Yesterday there was a total solar eclipse visible only at the end of the Earth. To capture the unusual phenomenon, airplanes took flight below the clouded seascape of Southern Ocean. The featured image shows one relatively spectacular capture where the bright spot is the outer corona of the Sun and the eclipsing Moon is seen as the dark spot in the center. A wing and engine of the airplane are visible across the left and bottom of the image, while another airplane observing the eclipse is visible on the far left. The dark area of the sky surrounding the eclipsed Sun is called a shadow cone. It is dark because you are looking down a long corridor of air shadowed by the Moon. A careful inspection of the eclipsed Sun will reveal the planet Mercury just to the right. The next total solar eclipse shadow will cross parts of Australia and Indonesia in April of 2023, while the one after that will cross North America in April of 2024. Notable Eclipse Submissions to APOD: Total Solar Eclipse of 2021 December
In this snapshot from November 18, the Full Moon was not far from Earth’s shadow. In skies over Sicily the brightest lunar phase was eclipsed by passing clouds though. The full moonlight was dimmed and momentarily diffracted by small but similar sized water droplets near the edges of the high thin clouds. The resulting iridescence shines with colors like a lunar corona. On that night, the Full Moon was also seen close to the Pleiades star cluster appearing at the lower left of the iridescent cloud bank. The stars of the Seven Sisters were soon to share the sky with a darker, reddened lunar disk.
Sweeping through northern predawn skies, on November 24 Comet Leonard (C/2021 A1) was caught between two galaxies in this composite telescopic image. Sporting a greenish coma the comet’s dusty tail seems to harpoon the heart of NGC 4631 (top) also known as the Whale Galaxy. Of course NGC 4631 and NGC 4656 (bottom, aka the Hockey Stick) are background galaxies some 25 million light-years away. On that date the comet was about 6 light-minutes from our fair planet. Its closest approach to Earth (and even closer approach to Venus) still to come, Comet Leonard will grow brighter in December. Already a good object for binoculars and small telescopes, this comet will likely not return to the inner Solar System. Its perihelion, or closest approach to the Sun, will be on January 3, 2022.
Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small galaxies form stars too, like nearby NGC 6822, also known as Barnard’s Galaxy. Beyond the rich starfields in the constellation Sagittarius, NGC 6822 is a mere 1.5 million light-years away, a member of our Local Group of galaxies. A dwarf irregular galaxy similar to the Small Magellanic Cloud, NGC 6822 is about 7,000 light-years across. Brighter foreground stars in our Milky Way have a spiky appearance. Behind them, Barnard’s Galaxy is seen to be filled with young blue stars and mottled with the telltale pinkish hydrogen glow of star forming regions in this deep color composite image.
What causes a blue band to cross the Moon during a lunar eclipse? The blue band is real but usually quite hard to see. The featured HDR image of last week’s lunar eclipse, however — taken from Yancheng, China — has been digitally processed to equalize the Moon’s brightness and exaggerate the colors. The gray color of the bottom right is the Moon’s natural color, directly illuminated by sunlight. The upper left part of the Moon is not directly lit by the Sun since it is being eclipsed — it in the Earth’s shadow. It is faintly lit, though, by sunlight that has passed deep through Earth’s atmosphere. This part of the Moon is red — and called a blood Moon — for the same reason that Earth’s sunsets are red: because air scatters away more blue light than red. The unusual blue band is different — its color is created by sunlight that has passed high through Earth’s atmosphere, where red light is better absorbed by ozone than blue. A total eclipse of the Sun will occur this weekend but, unfortunately, totality be visible only near the Earth’s South Pole. Almost Hyperspace: Random APOD Generator