Tonight – July 19, 2015 – soon after sunset, look west for the waxing crescent moon. Below the moon, not much above the horizon, you’ll see the brilliant planets Venus and Jupiter – the second-brightest and third-brightest celestial objects in the night sky, after the moon. As dusk deepens, you might even spot the star Regulus forming a triangle with these two blazing planets.
Be sure to look for the threesome – Venus, Jupiter and Regulus – at dusk and nightfall, for all three will follow the sun beneath the horizon by early evening.
The moon, Venus and Jupiter shine by reflecting the light of the sun. Regulus, being a star, shines by its own light.
Enjoying EarthSky so far? Sign up for our free daily newsletter today!
The moon and Venus display the full range of phases in Earth’s sky, while Jupiter always appears full as seen from Earth. The moon’s phases result from the moon revolving around Earth, while those of Venus result from Venus revolving around the sun. You need a telescope to observe Venus’ changing phases, but, if you had one, the next several weeks would be a wonderful time to watch, as Venus wanes in phase.
Remember, Venus orbits the sun inside of Earth’s orbit. Meanwhile, Jupiter orbits the sun five times the Earth’s distance from the sun, and that’s why Jupiter always remains at or near full phase from the vantage point on Earth. Meanwhile, when Venus is about to go between the Earth and sun – as it will next in mid-August – we see mostly the night side of Venus from Earth … a crescent Venus.
These next few to several weeks will present a good time for watch Venus through the telescope. As Venus moves toward passing between the Earth and sun in its smaller, faster orbit, the distance between Earth and Venus is decreasing. Telescope users can see that the disk of Venus is getting bigger. And, as Venus in its swifter orbit moves closer and closer to Earth on its inside track around the sun, Venus’ phase will wane … and wane some more.
On July 19, Venus disk appears about 18% illuminated by sunlight.
By the month’s end, Venus’ disk will only be about 7% illuminated.
Unlike Venus, which is waning in July evening sky, the moon is waxing toward full phase. In fact, when the moon turns full near the month’s end, many will celebrate the coming of the Blue Moon – the second of two full moons in a single calendar month.
At the same time, meteor-watchers will be celebrating, too. A full moon at the end of July means that we’ll have a very slender moon – or perhaps no moon at all – for the peak nights of August’s famous Perseid meteor shower. That will be the case this year, and it’s the reason you should get ready to watch for meteors! You’ll find EarthSky’s meteor shower guide for 2015, here.
Bottom line: This evening – July 19, 2015 – view the beautiful waxing crescent moon, the planets Venus and Jupiter – and possibly the star Regulus.
Donate: Your support means the world to us
EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store
from EarthSky http://ift.tt/1Jq1JCh
Tonight – July 19, 2015 – soon after sunset, look west for the waxing crescent moon. Below the moon, not much above the horizon, you’ll see the brilliant planets Venus and Jupiter – the second-brightest and third-brightest celestial objects in the night sky, after the moon. As dusk deepens, you might even spot the star Regulus forming a triangle with these two blazing planets.
Be sure to look for the threesome – Venus, Jupiter and Regulus – at dusk and nightfall, for all three will follow the sun beneath the horizon by early evening.
The moon, Venus and Jupiter shine by reflecting the light of the sun. Regulus, being a star, shines by its own light.
Enjoying EarthSky so far? Sign up for our free daily newsletter today!
The moon and Venus display the full range of phases in Earth’s sky, while Jupiter always appears full as seen from Earth. The moon’s phases result from the moon revolving around Earth, while those of Venus result from Venus revolving around the sun. You need a telescope to observe Venus’ changing phases, but, if you had one, the next several weeks would be a wonderful time to watch, as Venus wanes in phase.
Remember, Venus orbits the sun inside of Earth’s orbit. Meanwhile, Jupiter orbits the sun five times the Earth’s distance from the sun, and that’s why Jupiter always remains at or near full phase from the vantage point on Earth. Meanwhile, when Venus is about to go between the Earth and sun – as it will next in mid-August – we see mostly the night side of Venus from Earth … a crescent Venus.
These next few to several weeks will present a good time for watch Venus through the telescope. As Venus moves toward passing between the Earth and sun in its smaller, faster orbit, the distance between Earth and Venus is decreasing. Telescope users can see that the disk of Venus is getting bigger. And, as Venus in its swifter orbit moves closer and closer to Earth on its inside track around the sun, Venus’ phase will wane … and wane some more.
On July 19, Venus disk appears about 18% illuminated by sunlight.
By the month’s end, Venus’ disk will only be about 7% illuminated.
Unlike Venus, which is waning in July evening sky, the moon is waxing toward full phase. In fact, when the moon turns full near the month’s end, many will celebrate the coming of the Blue Moon – the second of two full moons in a single calendar month.
At the same time, meteor-watchers will be celebrating, too. A full moon at the end of July means that we’ll have a very slender moon – or perhaps no moon at all – for the peak nights of August’s famous Perseid meteor shower. That will be the case this year, and it’s the reason you should get ready to watch for meteors! You’ll find EarthSky’s meteor shower guide for 2015, here.
Bottom line: This evening – July 19, 2015 – view the beautiful waxing crescent moon, the planets Venus and Jupiter – and possibly the star Regulus.
Donate: Your support means the world to us
EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store
from EarthSky http://ift.tt/1Jq1JCh
Aucun commentaire:
Enregistrer un commentaire