Saturn stationary in Libra on August 2

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Astronomical almanacs list the planet Saturn as stationary on August 2 at 20 Universal Time. That is 3 p.m. on August 2 for us in central North America. Convert to your time zone.

What does it mean? It doesn’t mean that Saturn – like Polaris, the North Star – will remain in the same place in the sky all through the night tonight. For most skywatchers, most everywhere on Earth, Saturn will appear at its highest in the sky around sunset. It’ll descend westward, to set in the west around midnight (1 a.m. local daylight-saving time) at mid-northern latitudes, and after midnight at more southerly latitudes. This movement of Saturn across the sky throughout the night is due to Earth’s spin on its rotational axis.

And it doesn’t mean, of course, that Saturn stops moving in space. In space, nothing ever stops moving.

Instead, the “stationary point” is an Earth-centered illusion.

It means that – on August 2, 2015 – Saturn is poised in one spot relative to the background stars. It’s in front of the constellation Libra, momentarily motionless relative to Libra’s third-magnitude stars Zubenelgenubi and Zubeneschamali – as well as to the first-magnitude star Antares in the constellation Scorpius.

Since March 14, Saturn has been moving in retrograde (westward in front of the stars). As seen on our sky’s dome, it moved out of the constellation Scorpius and into the constellation Libra in mid-March. After today, Saturn will reverse course and begin moving prograde (eastward in front of the stars), toward the constellation Scorpius once again.

This apparent movement of Saturn, first to the west and then to the east, is actually due to Earth’s motion in orbit around the sun. We move faster than Saturn – on an inner track around the sun – and that’s why Saturn appears to hang motionless at times, prior to changing its apparent direction of motion on our sky’s dome. It’s as if we are in a fast car, moving along a highway. From our perspective, slower cars can, for a time, appear to move backwards in contrast to the distant landscape.

Saturn is the most distant world you can easily see with the unaided eye. As a result, it moves rather slowly through the constellations of the Zodiac. Yet Saturn, the sixth planet outward from the sun, will finally leave Libra to move back into the constellation Scorpius in October 2015.

Keep an eye on Saturn and the Scorpion’s bright star Antares. How long will it take for you to discern Saturn’s change of position relative to Antares, a key star of the Zodiac?

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As always, the planet Saturn is found upon the Zodiac – the great belt of stars that follows the ecliptic, or the sun’s annual path, across the sky. The planets are always found on or near the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac.

Bottom line: The golden planet Saturn is stationary – not moving with respect to the backdrop stars – on August 2, 2015. A planet’s “stationary point” doesn’t mean it stops moving in space. In space, nothing ever stops moving. Instead, the “stationary point” is an Earth-centered illusion.

Saturn dominates in August 2015 night sky

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Meteor season is here! When to watch.

Astronomical almanacs list the planet Saturn as stationary on August 2 at 20 Universal Time. That is 3 p.m. on August 2 for us in central North America. Convert to your time zone.

What does it mean? It doesn’t mean that Saturn – like Polaris, the North Star – will remain in the same place in the sky all through the night tonight. For most skywatchers, most everywhere on Earth, Saturn will appear at its highest in the sky around sunset. It’ll descend westward, to set in the west around midnight (1 a.m. local daylight-saving time) at mid-northern latitudes, and after midnight at more southerly latitudes. This movement of Saturn across the sky throughout the night is due to Earth’s spin on its rotational axis.

And it doesn’t mean, of course, that Saturn stops moving in space. In space, nothing ever stops moving.

Instead, the “stationary point” is an Earth-centered illusion.

It means that – on August 2, 2015 – Saturn is poised in one spot relative to the background stars. It’s in front of the constellation Libra, momentarily motionless relative to Libra’s third-magnitude stars Zubenelgenubi and Zubeneschamali – as well as to the first-magnitude star Antares in the constellation Scorpius.

Since March 14, Saturn has been moving in retrograde (westward in front of the stars). As seen on our sky’s dome, it moved out of the constellation Scorpius and into the constellation Libra in mid-March. After today, Saturn will reverse course and begin moving prograde (eastward in front of the stars), toward the constellation Scorpius once again.

This apparent movement of Saturn, first to the west and then to the east, is actually due to Earth’s motion in orbit around the sun. We move faster than Saturn – on an inner track around the sun – and that’s why Saturn appears to hang motionless at times, prior to changing its apparent direction of motion on our sky’s dome. It’s as if we are in a fast car, moving along a highway. From our perspective, slower cars can, for a time, appear to move backwards in contrast to the distant landscape.

Saturn is the most distant world you can easily see with the unaided eye. As a result, it moves rather slowly through the constellations of the Zodiac. Yet Saturn, the sixth planet outward from the sun, will finally leave Libra to move back into the constellation Scorpius in October 2015.

Keep an eye on Saturn and the Scorpion’s bright star Antares. How long will it take for you to discern Saturn’s change of position relative to Antares, a key star of the Zodiac?

EarthSky astronomy kits are perfect for beginners. Order yours today.

As always, the planet Saturn is found upon the Zodiac – the great belt of stars that follows the ecliptic, or the sun’s annual path, across the sky. The planets are always found on or near the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac.

Bottom line: The golden planet Saturn is stationary – not moving with respect to the backdrop stars – on August 2, 2015. A planet’s “stationary point” doesn’t mean it stops moving in space. In space, nothing ever stops moving. Instead, the “stationary point” is an Earth-centered illusion.

Saturn dominates in August 2015 night sky

Help support posts like these at the EarthSky store. Fun astronomy gifts and tools for all ages!

from EarthSky http://ift.tt/1eLdmvg