Minn. Credit: Clint Austin

The moon kisses up to Aldebaran last night (Feb. 25) during evening twilight seen from Duluth, Minn. Credit: Clint Austin

First, my apologies. I so wanted to alert you to the half moon’s pass of the bright star Aldebaran last night. But there were network problems with the blog, and I wasn’t able to post.

No doubt many of you noticed it all the same. A quick look up at the moon and you couldn’t help but see the star a little more than one lunar diameter to the southwest. The farther north you lived, the closer they drew together. In far northeastern Canada the moon occulted Aldebaran. Checking the moon several times overnight, it was amazing to see how quickly it departed Aldebaran, forced by its perpetual orbital motion to “go east, young moon, go east”.

Tonight our satellite moves a fist further east in Taurus the Bull and beams atop Orion the mighty hunter at nightfall. It’s 8 days past new phase and absolutely resplendent with craters. Sic your telescope on it and marvel at the ruggedness of all that ancient terrain bludgeoned by forgotten meteorites and asteroids.

The view through the telescope this evening just before Ganymede is eclipsed by Io's shadow. Created with Stellarium

The view through the telescope this evening just before Ganymede is eclipsed by Io’s shadow. The deepest part of the eclipse will occur around 9:35 p.m. Created with Stellarium

East of Orion you’ll find the blazingly bright planet Jupiter right along the border of Leo and Cancer. I’ve written before about this being a special season for Jupiter’s moons. Because Earth’s equator is aligned with Jupiter’s, and the brightest moons orbit above the planet’s equator, we can see them eclipse and occult one another in what astronomers call “mutual events”.

Tonight, little Io will cast its shadow on the largest Jovian moon, Ganymede. While not a total eclipse, it’s close, with a good deal of Ganymede in shadow at maximum (although not 97% as I wrote earlier). This should be easily visible in a small telescope at low to medium magnification. The eclipse begins at 9:31 p.m. CST (3:31 UT) and ends at 9:40 p.m. (3:40 UT). Jupiter will be very well placed for viewing across all of the Americas at the time.

Now here's something cool - a double mutual event. Europa eclipses then occults Io on January 28 captured by Theo Ramakers of Oxford, Georgia.

In this double mutual event, Europa eclipses then occults Io on January 28 captured by Theo Ramakers of Oxford, Georgia. The eclipse is quick in the time lapse, occurring about 1/2 second in. Look for the shadow passing across the top of Io.

Get that scope out at least a half hour beforehand and let it cool down if you’re in a cold climate otherwise Jupiter will look all mushy. Then start watching about five minutes before the eclipse begins, so you can get familiar with Ganymede’s normal brightness.

During the eclipse you won’t be able to see Io’s shadow with your eye, but Ganymede will fade by one magnitude and then re-brighten as the shadow first covers and then departs its 3,275-mile-wide globe.

Wishing you clear or at least partly cloudy skies tonight!

Planetary traffic jam lookback / Speedy comet update

To capture the planet Uranus (at lower right) I had to overexpose the bright, sunlight lunar crescent. Naturally, this made the earth-lit portion stand out very clearly. Credit: Bob King

To capture the planet Uranus (at lower right) I had to overexpose the bright, sunlight lunar crescent. Naturally, this made the earth-lit portion stand out very clearly. Credit: Bob King

Wow, we had quite a weekend. The moon visited every evening sky planet while Venus and Mars squeezed together for their closest approach of the year. We’ve already looked at the “triple play” conjunction that occurred Friday. I thought it would be fun to look at the other alignments that have made the past few nights so memorable.

The moon (top) along with Venus and Mars Saturday evening Feb. 21, 2015. Credit: Guy Sander

The moon (top) along with Venus and Mars Saturday evening Feb. 21, 2015 from near Duluth, Minn. Credit: Guy Sander

Here, Guy has enlarged portions of the image to better see all three planets involved. Credit: Guy Sander

Here, Guy has enlarged portions of the image to better see all three planets involved. Credit: Guy Sander

Venus and Mars were still close Sunday night Feb. 22, but they will part in the coming days as Venus moves up and Mars slides closer to the Sun. Credit: Bob King

Venus and Mars were still close Sunday night Feb. 22, but they will part in the coming days as Venus moves up and away from the Sun while Mars slides closer. Credit: Bob King

As for that fast-moving comet discovered last week and en route to the evening sky, Karl Battams, an astrophysicist and computational scientist based at the Naval Research Laboratory (NRL) in Washington DC, is right now at his computer measuring positions of the comet from photos made with the orbiting Solar and Heliospheric Observatory (SOHO).

Comet SOHO-2875 survived its close passage of the Sun and may make an appearance in the evening sky soon. This photo montage was made using the coronagraph (Sun-blocking device) on SOHO. Click to watch a movie of the comet. Credit: NASA/ESA

Comet SOHO-2875 survived its close passage of the Sun and may make an appearance in the evening sky soon. This photo montage was made using the coronagraph (Sun-blocking device) on SOHO. Click to watch a movie of the comet. Credit: NASA/ESA

Once enough positions are known, he’ll send the data off to the Minor Planet Center where a preliminary orbit will be determined. With that information I can make a nice map showing us where to look for it. Stay tuned.

Moon meets Uranus next / Oddball comet update

Wow! What a fine photo from last night's conjunction. Venus, Mars and waxing crescent Moon over sculpture "Calling The Power" by Larry Bechtel at Vic Thomas Park. Credit: Terry Aldhizer

Wow! What a fine photo from last night’s conjunction. Venus, Mars and the waxing crescent Moon over the sculpture “Calling The Power” by Larry Bechtel at Vic Thomas Park in Roanoke, Virginia. Credit: Terry Aldhizer

Close-up of the moon, Venus, Mars gathering last night. The earthshine on the moon is amazing! Credit: Terry Aldhizer

Close-up of the moon, Venus, Mars gathering last night. The earthshine on the moon is amazing! Credit: Terry Aldhizer

We were  hopelessly cloudy for last night’s conjunction. You were luckier I hope. Don’t forget, tonight’s thicker crescent passes very close to the planet Uranus, occulting it from the far northeastern U.S. and southeastern Canada. Venus and Mars will also be in conjunction today and a smidge closer that they were yesterday evening.

Wide view of Uranus and the moon on tonight (Feb. 21)  as seen from the Midwest about an hour and a quarter after sunset. Source: Stellarium

For the Central Time Zone, Uranus will lie 0.5° west of the moon in twilight, 1° away the Mountain States and 1.5° for the West Coast. What a great opportunity to spot the 7th planet in binoculars. Not only that, but a simple time exposure with a tripod-mounted camera will easily show it. Wait till late twilight and try a range of exposures starting around 5 seconds at ISO 800 with the lens wide open to f/2.8 or 3.5.

Uranus in early twilight (left) just before its dramatic disappearance behind the earth-lit edge of the moon tonight Feb. 21 as seen from Portland, Maine. 36 minutes later Uranus emerges at the bright crescent’s edge. Both disappearance and reappearance occur in a dark enough sky to see in a small telescope. Source: Stellarium

Map showing where the occultation of Uranus by the moon will be visible. Between the white lines, it’ll be visible in a dark sky. Blue is twilight and the red dotted line is daytime. Uranus is too faint to see in the daytime sky. Click the map to get a list of disappearance and reappearance times for a variety of cities. Credit: IOTA/Occult

Most of the time the moon occults stars along its path since there are a lot more of those than planets. Because they’re so remote, stars are little more than points of light; as the moon moves over them they disappear with surprisingly suddenness. Since Uranus displays a real, measurable disk it will take a second or two to disappear behind the moon’s edge.

SOHO-8275 comet about 7 east of the Sun this morning at 9:06 a.m. (CST) this morning. Credit: NASA/ESA

SOHO-2875 comet about 7 east of the Sun this morning at 9:06 a.m. (CST) this morning. Credit: NASA/ESA

The little comet we discussed yesterday continues trekking away from the Sun after its searing encounter two days ago. SOHO-2875 still shows a short tail and hangs in there around magnitude +3.5. It reached the edge of the field of view of the Solar and Heliospheric Observatory’s C3 wide-field coronagraph this morning headed east-northeast.

Since the field of view of the coronagraph is 15°, the comet’s presently about 7° east of the Sun, too close to spot yet in twilight. Give it 4-5 more days and someone may see it in a telescope in evening twilight. As soon as an orbit becomes available I’ll put together a chart to help you find it.