The Winter Hexagon is the gem of the winter sky. (Stellarium)

Astro Bob Jan 24th 2021 - 2pm

Astro Bob: Stroll with the moon through the Winter Hexagon

Sunday through Tuesday nights, January 24-26, the bright moon will guide you to one of the sky's most sparkling sights.

The sharp dot in the middle of the picture is the Surveyor 2 rocket booster photographed during its close flyby of Earth on Dec. 1, 2020. The stars are trailed because the telescope tracked the fast-moving object. The inset at upper left captured a series of bright and faint flashes as the booster rotated (tumbled) during the 60-second exposure. (Gianluca Masi)

Astro Bob Jan 21st 2021 - 5pm

Astro Bob: Artificial mini-moon, 2020 SO, says hello and then goodbye

The International Space Station orbits about 250 miles (400 km) above the Earth and travels at 17,100 mph (27,600 km/hour), completing one orbit every 90 minutes. (NASA)

Astro Bob Jan 19th 2021 - 7pm

Astro Bob: Evenings with the ISS

Sirius, also called the Dog Star because it's the brightest luminary in Canis Major the Greater Dog, is the most vividly twinkling star in the sky. It rises near the end of evening twilight in the southeastern sky. (Bob King)

Astro Bob Jan 17th 2021 - 9pm

Astro Bob: A Sirius look at twinkling stars

The young moon joins Mercury on Thursday evening, Jan. 14 at dusk. If you're lucky you might still catch a last glimpse of Jupiter. (Stellarium)

Astro Bob Jan 14th 2021 - 12pm

Astro Bob: Mercury warms up January nights

With the help of Mars we can find the constellation Aries the Ram, here depicted in Urania's Mirror by Jehoshaphat Aspin. (Public domain)

Astro Bob Jan 12th 2021 - 10am

Astro Bob: Hunt Aries and Triangulum with help from Mars

This is an artist's conception of Proxima Centauri b, a planet slightly bigger than the Earth, orbiting the red dwarf star Proxima Centauri. Proxima and the Alpha Centauri binary are seen in the background at left. Last spring, an Australian radio telescope recorded an unexplained radio signal emanating from the Proxima system. (ESO, M. Kornmesser)

Astro Bob Jan 10th 2021 - 7pm

Astro Bob: Was the Proxima Centauri signal sent by aliens?

As the Earth spins, stars appear to move slowly from east to west across the night sky. At right a time exposure shows the trails of stars in Orion's Belt and Sword across the southern sky. (Bob King)

Astro Bob Jan 7th 2021 - 2pm

Astro Bob: How to sense Earth's rotation, revolution in real time

During an aurora, particles from the sun zoom down along Earth's magnetic field lines and strike the atmosphere to form an oval of glowing light called the auroral oval. It's centered on the north geomagnetic pole which is offset about 10° from the geographic pole. The oval is permanent fixture for Arctic and Antarctic observers, but during large solar storms it expands southward and becomes visible across parts of the U.S. (NASA Goddard Space Flight Center)

Astro Bob Jan 5th 2021 - 1pm

Astro Bob: Northern lights possible Tuesday night Jan. 5-6

The sun may be low and set early in January, but we're closer to it now than at any other time of the year. (Bob King)

Astro Bob Jan 3rd 2021 - 4pm

Astro Bob: Seasonal variations — why winter gets the short end of the stick

A ray of light called a sun pillar appears above the setting sun on Dec. 30 in Duluth, Minn. Pillars form when sunlight reflects off the flat sides of ice crystals suspended in the air parallel to the ground. They reflect the light downward to our eyes like tiny mirrors. (Bob King)

Astro Bob Dec 31st 2020 - 3pm

Astro Bob: 2020 night-sky superlatives and what's coming in 2021

The full moon rises over Lake Superior at Brighton Beach in Duluth, Minn. on Nov. 30, 2020. A full moon shines opposite the sun, rises when the sun sets and shines all night until it set around sunrise the following morning. (Bob King)

Astro Bob Dec 29th 2020 - 12pm

Astro Bob: The Full Cold Moon has no wrinkles

Cooking chocolate bars in the microwave? Why not? It's a simple, homegrown way to find the speed of light. (Bob King)

Astro Bob Dec 28th 2020 - 3pm

Astro Bob: How to calculate the speed of light using your kitchen microwave

On December 21, sample catcher chambers in the Hayabusa2 landing capsule were opened and moved to the collection containers in the photo. Each black fragment is a piece of Ryugu, a potentially hazardous asteroid the orbits the sun near the Earth. The arrow points to a possible piece of aluminum from the sample collector itself that somehow wound up inside the container. 5mm = about one-fifth of an inch. The largest fragments are about 0.4 inch long. (Japan Aerospace Exploration Agency — JAXA)

Astro Bob Dec 25th 2020 - 1pm

Astro Bob: Scientists love 'lumps of coal' in their Christmas stockings

I watched Jupiter and Saturn's close conjunction last night (Dec. 21) from a farmer's field and took this photo when a truck drove by. (Bob King)

Astro Bob Dec 22nd 2020 - 6pm

Astro Bob: Not so fast! Jupiter-Saturn delight through Christmas

The sun rises with two sundogs in tow over the ice-encrusted shore of Lake Superior in Duluth. (Bob King)

Astro Bob Dec 20th 2020 - 2pm

Astro Bob: Winter solstice brings hope during the longest night of the year

The Jupiter-Saturn duo flirts with clouds on December 9. Jupiter is the brighter planet. (Bob King)

Astro Bob Dec 16th 2020 - 2pm

Astro Bob: Jupiter and Saturn approach their historic winter solstice Great Conjunction

A bright Geminid meteor streaks across the sky over Duluth, Minn. during the early morning of December 14th. (Bob King)

Astro Bob Dec 15th 2020 - 2pm

Astro Bob: Geminids a hit; December's dark days turn to light

Astro Bob Dec 13th 2020 - 2pm

Astro Bob: Watch the Dec. 14 total solar eclipse from home

A brilliant Geminid fireball meteor flares near Jupiter during the 2012 Geminid meteor shower. Orion is at left. (John Flannery / CC BY-SA 2.0)

Astro Bob Dec 11th 2020 - 8am

Astro Bob: Here come the Geminids! Best meteor shower of year

Humor meets caring in the era of COVID-19. (Rebecca Siegel)

Astro Bob Dec 7th 2020 - 2pm

Astro Bob: Hey, what's so funny? 55+ dubious astronomy jokes

A member of the recovery team transports the Hayabusa-2 sample capsule recovered from the Australian desert to a secure facility on Dec. 6. (Japan Aerospace Exploration Agency — JAXA)

Astro Bob Dec 6th 2020 - 3pm

Astro Bob: Asteroid samples successfully arrive on Earth

Taken a couple years ago, this photo shows a "picket fence" of rays associated with STEVE. The short streaks at the base of the rays are the mysterious green "cannonballs," point sources of glowing oxygen that are about 1,100 feet across. They're moving horizontally, the reason they appear as streaks during the time exposure. (Debra Ceravolo)

Astro Bob Dec 1st 2020 - 6pm

Astro Bob: Aurora-like STEVE spins off mysterious spheres of light

Seen here in far ultraviolet (UV) light, a powerful solar flare erupts on Nov. 29 from a new sunspot region located just beyond the sun's edge. The spidery shapes at right are hot gases cycling along magnetic lines of force in two sunspot groups. (NASA / SDO)

Astro Bob Nov 30th 2020 - 2pm

Astro Bob: Solar activity escalates with a major flare and lots of spots

The moon rises in penumbral eclipse over the Duluth Ship Canal on Feb. 10, 2017. Penumbral shading is visible over the left half the lunar disk. (Bob King)

Astro Bob Nov 29th 2020 - 2pm

Astro Bob: How to see the Nov. 30 lunar eclipse

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