See the starry stepping stones of spring

Like stepping stones across the twilit sky, Sirius, Orion's Belt, the Hyades and Pleiades star clusters (and Venus too!)  follow one another across the western sky during at nightfall in April. Credit: Bob King

Sirius, Orion’s Belt, the Hyades and Pleiades star clusters (and Venus too!) splay across the western sky at nightfall in April. Photo taken April 4, 2015 around 8:45 p.m. local time. Credit: Bob King

They may all officially belong to the winter sky, but Sirius, Orion’s Belt, the Hyades and Pleiades tilt over in the most appealing way every April. With Venus joining the scene, you can star hop from one to the next the way you might use stepping stones to cross a stream. Take a look in the west during evening twilight, and you’ll see what I mean.

Each “stone” is distinctive in its own right — Sirius (the brightest star in the sky); Orion’s Belt (a stand-out star pattern visible across the globe); the Hyades (bright star cluster and the closest one to Earth at just 153 light years); the Pleiades (the famed Seven Sisters star cluster shaped like a dipper) and Venus, brightest planet in the sky.

Two fists held at arm’s length separate Sirius from Orion’s Belt and Orion’s Belt from the Hyades. You can squeeze one fist between the Hyades and Pleiades and the Pleiades and Venus. There’s a rhythm or spacing to the pattern pleasing to the eye.

Watch for Venus and the Seven Sisters to draw closer and closer this week. From April 10-12 (Friday-Sunday), they’ll be just 2.5° apart and a wonderful sight together in binoculars.

There’s also a hidden pattern among the five objects relating to their distances. At 8.6 light years, Sirius is the 5th closest star system beyond the Sun. Orion’s Belt stars all lie much farther – between 800 and 1,000 light years away. With the Hyades, our gaze returns to the “neighborhood” 153 light years from Earth, recedes again to 444 light years with the Pleiades and returns to our own front yard with Venus, a mere 110 million miles from home.

Near-far-near-far-near. E-I-E-I-O! Anyone for a round of Old MacDonald Had a Farm?

Typhoon Maysak strengthened into a super typhoon on March 31, reaching Category 5 hurricane status on the Saffir-Simpson Wind Scale. ESA Astronaut Samantha Cristoforetti captured this image while flying over the weather system on board the International Space Station. Credit: NASA

Typhoon Maysak strengthened into a super typhoon on March 31, reaching Category 5 hurricane status. ESA Astronaut Samantha Cristoforetti captured this image while flying over the weather system on board the International Space Station. Credit: NASA

While you’re out enjoying spring’s many rhythms, watch for the International Space Station (ISS). It’s making passes again over the U.S. and other countries during convenient evening viewing hours through late April. When brightest, the space station bests the planet Jupiter as it travels steadily (and unblinkingly) from west to east across the sky.

You can get viewing times and more information at Heavens Above (click on the ISS link), key in your zip code at Spaceweather’s Satellite Flybys page, have NASA alert you via e-mail or text message or download an app for your phone.

For the Duluth, northern Minnesota and northern Wisconsin region, here are a few viewing times:

* Tonight April 5 from 8:40-45 p.m. you’ll see the ISS track across the southern sky
* Monday April 6 from 9:22-27 p.m. a brilliant high pass straight across the top of the sky
* Tuesday April 7 from 8:29-35 p.m. high in the south. Another brilliant pass.

7 fun things to do while waiting for the world to end

Mayan 7-day weather forecast for the current week

First, brew a cup of tea or coffee, sit back at the computer and spend a few minutes at the website for edification and entertainment. The site’s creators have tried to address every cooked-up doomsday scenario out there.

Second, why not use the time to finish wrapping those Christmas presents? I usually wait till the last minute and do a schlock job folding and taping. Don’t let this happen to you. And if you’re looking for a last-minute gift, give your worried friend the hope of another tomorrow with a 2013 calendar.

Photo: Bob King

Third, take a really long walk or engage in some other form of exercise. Do this in advance of all the overeating that’s inevitable around Christmastime and you might break even.

Fourth, if you do plan a walk and your sky is clear, do so under the light of the quarter moon. Tonight it’s high in the south in the constellation Pisces and sure to provide good light for shadows. If it’s snowy where you live, the moonlight will be even more intense.

Orion’s Belt is filled with stellar riches. Photo: Bob King

Fifth, look at Orion’s Belt in a pair of binoculars. I know you’ve seen this stellar trio dozens of times, but the region surrounding them is saturated with stars just below the naked eye limit.

Point your binoculars that way for an awesome view before the moon gets too bright. Several nights ago under a very dark sky, I  could see the bling with my naked eye, palpitating at the limit of vision.

Comet C/2012 K5 (LINEAR) on Dec. 15 from Austria taken with an 8-inch scope. Smaller scopes will show a faint fuzzy streak, while 8-inch and larger instruments will give fine views of the tail. Detailed finder map below. Credit: Michael Jaeger

Sixth, if you own a telescope 6-inches or larger, a beautiful comet is passing atop the Bowl of the Big Dipper this week. Comet C/2012 K5 LINEAR shines at around 9th magnitude with a teeny-tiny head and a streamlined tail pointing northwest. I saw it in my scope the night of the Geminid shower. Absolutely beautiful. The larger your telescope, the better the view.

Seventh, call your mom or dad or someone in your family you haven’t talked to in a while and get back in touch.

Comet K5 LINEAR flies skirts the Big Dipper Bowl the next few nights. I’ve marked the comet’s position every 12 hours at 6 a.m. and 6 p.m. CST. The morning hours from 5-6 a.m. are best because the sky is moonless and comet high in the northern sky. Right-click image, save and print out a copy to use at the telescope. Stars to mag. 9.2. Created with Chris Marriott’s SkyMap software

Venus now at its best plus how to find an ancient constellation

Because Venus orbits inside Earth's orbit, we see it pass through phases like the moon as the planet revolves around the sun in 225 days. When it's nearly between Earth and sun, Venus is a crescent. When it's farthest off to the side as it is today, it appears half illuminated. Illustration: Bob King

Venus reaches greatest elongation from the sun today. That means we see it at its maximum distance from the sun in the sky, some 47 degrees. This is equal to nearly five fists held at arm’s length. Anyone who’s gone out at dawn can attest Venus rises well before the sun and blazes like white fire in the black sky. Here in Duluth, today’s maximum separation means the planet rises at 4:08 a.m. or 3 3/4 hours before the sun.

Venus at dawn. The planet reaches greatest western elongation (maximum distance west of the sun) today.

Venus goes through phases just like the more familiar moon. That’s because it’s an inner planet. During the course of Venus’ orbit around the sun, we see the planet move from one side of its orbit (where it is today) to the farside, over to the other side and then between us and the sun. The changing geometry of the Venus-sun-Earth trio causes the degree of illumination or phase to vary during that time.

Venus looks like a half moon this week as seen in a small telescope.

Notice that Venus can never appear behind the Earth like the outer planets. Because planets like Mars and Jupiter orbit behind and beyond Earth, they occasionally appear directly opposite the sun in the sky, rising at sunset and shining due south in the midnight sky. Venus is on a leash that never exceeds 47 degrees, so it never gets far enough away from the sun to shine in the sky at midnight. Mercury, being closer to the sun, is on an even shorter leash – just 28 degrees or three fists held at arm’s length. Since both planets never stray too far from the sun, they’re most easily visible during morning and evening twilight.

Orion's Belt is the jumping off point for finding the zodiac constellation Taurus the Bull. A line through the Belt upward takes you to Aldebaran. It and the Hyades star cluster form the bull's face. The two horns extend to the left, while the Pleiades cluster marks his shoulder. This map shows the sky around 7 p.m.

Our local forecast is for clear skies and subzero temperatures tonight. If you’re willing to brave the cold after dinner, step outside around 7 o’clock and look toward the southeast. You’ll see the famous three stars of Orion’s Belt a comfortable distance above the horizon.

The mythological figure of the Bull will help you visualize the constellation as the ancients saw it.

Shoot a line upward through the Belt until you smack into the next bright star. That’s Aldebaran (al-DEB-ah-ron), the brightest star in Taurus the Bull and distinctive for its orange-red color. A small group of dimmer stars in the shape of the letter V spread out to the right of Aldebaran and form the face of the Bull. These little stars belong to a star cluster called the Hyades. Look above and to the right of the Hyades to find the most famous star cluster of all – the Pleiades or Seven Sisters. How convenient that two of sky’s brightest naked eye clusters are located near one another in sky.

Let’s return now to Aldebaran. Reach your fist out to the sky and look a little less than two fists to the left of and a little above Aldebaran to find the two stars that represent the tips of the Bull’s horns. Sky watchers in search of a modest challenge can try finding the Bull’s front legs look to the right and below the Hyades.

The association of a bull with the stars of Taurus is a very ancient one going back at least to the days of Mesopotamia circa 4000 B.C. In Babylon, it was the first constellation of the zodiac and known as the Heavenly Bull. Back then, Taurus marked the spot the sun occupied on the first day of spring or vernal equinox. Because of a slight wobbling in Earth’s axis called precession, the sun now sits in Taurus on the first day of summer. Any clear winter night, you can share this distant historical connection.

Follow Orion’s Belt and you won’t go wrong

Sunlight reflects off the windows of homes on Duluth's hillside shortly after sunrise Thursday. Photo: Bob King

I don’t get to see many sunrises, but an early morning photo shoot presented a rare opportunity to watch the orange ball rise over the planet’s rim. I like my sunrises in peaceful places generally, but found myself off a freeway exit instead. It was quick and offered an elevated view. Nearly as enjoyable as the sun were its multitude reflections off the windows of homes perched on the hillside above downtown Duluth. Sunbeams were everywhere.

If you’re used to staying up and watching the stars rise, culminate in the southern sky and drop down in the west, the sun seems like just another star in the nightly progression of celestial sights from dusk until dawn. Its rising, while a spectacle, is expected, natural and woven into the flow of things as much as Sirius, Vega and the Big Dipper are.

The moon is now in gibbous or 3/4 phase, that time between first quarter and full. Need light to ski at night? Let the moon be your spotlight. Well to the east of the moon, Orion the Hunter climbs the southeastern sky and is easily seen around 9:30 and later.

Using Orion's Belt, you can easily find four of the winter sky's brightest stars. Created with Stellarium

There’s no better guide to navigating your way to new stars and constellations than Orion’s distinctive “three stars in a row” or Belt. Shoot a line through the Belt upward and you’ll run into the pinkish Aldebaran, the “alpha” or brightest star in Taurus the Bull. Shoot a line in the opposite direction and you’ll spear Sirius, the alpha star in Canis Major the Greater Dog. Perpendicular to the Belt are Orion’s two brightest stars: Betelgeuse and Rigel. If you’re not familiar with these stars, this is a perfect time to get acquainted. They’re bright enough to be unaffected by moonlight or moderate light pollution. Knowing where they are in the sky will help down the road as we explore sights – naked eye, binocular and telescope – in the upcoming winter season. You’ll also get a kick out of Sirius (SEER-ee-us), which sparkles like no other star. Its low elevation coupled with its extreme brightness makes it more obviously affected by turbulent air than stars higher up. Look closely and you’ll see that Sirius both flickers and changes color rapidly – all atmospheric effects.

A circular feature in the remaining or residual south polar cap of Mars is partially coated with carbon dioxide frost. Click photo for hi res image. Credit: NASA/JPL/University of Arizona

I thought you’d appreciate a truly unearthly solar system landscape in this photo of Mars’ south polar region shot recently by the eagle-eyed Mars Reconnaissance Orbiter. At center is a 2 1/2 mile diameter depression near the edge of the south polar cap that could be an impact crater. All the white areas around the feature are covered in bitter cold carbon dioxide frost. The areas at upper right and strung along the left are called “swiss cheese terrain” because of their rounded, holey contours. Contrary to first impressions, these white areas are large slabs of dry ice (frozen carbon dioxide) from 10 to 30 feet thick that stand higher than the surrounding terrain. As the sun warms the surface, ice vaporizes directly into a gas, opening up dark “islands” of surface rock. During the Martian fall season, as temperatures drop, the carbon dioxide re-condenses out of the atmosphere, returning to the surface as ice.