Tonight – the 46th anniversary of the first human footsteps on the moon – let the waxing crescent moon in the west after sunset teach you some things about skywatching. A useful concept for beginning skywatchers is that of the ecliptic – or path of the sun, moon and planets across our sky. We all know the ecliptic because it’s the path the sun follows throughout the year. But if you can visualize the ecliptic at night, it can help you find planets! Tonight – July 20, 2015 – notice that the illuminated part of the waxing crescent moon points into the ecliptic pathway, and it points toward the planets Venus and Jupiter.
On a waxing moon, the illuminated portion of the moon always points westward – toward the direction of sunset.
Because Venus and Jupiter lie to the west of tonight’s moon, the illuminated part of the lunar crescent points in the direction of these dazzling planets. As evening twilight starts to darken the sky, look for Venus and Jupiter below the moon and rather close to the horizon. Be sure to seek these brilliant worlds at dusk and nightfall, because they’ll follow the sun beneath the horizon by early evening.
If you have binoculars, you might also spot the star Regulus in the vicinity of these dazzling planets.
In the chart below, we expand the view of the July 20 sky to include Spica, the brightest star in the constellation Virgo the Maiden. The dark side of the waxing crescent moon always points eastward, in the moon’s direction of travel relative to the backdrop stars (and planets).
Look for the first quarter moon to pair up with Spica on July 23.
For illustrative purposes, the moon appears larger than it does in the actual sky. The green line depicts the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac. Regulus is the brightest star in the constellation Leo the Lion, and Spica is the brightest in the constellation Virgo the Maiden.
Both Venus and Jupiter are sinking closer to the glare of sunset throughout July, 2015. In fact, Venus and Jupiter will pass out of the evening sky and into the morning sky this August. If you’re an early riser, you’ll probably see Venus glorifying the eastern dawn by late August. You’ll likely spot Jupiter in the eastern morning twilight sometime in September.
Venus and Jupiter will adorn in the morning sky for the rest of 2015, and they’ll rendezvous for a beautiful conjunction in the predawn and dawn sky on October 26, 2015. Circle that date on your calendar!
Venus and Jupiter are the third-brightest and fourth-brightest celestial luminaries, respectively, after the sun and moon.
To cap things off on the night of July 20, see if the moon’s dark side is still aglow in earthshine – sunlight twice-reflected from Earth to the moon, and then the moon back to Earth. The earthshine may be easier to see through binoculars than the unaided eye.
Bottom line: On the evening of July 20, 2015, the illuminated portion of the waxing crescent moon point into the pathway of the ecliptic, or path of the sun, moon and planets. It points toward Venus and Jupiter, the sky’s brightest planets. Both planets will sink into the glare of the setting sun in the weeks ahead.
from EarthSky http://ift.tt/1HE492a
Tonight – the 46th anniversary of the first human footsteps on the moon – let the waxing crescent moon in the west after sunset teach you some things about skywatching. A useful concept for beginning skywatchers is that of the ecliptic – or path of the sun, moon and planets across our sky. We all know the ecliptic because it’s the path the sun follows throughout the year. But if you can visualize the ecliptic at night, it can help you find planets! Tonight – July 20, 2015 – notice that the illuminated part of the waxing crescent moon points into the ecliptic pathway, and it points toward the planets Venus and Jupiter.
On a waxing moon, the illuminated portion of the moon always points westward – toward the direction of sunset.
Because Venus and Jupiter lie to the west of tonight’s moon, the illuminated part of the lunar crescent points in the direction of these dazzling planets. As evening twilight starts to darken the sky, look for Venus and Jupiter below the moon and rather close to the horizon. Be sure to seek these brilliant worlds at dusk and nightfall, because they’ll follow the sun beneath the horizon by early evening.
If you have binoculars, you might also spot the star Regulus in the vicinity of these dazzling planets.
In the chart below, we expand the view of the July 20 sky to include Spica, the brightest star in the constellation Virgo the Maiden. The dark side of the waxing crescent moon always points eastward, in the moon’s direction of travel relative to the backdrop stars (and planets).
Look for the first quarter moon to pair up with Spica on July 23.
For illustrative purposes, the moon appears larger than it does in the actual sky. The green line depicts the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac. Regulus is the brightest star in the constellation Leo the Lion, and Spica is the brightest in the constellation Virgo the Maiden.
Both Venus and Jupiter are sinking closer to the glare of sunset throughout July, 2015. In fact, Venus and Jupiter will pass out of the evening sky and into the morning sky this August. If you’re an early riser, you’ll probably see Venus glorifying the eastern dawn by late August. You’ll likely spot Jupiter in the eastern morning twilight sometime in September.
Venus and Jupiter will adorn in the morning sky for the rest of 2015, and they’ll rendezvous for a beautiful conjunction in the predawn and dawn sky on October 26, 2015. Circle that date on your calendar!
Venus and Jupiter are the third-brightest and fourth-brightest celestial luminaries, respectively, after the sun and moon.
To cap things off on the night of July 20, see if the moon’s dark side is still aglow in earthshine – sunlight twice-reflected from Earth to the moon, and then the moon back to Earth. The earthshine may be easier to see through binoculars than the unaided eye.
Bottom line: On the evening of July 20, 2015, the illuminated portion of the waxing crescent moon point into the pathway of the ecliptic, or path of the sun, moon and planets. It points toward Venus and Jupiter, the sky’s brightest planets. Both planets will sink into the glare of the setting sun in the weeks ahead.
from EarthSky http://ift.tt/1HE492a
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