SOLAR MINIMUM CONDITIONS ARE IN EFFECT: The sun has been without spots for 17 consecutive days--a sign that Solar Minimum is underway. Many people think Solar Minimum is uninteresting. Not so. This phase of the solar cycle brings extra cosmic rays, long-lasting holes in the sun's atmosphere, and a possible surplus of noctilucent clouds. Aurora Alerts: SMS text
IS STARLINK A DISASTER FOR ASTRONOMY? Last May, Elon Musk of SpaceX wrote: "Starlink won't be seen by anyone unless looking very carefully & will have ~0% impact on advancements in astronomy." Here is the latest evidence to the contrary. On Nov. 26th, Alan Conrad video recorded a naked-eye "Starlink meteor shower" over his home in Liverpool, Nova Scotia:
"The satellites flew overhead between 5 am and 6 am local time," says Conrad. "They were about as bright as 3rd magnitude stars."
Starlink is a venture by SpaceX. The idea is to launch 12,000 or more satellites into Earth orbit, surrounding our planet and providing global internet coverage even to people in remote areas. The first batch of 60 Starlink satellites launched in May 2019 surprised astronomers and prompted the International Astronomical Union to issue a statement of concern. Filling the sky with thousands of artificial stars might not be good for astronomy, they suggested.
The satellites Conrad recorded were from the 2nd batch of 60 launched in Nov. 2019. They are fading somewhat as the ascend to their operational orbits more than 500 km high. Even at that altitude, however, satellites from the first Starlink launch in May remain visible at magnitudes ranging from +4 (naked-eye) to +7 (easy for telescopes). The 2nd batch will remain visible as well.
Is Starlink a disaster for astronomy? "Disaster" does come from ancient Greek words meaning "bad star".... This is how Elon Musk can fix the damage.
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SCINTILLATING SIRIUS: Sirius is the brightest star in the sky and, as a result , the most colorful. At this time of year, the Dog Star produces a veritable spray of rainbow colors as it hangs low in the eastern sky after sunset. Roy Spencer of Huntsville, AL, has developed a beautiful way to record it. "I manually jiggled my camera while I was photographing Sirius, spreading its colors around," he explains.
"This de-focused 5 sec exposure was when the star was at elevation of 15 deg," says Spencer.
Astronomers call this phenomenon "scintillation." Also known as "twinkling," it is caused by thermal irregularities in Earth's atmosphere. As packets of relatively warm and cool air drift in front of Sirius, the star's light is refracted. The prismatic action of these air packets produce rainbow colors--especially near the horizon where starlight must pass through many turbulent irregularities to reach the observer.
ANNIE JUMP CANNON IN THE STRATOSPHERE: Pioneering astronomer Annie Jump Cannon invented the modern system of stellar classification. To honor her, the US Mint has created a $1 American Innovation coin featuring Cannon's silhouette and a spray of stars. On Nov. 11th, the students of Earth to Sky Calculus flew some to the stratosphere, 111,221 feet above the Sierra Nevada mountains of central California:
You can have a roll of 25 for $149.95. The students are selling the coins to support their cosmic ray ballooning program. Each roll contains 25 one dollar coins with uncirculated finishes. Cannon is shown on one side and the Statue of Liberty on the other. Individual coins make great Christmas stocking stuffers for young scientists--or give the whole roll as a special gift. Your order comes with a greeting card showing the coins in flight.
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