Fire haze turns sun into big red ball

A towering cumulus cloud partially eclipses the setting sun Monday evening seen from Duluth. Haze from Canadian forest fires has returned to the region making for deep red suns around sunrise and sunset. Credit: Bob King

Smoke from fires in the Canada’s Northwest Territories continues to funnel down across Manitoba and into the U.S. Upper Midwest creating an artificial overcast of smoky haze. We’ve lost the blue clarity of our daytime sky; at night stars look much dimmer seem more distant.

If you’re a skywatcher, everything in the nighttime sky looks noticeably fainter, especially objects within 20° of the horizon. I feel as if I’m looking through gauze. The unusually pallid appearance of the sky from dinnertime onward might make you think the sun has already set until you realize it’s still out there in the west looking little brighter than the full moon.

Funny. Yesterday, when I took this picture, someone pulled up alongside my car and remarked at how amazing the moon looked. The strangely faint sun had thrown him off!

The full sun shortly before setting yesterday July 28, 2014. You might see three small sunspot groups – two to the right of center and a third a short distance within the sun’s left limb. Credit: Bob King

Fire smoke generally scatters away nearly all light from the setting sun except deep oranges and reds.

The haze is both good and bad when it comes to observing. We like a big red sun, but it’s tough sacrificing otherwise clear nights.

I shouldn’t complain. People farther north, where the smoke is heavier, have to breath it.

Keep watch on the moon the next few nights as it waxes from crescent to half. If you live where there’s forest fire smoke, chances are you’re in for some red moons too.

Sunrise and sunset – nature’s most beautiful illusions

Earth turns on its axis to greet the sun at sunrise each morning of the year. Credit: Bob King

Every day the sun rises, crosses the sky and sets. And it does it again and again and again like the perpetually repeating cycle of events in the movie Groundhog Day.

Except perhaps for a few remaining Flat-Earthers, we know what’s going on here. The sun’s not doing the moving. Instead, the Earth’s rotation causes the apparent motion of the sun across the sky. Yet the sense of the sun’s movement is so powerfully ingrained in our experience you might balk if I told you it’s essentially sitting still in the sky.

Every day the turning Earth causes the nearly static sun to rise in the east at sunrise and set in the west at sunset. Credit: Canadian Space Agency

For you to see a sunrise, Earth must rotate on its axis until your location faces the sun as it crests above the planet’s curvature. The following morning, when Earth rolls around after another 24 hours, the sun is very nearly in the same place in the celestial sphere as the previous morning. Once again, we see the sun ‘rise’. Ditto for the next morning and the next. It’s like turning over in your bed each and every morning and seeing your spouse in the same spot. Or very nearly.

If the Earth spun but stood in one spot never circling the sun, we would meet the rising sun at precisely the same time and place every day ad infinitum – a true Groundhog Day scenario. But the Earth orbits or revolves around the sun as surely as it rotates. Just like our daily spin, our planet’s revolution is reflected in the sun, which appears to slowly crawl across the sky, inching its way from one background zodiac constellation to the next, during the course of a year.

The orbiting and titled Earth cause slow but continuous changes in the times of sunrise and sunset during the course of a year. Credit: Thomas G. Andrews, NOAA Paleoclimatology

The ever-changing times of sunrise and sunset stem from the Earth’s orbital travels combined with the shifting seasonal tilt of the planet. From December 21 until June 21, as the amount of daylight increases in the northern hemisphere, the sun appears to travel slowly northward in the sky and we meet its welcome rays a couple minutes earlier each morning.

The sun’s yearly motion across the sky during the year traces out a path called the ecliptic. The top of the curve, at right, is the sun’s position during the summer. The low part of the curve is the sun’s location during winter. The up-and-down path is a reflection of the 23 1/2-degree tilt of the Earth’s axis. Illustration and animation by Dr. John Lucey, Durham University

Then from June 22 to December 20, Earth’s orbital motion causes the north polar axis to slowly point away from the sun. The sun appears to slide south as the hours of daylight wane, and we meet the sunrise a minute or two later each morning.

The sun, located some 26,000 light years from the center of the Milky Way galaxy, takes about 220 million years to make one revolution around its core moving at 483,000 mph. Credit: ESO

Earth moves along its orbit at an average speed of 67,000 mph (108,000 km/hr).

How about the sun? If I left the impression that it’s totally static I apologize. Yesiree, it’s moving too – at the astonishing speed of 483,000 miles per hour (792,000 km/hr) around the center of the galaxy.

Don’t look now, but you and I are going on the ride of our lives.The only reason stars remain static in the sky over the span of many generations despite the sun’s hurry is because nearly all of them are too far away to show a shift in position with the human eye. Telescopes, which magnify everything including motion, do show very subtle changes in the positions of nearby stars over much shorter time intervals.

Rising each morning to the same old sun, I try to remind myself that with every rotation comes a new opportunity to spin some joy into the day.

Tomorrow’s new moon foretells October’s solar eclipse

Tomorrow July 26, 2014, the invisible new moon will pass a few degrees south of the sun in the daytime sky. Stellarium

New moons aren’t much to look at. You can’t even see them most months of the year. That’s true for tomorrow’s new moon which will invisibly accompany the sun in its journey across the sky.

New moons occur about once a month when the moon passes between the sun and Earth. We can’t see them for two reasons: first, no sunshine touches the Earth-facing side when the moon lies in the same direction as the sun. It’s completely dark. From our perspective, the out-of-view lunar farside gets all the sunlight. Second, since the moon is nearly in line with the sun, it’s utterly lost in the glare of daylight.

The moon seesaws 5 degrees north and south of Earth’s orbit during its monthly cycle because its orbit is tilted with respect to Earth’s. Only when the moon crosses the plane of Earth’s orbit at the same time as a new moon do we see a solar eclipse. Illustration: Bob King

We normally have to wait two days after new moon – when the moon’s orbital motion carries it to the left (east) of the sun – to see it as a thin crescent at dusk.

Most of the time the moon passes north or south of the sun at new phase because its orbit is tilted 5 degrees with respect to Earth’s. But 2.4 times a year on average, new moon coincides with the time the moon’s seesawing path slices through the plane of Earth’s orbit. For a brief time during that crossing, all three bodies are aligned and happy earthlings witness a solar eclipse.

If the alignment is imprecise, the moon blocks only a part of the sun, giving us a partial solar eclipse.  If dead-on, we see a rarer total solar eclipse.

View of the partial solar eclipse across the Upper Midwest a half hour before sunset on October 23. By coincidence, Venus will be near conjunction at the same time and only a couple moon diameters north of the pair. Seeing the planet in a telescope will still be challenging because of daylight glare.  Stellarium

On October 23 this year, the lineup at new moon will be a good if imperfect one with a maximum of 81% of the sun covered. The partial eclipse will be visible across much of North America; from the eastern half of the U.S. and Canada the event will occur near sunset, adding a touch of drama to the scene.

I wrote earlier that we can’t see a new moon. That’s only partly true. We mostly pay attention to the sun’s changing shape during solar eclipses, but the dark, curving bite working its way slowly across the sun’s disk is none other than the new moon seen in silhouette.

Shhh! Don’t wake the sun

Contrast these views of the nearly spotless sun on July 16-17, 2014 with a picture taken about two weeks earlier (below). Credit: Giorgio Rizzarelli

Who doesn’t enjoy a nap on a lazy summer afternoon? That’s what the sun’s been up to past few days. Instead of a steady parade of sunspots, it put its pencils away and went to sleep. For a time on July 17 not a singe magnetic blemish marred the entire Earth-facing hemisphere. The last time that happened was nearly 3 years ago on Aug. 14, 2011.

Ten groups including three visible with the naked eye dot the sun on July 8, 2014. Credit: NASA

The solar blank stare lasted but a day; by the 18th two small groups emerged. Today three little spot clusters have emerged but again, they’re on the small side.

I think the reason the sun looks so stark is that only two weeks ago nearly a dozen sunspot regions freckled the disk including three visible with the naked eye with a safe solar filter.

These ups and downs aren’t unusual unless this downturn continues for weeks. Expect more bubbles of magnetic energy to rise from beneath the glaring surface of the sun called the photosphere and spawn fresh groups soon. Because we now have eyes on the farside of the sun courtesy of the dual STEREO solar probes, we know the complete story. There are at least seven spotted regions in hiding there today.

Sunspot numbers are plotted for the last three solar cycles through the present. The double peak of the current cycle is shown. Credit: NASA

Sunspots and flares peak approximately every 11 years. We’re still riding the roller coaster near the top of the arc after the most recent solar maximum in late 2013. Some maxima are strong, others weak. The current max – Cycle 24 – is the weakest since Cycle 14 in February of 1906 and one of the wimpiest on record. Occasionally a cycle will have two peaks like the current one. The first peak occurred in Feb. 2012 and the second just this past June. What makes Cycle 24 even more unusual is that the second peak is higher than the first – the first time this has ever been recorded. Like people, every maximum has a personality of its own.

Doug Bieseker of the NOAA Space Weather Prediction Center has analyzed historical records of solar activity and he finds that most large events such as strong flares and significant geomagnetic storms typically occur in the declining phase of solar cycles—even weak ones, so don’t give up hope for some great auroral displays ahead.

A coronal mass ejection blew off on the farside of the sun early this morning July 20. It appears to envelop Jupiter, but the planet is 490 million miles in the background. SOHO uses an occulting disk to block the brilliant sun. Credit: NASA/ESA

The sun’s got a buddy this week – Jupiter! We can’t see the planet from the ground because it’s swamped by solar glare, but the Solar and Heliospheric Observatory (SOHO) has a great view from space. Watch the sun approach from the right and pass the planet over the next few days. After the 24th, Jupiter will move into the morning sky.

Huge sunspots scar the sun this week

Ten groups including three visible with the naked eye protected with a safe filter dot the sun today. Photo by the Solar Dynamics Observatory (SDO) taken at 8 a.m. CDT today July 9. Credit: NASA

A trio of impressive sunspot groups are parading across the sun’s face this week. Regions 2108, 2109 and 2110 are all closely-spaced and near the center of the disk today. All three require nothing more than a pair of eyes and a safe solar filter to view.

The sun seen through a standard 200mm telephoto lens and solar filter this morning gives you an idea of how the big sunspot groups look to the naked eye. Credit: Bob King

I took a look through my handy #14 welders glass this morning and saw 2110 distinctly; the other two groups blended into a single ‘spot’ at first. Looking closely I could barely split them into two separate dots. The view was spectacular at 30x in my little telescope with a total of ten sunspot groups and lots of fine detail in the three biggest.

Given high sunspot counts, the chance for flaring has been increasing in recent days. Today there’s a 75% chance for moderately strong M-class flares and 20% chance for the most powerful X-class variety.

Safe solar filters come in several varieties of optical / coated plastic and glass. Click to see ones you can purchase from Rainbow Symphony. Credit: Bob King

Curiously, none of the three biggies has shot off a large flare in the past day or two; they’re all currently stable. But the inconspicuous group 2113 fired off a beefy M6 flare only yesterday. It’s not expected to affect Earth, but because 2113 hides a complex magnetic field, future M-class or stronger blasts may be possible.

M6-class solar flare eruption from sunspot group 2113 captured July 8, 2014 at 11:24 a.m. by SDO. Credit: NASA

It seems like we’re due for aurora, so I’d be surprised if the current activity doesn’t lead to at least a minor storm soon. I’ll keep you updated.

Farewell Jupiter, hello moon!

The 2-day-old lunar crescent will shine low in the west-northwest tonight June 29, 2014. This view shows the moon about 30 minutes after sunset. Not far away – hidden by the tree – Jupiter makes its last stand. See below. Source: Stellarium

Tonight’s returning crescent moon will help us bid adieu to a planet that brought us through winter and spring to the doorstep of summer.

Jupiter’s put on a great show in Gemini this year. We’ve watched the nightly ballet of its four bright moons, pondered the shrinking of the Great Red Spot (how small it will get nobody knows) and witnessed the planet in many fine conjunctions with the crescent, quarter, gibbous and full moons.

That’s a lot of visual delight, but being one of the brightest planets, Jupiter rarely fails to please. Tonight you might see it for the last time this season using the moon as your guide. Face west-northwest about a half-hour after sunset. With binoculars, sweep the sky about 12 degrees to the right and below the crescent moon. Can you see it with your naked eye?

With a clear view to the west-northwest tonight, the moon will help you find Jupiter one last time. The map shows the sky 30 minutes after sunset from the central U.S. Jupiter lies about 12 degrees – a little more than a horizontally-held fist at arm’s length – to the right and below the moon. Use binoculars first and then see if you can spot it without optical aid. Source: Stellarium

No planet escapes the glare of the sun. The apparent movement of the sun across the sky caused by Earth’s revolution around it means that sooner or later our driven star catches up with the slower-orbiting planets that lie beyond the Earth. Indeed, the sun’s been gaining ground on Jupiter ever since January 5. On that date, the planet was at opposition, rising at sunset and remaining visible until the next morning’s sunrise. The very next day the sun gained 4 minutes on it and hasn’t stopped since.

Jupiter’s now (almost) hopelessly lost in bright evening twilight. It will still roast in the BBQ glow of the sunset until July 24 when it passes just a fraction of a degree north of the sun in conjunction. For several days before and after that date we’ll get to see it in SOHO’s coronagraph, an instrument that blocks out the sun to reveal the solar corona, background stars and occasional comet and planet crossings.

Wow! On Aug. 18, days after Jupiter returns to view in the morning sky, it will pass only 0.2 degrees (1/3 the diameter of the full moon) from Venus in the constellation Cancer. Source: Stellarium

As the sun passes and leaves Jupiter behind, the planet re-emerges in the east in morning twilight in early August. And what a grand entry it will be! On August 18 Jupiter passes just 0.2 degrees from Venus in one of the year’s most spectacular conjunctions.

If you recall, Jupiter spent most of this year in the constellation Gemini beneath the bright ‘twin stars’ Castor and Pollux. On its return in August you’ll be struck by how far the planet has moved east along the zodiac. Ceaselessly orbiting the sun, Jupiter will have abandoned Gemini for the faint constellation Cancer the Crab. And so it goes, round and round and round.

Chance for auroras tonight June 21-22 / Comet Jacques approaches the sun

A large cloud of hydrogen gas called a filament erupts from the sun on June 19, 2014. We normally see these fiery gas clouds along the sun’s limb as pink flames. Here it shows in silhouette.

Welcome to the first day of summer! The new season’s first night may just bring us a blush of northern lights. A filament – another name a solar prominence except seen in silhouette against the sun’s bright disk – erupted from the sun’s southern hemisphere Thursday. Flung into space because of some magnetic disturbance, most of the material shot off to the northeast, but some was Earth-directed. It should arrive overnight and possibly set off a minor aurora storm.

A portion of a CME / filament eruption Thursday may spark auroras tonight and tomorrow night. This photo was  made with the coronagraph on the Solar and Heliospheric Observatory. Credit: NASA/ESA

NOAA forecasters are calling for a 25% chance of a minor storm for mid-northern latitudes tonight and a 20% chance Sunday night.

The picture above showing the coronal mass ejection was taken with the Solar and Heliospheric Observatory’s coronagraph, a special camera with an occulting disk that blocks direct sunlight so astronomers can see what’s going on around the sun. Photos taken today with the instrument show a new visitor – Comet Jacques. You can watch it enter the field of view at lower left.

There are faint hints of a tail in these 24 consecutive images compiled into an animation by Rob Kaufman.

Amateur astronomer Rob Kaufman compiled multiple still photos into a video showing the ‘blip’ on the move. It’s currently around magnitude 7, but once it passes the sun and moves into the morning sky next month, it may be bright enough to spot in binoculars. More on that as the time approaches.

Another erupting filament photographed late Friday night June 20 with NASA’s Solar Dynamics telescope.

Boom! Boom! Boom! A solar flare triple crown

Three X-class flares erupted in sunspot group 2087 over a 24-hour period on June 10-11, 2014. A portion of the coronal mass ejections from the eruptions may brush the Earth in the next few days. Credit: NASA

Move over California Chrome.  After delivering three X-class flares in two days, sunspot group 2087 wins the triple crown for solar eruptions. And the fun’s not over yet.

The large, complex sunspot region 2087, pictured today June 12 at 8:30 a.m CDT, kicked off three powerful X-class flares on June 10 and 11. More flares are expected from the group in the coming days as it turns toward the Earth. Credit: NASA

Between it and two other spotted regions (2080, 2085) there’s a 60% chance for moderate M-class flares and 30% chance for more X-flares through Saturday. Plus, it turns out that part of the blast from 2087′s double-X flare is whooshing its way toward Earth right now.

Look at all the sunspots! Skywatchers with safe solar filters have a bounty of observing opportunities this week. Catch the big groups 2080 and 2085 (far right) before they rotate over to the sun’s other side. Credit: NASA

Most of the solar plasma blasted sideways off the sun after the eruptions but not all. NOAA space weather forecasters now predict a 20-25% chance of minor auroral storming overnight tonight through Saturday. With each day that passes, region 2087 inches closes to the center of the sun, where it will face Earth more directly, improving the outlook for auroras in the wake of new flares.

New sunspot group enters the stage with guns a-blazing

If ever an “X marked the spot”, this ‘x’ is it. It’s the first of a pair of x-ray flares that popped this morning at 6:42 a.m. CDT in sunspot region 2087. Photo taken in extreme ultraviolet light by NASA’s Solar Dynamics Observatory. Credit: NASA

Sunspot region 2087 announced its arrival on the sun’s southeastern limb today with a real show of firepower. Like a double-barreled shotgun, the group blasted off an X2.2 flare at 6:42 a.m. CDT followed 70 minutes later by an X1.5 at 7:52.

The second flare, an X1.5, peaked around 7:57 a.m. CDT today June 10. Credit: NASA

Although neither was directly in line with Earth, ultraviolet light from the explosions caused a wave of ionization in our planet’s upper atmosphere that affected radio propagation over Europe. Images from NASA’s STEREO solar spacecraft show a coronal mass ejection moving off to one side of the side. It’s not expected to affect the Earth.

The lively sunspot group 2087 has just rotated around the southeastern limb of the sun. 2080 and 2085 are both magnetically complex groups that could spawn M-class flares of their own. Photo taken this afternoon at 1:15 p.m. CDT. Credit: NASA / SDO

Interestingly, the ACE spacecraft, which measures changes in the direction of the magnetic field bundled with the solar wind, dipped south right around the time of the flares. While the two events may be unrelated, anytime the field tilts south, conditions are opportune for the sun’s particle wind to hook into Earth’s magnetic field and possibly fire up auroras.

A large coronal mass ejection, sparked by the double-flare photographed at 9:39 a.m. today by NASA’s STEREO-B spacecraft, expands away from the sun. Credit: NASA

Though it may not be related, the magnetic direction of the wind has been rapidly shifting from north and south all morning and afternoon. Solar astronomers had expected to see flares from sunspot regions 2080 and 2085. Both have complicated delta class magnetic fields ripe with the potential for sparking solar storms. Both also squarely face the Earth. Should an X-class flare erupt in either, the material ejected could wind up producing a geomagnetic storm and accompanying northern lights later this week. So far, they’ve been ‘quiet’ today.

There’s also a chance the plasma cloud released by the X-flare blasts could strike a glancing blow to Earth’s magnetic field; the new group may also continue to produce flares as it rotates into a favorable, Earth-facing position on the sun’s disk.

Surprise aurora puts on Sunday morning show

Sallie Carlson of Lutsen, Minn. took this photo this morning June 8, 2014. She reported aurora visible overhead and rays bright enough to overtake the light of the gibbous moon. Copyright: Sallie Carlson

Ouch! Missed a great aurora this morning. The potential was there late yesterday afternoon when the magnetic field bundled with the solar wind tilted south and hooked into Earth’s magnetic domain. Activity increased but nothing was visible here in Duluth up till midnight. Moonlight may have washed out any early, low aurora present.

That all changed sometime around 1 a.m. right about the time I entered dreamland. Others who stayed up late reported lots of red rays visible even from moderately light-polluted locations:

“1:45 am. slight calm after 45 mins of intense displays with lots of red showing even in my semi-urban location,” said reader Paul Contant of Penticton, British Columbia, Canada.

Bar chart showing the jump in the Kp index overnight. A southward tip in the interplanetary magnetic field (which originates on the sun) and increase in the speed of the solar wind were responsible for the display. Activity is ramping down this morning but there’s still a chance for auroras tonight. Credit: NOAA

Auroras were seen all the way to the zenith throughout the morning hours as the Kp index, an indicator of magnetic activity high overhead, surged to ’6′ spawning a G2 moderate magnetic storm.

An all-sky aurora with green and purple curtains early starting up about 1:30 CDT and going until dawn as seen from southern Alberta, Canada. The Big Dipper is above the Barn. The purple color is from blue scattered sunlight hitting the red tops of the auroral curtains. Details: 16-35mm lens at f/3.2, 20 seconds at ISO 1600. Copyright: Alan Dyer

This morning’s aurora was a complete surprise. Mostly quiet conditions were expected and still are. NOAA’s space weather center calls for only a small chance for auroras tonight but you better believe I’ll be on the lookout. Let us know if you see anything, too.