Fall's lessening daylight stimulates trees to break down the green chlorophyll in their leaves, exposing orange pigments called carotinoids that have been there all along. A different pigment, anthocyanin, colors these red maple leaves a brilliant shade of scarlet. Scientists aren't sure why trees produce the pigment in fall, but it may serve as an antioxidant, a bird attractor to help in the dispersal of seeds or simply to warm the leaf to protect it from the cold. Contributed / Bob King

Astro Bob 3:57 pm, Sep. 21, 2021

Astro Bob: Embrace the Equinox

Felicitous equinox, everyone! Fall starts on Wednesday, Sept. 22 at 2:20 p.m. Central Time, the moment the sun stands poised over Earth's equator.

The full Harvest Moon will rise nearly due east around sunset on Monday night, September 20th. Contributed / Bob King

Astro Bob 1:04 pm, Sep. 19, 2021

Astro Bob: Soak up the Harvest Moon's bountiful light

Have you ever seen Jupiter light up the clouds? The brilliant sun does this all the time but so can bright planets. On a recent night, I watched Jupiter "hollow out" a glowing aureole of light in a bank of incoming clouds. Saturn is at right. Later this week, the moon will be in conjunction with both planets.
Contributed / Bob King

Astro Bob 5:08 pm, Sep. 15, 2021

Astro Bob: Cozy conjunctions, ISS nights and laser Starlinks

Three overlapping craters form a Mickey Mouse outline on the waxing moon this evening and next, September 14-15, 2021. You'll need a small telescope to see it. Contributed / Virtual Moon Atlas

Astro Bob 4:02 pm, Sep. 14, 2021

Astro Bob: 'Aw, gee!' It's Mickey Mouse on the moon

Moons Ganymede and Europa cast shadows on Jupiter's cloud tops on March 25, 2019. Contributed / Damian Peach

Astro Bob 2:16 pm, Sep. 12, 2021

Astro Bob: Jupiter puts on a magic show Sunday night

NASA's Perseverance rover took this photo of the rock nicknamed "Rochette" on Tuesday, Sept. 7, 2021. It shows two holes where the rover's drill obtained chalk-size samples. The hole on the left side is known as "Montagnac" (drilled on Sept. 7), and the hole on the right is named "Montdenier" (drilled on Sept. 1).
Contributed / NASA, JPL-Caltech

Astro Bob 2:59 pm, Sep. 10, 2021

Astro Bob: Mars Mambo #2 — a little bit of 'Rochette' makes the day

There's a lot going on on the sun right now. NASA's Solar Dynamics Observatory took this image earlier today of four sunspot groups. Region 2866 is just large enough to be visible without a telescope when viewed through a appropriate, safe solar filter or using a projection method described in the text. Contributed / NASA, SDO

Astro Bob 5:25 pm, Sep. 7, 2021

Astro Bob: Sun gets a bad case of the spots

The moon will be new Monday evening, Sept. 6, 2021, and completely invisible near the sun in the constellation Leo.
Contributed / Stellarium

Astro Bob 2:22 pm, Sep. 6, 2021

Astro Bob: Metamorphosis at dusk — A New Moon revelation

Find the Teapot of Sagittarius and the bright chunk of Milky Way called the Large Sagittarius Star Cloud (upper right) that makes the "steam" rising from the kettle. Contributed / Bob King

Astro Bob 3:05 pm, Sep. 2, 2021

Astro Bob: Sagittarius — a pot of tea at twilight's end

The enormous mass of two foreground galaxies (center) act as a lens to bend and distort the light of a distant, star-like quasar into four images in a ring surrounding the pair. Contributed / ESA/Hubble & NASA, T. Treu; Acknowledgment: J. Schmidt

Astro Bob 7:54 pm, Sep. 1, 2021

Astro Bob: Gravitational magic creates cosmic quintuple

Active sunspot group 2860 unleashes a powerful M4.7 flare early on August 28th. We see it here up close in a photo taken in ultraviolet light by NASA's Solar Dynamics Observatory. Contributed / NASA, SDO

Astro Bob 1:03 pm, Aug. 29, 2021

Astro Bob: Aurora watch Sunday night, Aug. 29

The fastest asteroid in the solar system was recently discovered at NOIRLab’s CTIO. The orbit of the approximately 0.6-mile-wide asteroid takes it as close as 12 million miles from the sun every 113 days. This artist’s rendering shows the asteroid (above) and the planet Mercury (below).
Contributed / CTIO, NOIRLab, NSF, AURA, J. da Silva (Spaceengine)

Astro Bob 4:19 pm, Aug. 25, 2021

Astro Bob: Newly-discovered, fastest asteroid hotter than your oven

The bright asteroid Hebe is located just above the Teapot asterism that forms part of Sagittarius the Archer. It slowly tracks to the southeast now through fall. To get oriented, start at Saturn to point you to the general vicinity, then use the more detailed map below to star hop to the asteroid.
Contributed / Stellarium with additions by Bob King

Astro Bob 2:27 pm, Aug. 23, 2021

Astro Bob: Have a small scope? Take a peek at Hebe

The moon, photographed one day past full on Sunday, July 24, 2021, is anything but blue! Forest fires at the time fill the air with smoke, which dimmed and reddened the rising moon. Contributed / Bob King

Astro Bob 2:32 pm, Aug. 21, 2021

Astro Bob: Will the real Blue Moon please stand up?

Both Jupiter and Saturn brighten up the dim constellation Capricornus on Sunday, August 15. Jupiter rises around sunset and is easily visible in the southeastern sky by 9:30-10 p.m. local daylight time. Contributed / Bob King

Astro Bob 2:35 pm, Aug. 19, 2021

Astro Bob: Jupiter and Earth get tight tonight

The bright star Vega — pronounced either VEE-guh or VAY-guh — shines from near the top of the sky in August 2019.
Contributed / Bob King

Astro Bob 6:00 pm, Aug. 17, 2021

Astro Bob: Lie back in the grass and experience Vega

A Perseid fireball streaks past the Pleiades (Seven Sisters) star cluster during the surprise outburst shortly before dawn on August 14. (Bob King)

Astro Bob 2:31 pm, Aug. 15, 2021

Astro Bob: Perseid meteor shower surprises with post-peak outburst

William Wiethoff of Port Wing, Wisconsin, captured this bright Perseid against the Milky Way during the 2018 shower.
Contributed / William Wiethoff

Astro Bob 12:47 pm, Aug. 11, 2021

Astro Bob: How to photograph Perseid meteors

RS Ophiuchi shines brightly at magnitude 5.0 in this photo taken on August 9, 2021. The nova explosion is faintly visible with the naked eye as soon as it gets dark. Contributed / Ernesto Guido, Marco Rocchetto & Adriano Valvasori / telescope.live

Astro Bob 5:53 pm, Aug. 9, 2021

Astro Bob: A naked-eye starburst in Ophiuchus

A brilliant Perseid fireball cuts a colorful trail across the sky on the night of August 11-12, 2016. If you're lucky you might see similar brilliant Perseids speeding across the sky this week.
Contributed / Siaraduz / CC BY-SA 4.0

Astro Bob 4:23 pm, Aug. 8, 2021

Astro Bob: The Perseid meteor shower brings joy this week

The funnel weaver spider builds a flat, sheet-like web that funnels to a hole near its center. The spider occupies the hole in wait of prey. (Bob King)

Astro Bob 2:58 pm, Aug. 5, 2021

Astro Bob: A spider's lesson in black holes and spacetime

Orion returns to the morning sky at dawn in late July-early August. Wednesday morning August 4th, the old crescent moon joins the scene. (Stellarium)

Astro Bob 4:09 pm, Aug. 3, 2021

Astro Bob: Orion's rising hints of the coming fall

Saturn's rings are tilted toward us and make a memorable sight in a modest telescope this month. This photo was taken on July 21, 2021. (Damian Peach)

Astro Bob 4:22 pm, Aug. 1, 2021

Astro Bob: See Saturn at its most spectacular

The moon, one night before last quarter phase, will clear the trees around 12:30 a.m. tomorrow morning, July 30th. Will you be awake to see it? (Stellarium)

Astro Bob 4:20 pm, Jul. 29, 2021

Astro Bob: The Loneliness of the Last Quarter Moon

A Proton rocket carrying the Nauka module lifts off from the Baikonur Cosmodrome on July 21st headed for the International Space Station. (Roscosmos)

Astro Bob 2:20 pm, Jul. 28, 2021

Astro Bob: Watch 'Nauka' catch the space station

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