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Beautiful zodiacal light! Photos and explanations., page 1

Topic started on 23-2-2012 @ 02:24 AM by elevenaugust
What is zodiacal light?

The Zodiacal light is composed of fine particles of dust in orbit around the sun and is visible because of scattered sunlight from the particles. The glow is brightest toward the sun from particles with diameters between a couple of micrometers and a few millimeters.

Two fundamental planes of planet Earth's sky compete for attention in this remarkable wide-angle vista, recorded on January 23rd. Arcing above the horizon and into the night at the left is a beautiful band of Zodiacal Light - sunlight scattered by dust in the solar system's ecliptic plane. Its opponent on the right is composed of the faint stars, dust clouds, and nebulae along the plane of our Milky Way Galaxy. Both celestial bands stand above the domes and towers of the Teide Observatory on the island of Tenerife. Also out to play in the pristine, dark skies over the Canary Islands, are brilliant Venus (lower left), the distant Andromeda Galaxy (near center), and the lovely Pleiades star cluster (top center). Of course, seasoned skygazers might even spot M33, the California Nebula, IC1805, and the double star cluster of Perseus. (Need some help? Just slide your cursor over the picture.)

From the mid-northern latitudes, the Zodiacal light is most easily visible from a dark location under clear and transparent skies just after evening twilight in the west in February and March, and in the morning eastern sky, just before the start of twilight in October. It is best seen at these times because the plane of dust that comprises it lies in the same plane as the ecliptic, and the ecliptic is at it's steepest angle to the horizon at these times of the year.

This image beautifully captures the zodiacal light, a triangular glow seen best in night skies free of overpowering moonlight and light pollution. The photograph was taken at ESO’s La Silla Observatory in Chile in September 2009, facing west some minutes after the Sun had set. A sea of clouds has settled in the valley below La Silla, which sits at an altitude of 2400 metres, with lesser peaks and ridges poking through the mist.

Many people confuse the Zodiacal light with twilight since it occurs in roughly the same area of sky, although careful attention to the time of the true end of astronomical twilight will remove any doubt about whether you are seeing the Zodiacal light or the sky brightening from lingering twilight.


Since the band of dust that forms the Zodiacal light completely circles the sun, it actually stretches across the entire night sky. At the anti-solar point, that point in the sky exactly opposite the sun in the sky, lies a very subtle, and very faint brightening of the dust called the Gegenschein, which is German for "counter-glow". Due to a phase effect similar to the increased brightness of the full moon, this brightening may also be helped by a concentration of dust at the L3 Lagrangian point. The Gegenschein is connected to the Zodiacal light by an even fainter portion of the dust called the Zodiacal bridge or band, and is extremely difficult to see. The Gegenschein is most easily seen at midnight when it is highest in the sky, and in those times of the year when it is in a part of the sky with few stars from late September to early November in Pices, and from late January to early February in Cancer.

The dust between the planets, that scatters sunlight our way, is not from the asteroid belt (green), but from periodic comets that spend much of their time near the orbit of Jupiter. (Credit: SWRI/SETI (Andrew Blanchard, David Nesvorny and Peter Jenniskens))

Interestingly, the Zodiacal light and Gegenschein can only be seen with the unaided eye, and not through any optical instruments such as binoculars or telescopes because of it's large size and low surface brightness. Parts of this cloud of interplanetary dust are also visible when the larger particles enter the Earth's atmosphere as meteors.

Like the zodiacal light, the gegenschein is sunlight reflected by interplanetary dust. Most of this dust is orbiting the Sun in about the ecliptic plane, with a possible concentration of particles at the L2 Earth–Sun Lagrangian point.
It is distinguished from zodiacal light by its high angle of reflection of the incident sunlight on the dust particles. It forms a slightly more luminous, oval glow directly opposite the Sun within the band of luminous zodiacal light. The intensity of the gegenschein is (relatively) enhanced because each dust particle is seen in full phase.


Stunning views of the zodiacal light:

Venus and Jupiter are this month's two brightest planets. Shortly after sunset on February 20, they dominate the sky above the western horizon and this snowy landscape. In clear and transparent skies over Cherry Springs State Park, Pennsylvania, USA, they are also seen immersed in Zodiacal light. The extended, diffuse, triangular glow is sunlight scattered by dust along the plane of the ecliptic. Brighter near the horizon, the Zodiacal glow angles upward, first to Venus and then to Jupiter hugging the ecliptic as they orbit the Sun.
Fading even further, the glow stretches toward the lovely Pleides star cluster near the top of the frame. Following their appearance in this Zodiacal skyscape, the coming days will see Venus and Jupiter sharing the early evening sky with a young crescent Moon. The two bright planets are even headed for a close pairing or conjunction, separated by about 3 degrees on March 13.

SOURCE: Stéphane Guisard from Astrosurf

Note: the last link above really worth a visit as you can see hi resolution pictures of the zodiacal light, in all sky fish eye view, with the constellations lines and names, as well as a 360° panoramic view with Paranal Observatory, Orion, Big deeper, Scorpius, Milky Way and zodiacal light.

Another SOURCE: Astropix

Zodiacal light Google mozaic
edit on 23-2-2012 by elevenaugust because: add sources


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