ASTRONOMY - A Year of Sunrises

2022 January 5

A Year of Sunrises
Image Credit & Copyright: Luca Vanzella

Explanation: Does the Sun always rise in the same direction? No. As the months change, the direction toward the rising Sun changes, too. The featured image shows the direction of sunrise every month during 2021 as seen from the city of Edmonton, Alberta, Canada. The camera in the image is always facing due east, with north toward the left and south toward the right. As shown in an accompanying video, the top image was taken in 2020 December, while the bottom image was captured in 2021 December, making 13 images in total. Although the Sun always rises in the east in general, it rises furthest to the south of east on the December solstice, and furthest north of east on the June solstice. In many countries, the December Solstice is considered an official change in season: for example the first day of winter in the North. Solar heating and stored energy in the Earth's surface and atmosphere are near their lowest during winter, making the winter season the coldest of the year.

ASTRONOMY - Moons behind rings of Saturn

 2022 January 4

Moons Beyond Rings at Saturn
Image Credit: NASA, ESA, JPL, Cassini Imaging Team

Explanation: What's happened to that moon of Saturn? Nothing -- Saturn's moon Rhea is just partly hidden behind Saturn's rings. In 2010, the robotic Cassini spacecraft then orbiting Saturn took this narrow-angle view looking across the Solar System's most famous rings. Rings visible in the foreground include the thin F ring on the outside and the much wider A and B rings just interior to it. Although it seems to be hovering over the rings, Saturn's moon Janus is actually far behind them. Janus is one of Saturn's smaller moons and measures only about 180 kilometers across. Farther out from the camera is the heavily cratered Rhea, a much larger moon measuring 1,500 kilometers across. The top of Rhea is visible only through gaps in the rings. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn's atmosphere, where it surely melted.

ASTRONOMY - Comet Leonard's Long Tail

 2022 January 3

Comet Leonard's Long Tail
Image Credit & Copyright: Jan Hattenbach

Explanation: You couldn't see Comet Leonard’s extremely long tail with a telescope — it was just too long. You also couldn't see it with binoculars — still too long. Or with your eyes -- it was too dim. Or from a city — the sky was too bright. But from a dark location with a low horizon — your camera could. And still might -- if the comet survives today's closest encounter with the Sun, which occurs between the orbits of Mercury and Venus. The featured picture was created from two deep and wide-angle camera images taken from La Palma in the Canary Islands of Spain late last month. Afterwards, if it survives, what is left of Comet Leonard's nucleus will head out of our Solar System, never to return.

ASTRONOMIE - Tout comprendre sur le soleil

Le Soleil

ASTRONOMY - Quadruple Lunar Halo Over Winter Road

 2022 January 2

Quadruple Lunar Halo Over Winter Road
Image Credit & Copyright: Dani Caxete

Explanation: Sometimes falling ice crystals make the atmosphere into a giant lens causing arcs and halos to appear around the Sun or Moon. One Saturday night in 2012 was just such a time near Madrid, Spain, where a winter sky displayed not only a bright Moon but four rare lunar halos. The brightest object, near the top of the featured image, is the Moon. Light from the Moon refracts through tumbling hexagonal ice crystals into a somewhat rare 22-degree halo seen surrounding the Moon. Elongating the 22-degree arc horizontally is a more rare circumscribed halo caused by column ice crystals. Even more rare, some moonlight refracts through more distant tumbling ice crystals to form a (third) rainbow-like arc 46 degrees from the Moon and appearing here just above a picturesque winter landscape. Furthermore, part of a whole 46-degree circular halo is also visible, so that an extremely rare -- especially for the Moon -- quadruple halo was captured. Far in the background is a famous winter skyscape that includes Sirius, the belt of Orion, and Betelgeuse -- visible between the inner and outer arcs. Halos and arcs typically last for minutes to hours, so if you do see one there should be time to invite family, friends or neighbors to share your unusual lensed vista of the sky.

MUSIC - Herbert Von Karajan & Vienna Phillarmonic Orchestra - Radetzky March

"Radetzky March"

ASTRONOMY - Plane Crossing a Crescent Moon

 2019 February 12

Plane Crossing a Crescent Moon
Image Credit & Copyright: Olivier Staiger (Binounistan.com)

Explanation: No, this is not a good way to get to the Moon. What is pictured is a chance superposition of an airplane and the Moon. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright red hue. Far in the distance, well behind the plane, is a crescent Moon, also slightly reddened. Captured a month ago above Valais, Switzerland, the featured image was taken so soon after sunset that planes in the sky were still in sunlight, as were their contrails. Within minutes, unfortunately, the impromptu sky show ended. The plane crossed the Moon and moved out of sight. The Moon set. The contrail became unilluminated and then dispersed.

Happy new year !

 

💓😔💓

ASTRONOMY - JWST on the Road to L2

 2021 December 31

JWST on the Road to L2
Image Credit & Copyright: Malcolm Park (North York Astronomical Association)

Explanation: This timelapse gif tracks the James Webb Space Telescope as it streaks across the stars of Orion on its journey to a destination beyond the Moon. Recorded on December 28, 12 consecutive exposures each 10 minutes long were aligned and combined with a subsequent color image of the background stars to create the animation. About 2.5 days after its December 25 launch, JWST cruised past the altitude of the Moon's orbit as it climbed up the gravity ridge from Earth to reach a halo orbit around L2, an Earth-Sun Lagrange point. Lagrange points are convenient locations in space where the combined gravitational attraction of one massive body (Earth) orbiting another massive body (Sun) is in balance with the centripetal force needed to move along with them. So much smaller masses, like spacecraft, will tend to stay there. One of 5 Lagrange points, L2 is about 1.5 million kilometers from Earth directly along the Earth-Sun line. JWST will arrive at L2 on January 23, 29 days after launch. While relaxing in Earth's surface gravity you can follow the James Webb Space Telescope's progress and complicated deployment online.

ASTRONOMY - The Further Tail of Comet Leonard

 2021 December 30

The Further Tail of Comet Leonard
Image Credit & Copyright: Daniele Gasparri

Explanation: Comet Leonard, brightest comet of 2021, is at the lower left of these two panels captured on December 29 in dark Atacama desert skies. Heading for its perihelion on January 3 Comet Leonard's visible tail has grown. Stacked exposures with a wide angle lens (also displayed in a reversed B/W scheme for contrast), trace the complicated ion tail for an amazing 60 degrees, with bright Jupiter shining near the horizon at lower right. Material vaporizing from Comet Leonard's nucleus, a mass of dust, rock, and ices about 1 kilometer across, has produced the long tail of ionized gas fluorescing in the sunlight. Likely flares on the comet's nucleus and buffeting by magnetic fields and the solar wind in recent weeks have resulted in the tail's irregular pinched and twisted appearance. Still days from its closest approach to the Sun, Comet Leonard's activity should continue. The comet is south of the Solar System's ecliptic plane as it sweeps through the southern constellation Microscopium.