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Showing posts with label opposition. Show all posts
Showing posts with label opposition. Show all posts

Wednesday, July 1, 2020

What's In The Sky - July 2020

Get ready for summer stargazing! With the weather warming up, July is a great time of year to enjoy relaxing evenings under starry skies with your telescope or astronomy binoculars. Here are a few of Orion Telescopes and Binoculars picks for July stargazing...

Gas Giants at Opposition

Jupiter and Saturn both reach opposition one week apart this year, making July the perfect opportunity for planetary viewing! Opposition is when the Earth passes directly between a planet and the Sun. This coincides with the planets closest approach to Earth, providing an excellent opportunity for great views in a telescope. Both planets are easy to find in the Southern sky, about 7 degrees apart from each other. Jupiter reaches opposition on July 14th and Saturn about a week later on the 20th. During opposition, Saturn’s rings will be inclined at 21 degrees towards Earth, close to their maximum angle of 27 degrees. Combined with the planet's close approach to Earth, this makes July an excellent time to observe Saturn and its rings!

Jupiter imaged on 12/07/2012 with an Orion 180mm Maksutov-Cassegrain Telescope Optical Tube. Imaged by Cherdphong V. from Bangkok, Thailand.
Jupiter imaged on 12/07/2012 with an Orion 180mm Maksutov-Cassegrain Telescope Optical Tube. Imaged by Cherdphong V. from Bangkok, Thailand.

Grab a high magnification eyepiece or a Barlow lens, and check out the gas giants during opposition!

New Moon

July 20th is the darkest night of the month and therefore the best time to observe the more faint objects like galaxies and star clusters. Grab your observing gear and enjoy!

Hercules almost directly overhead and Scorpius

With constellation Hercules almost directly overhead and Scorpius to the south, there's plenty to see in July skies as summer continues. Check out globular star clusters M13 and M92 in Hercules, and explore Scorpius to find numerous deep-sky objects including open clusters M6 and M7, and globular clusters M4 and M80.

The Summer Milky Way

From a dark sky location in mid-July, the glorious Summer Milky Way shines as a band of light that stretches from the southern horizon to nearly overhead. As the night progresses, the Milky Way will arch across the entire sky. From a dark observing site, scan the Milky Way with 50mm or larger binoculars or a wide-angle telescope to explore some of the hundreds of open star clusters, emission nebulae and planetary nebulae that lurk among the star clouds.

Orion SkyQuest XT8 Classic Dobsonian Telescope Kit.
Orion SkyQuest XT8 Classic Dobsonian Telescope Kit.

July Challenge Object — Hercules Galaxy Cluster

About half a billion light-years from Earth in the constellation Hercules, not far from the star Beta Hercules in the southwest corner of the "keystone" asterism, lies the "Hercules Galaxy Cluster." This association is a group of 200-300 distant galaxies, the brightest of which is NGC 6050 at about 10th magnitude and can be seen with an 8" reflector like the Orion SkyQuest XT8 Classic Dobsonian under very dark skies with good seeing conditions. A larger aperture, 14"-16" telescope like the Orion SkyQuest XX14g GoTo Truss Dobsonian will begin to show about a half-dozen or more galaxies in one field-of-view. How many can you see in your telescope?

Orion SkyQuest XX14g GoTo Truss Tube Dobsonian Telescope.
Orion SkyQuest XX14g GoTo Truss Tube Dobsonian Telescope.

All objects described above can easily be seen with the suggested equipment from a dark sky site, a viewing location some distance away from city lights where light pollution and when bright moonlight does not overpower the stars.
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Monday, July 1, 2019

What's In The Sky - July 2019

Get ready for summer stargazing! With the weather warming up, July is a great time of year to enjoy relaxing evenings under starry skies with your telescope or astronomy binoculars. Here are a few of Orion Telescopes and Binoculars' top picks for July stargazing:

Saturn at Opposition

Saturn will shine brightly for most of July and reaches opposition on July 9th. The opposition is when the Earth passes directly between Saturn and the Sun. Since Saturn will be directly opposite the Sun in the sky as seen from Earth, the ringed planet will rise at sunset and set at sunrise, providing an excellent opportunity for great views through a telescope.

Saturn imaged at MasCot Observatory in 2003 with an 11" f/10 Celestron Schmidt-Cassegrain Telescope (C11) and a NexImage Solar System Imager. - Image by Michael Petrasko and Harry Hammond.
Saturn was imaged at MasCot Observatory in 2003 with an 11" f/10 Celestron Schmidt-Cassegrain Telescope (C11) and a NexImage Solar System Imager. - Image by Michael Petrasko and Harry Hammond.

Saturn also makes a close approach to the Moon on July 16th and should be close enough to fit both bodies in the field of view of most telescopes.

During opposition, Saturn’s rings will be inclined at 24 degrees to us, close to their maximum angle of 27 degrees. Combined with the planet's close approach to Earth, this makes July an excellent time to observe Saturn and its rings!

New Moon

July 2nd is the darkest night of the month and therefore the best time to observe the more faint objects like galaxies and star clusters. Grab your observing gear and enjoy!

Hercules is almost directly overhead and Scorpius

M13 - The Great Hercules Globular Star Cluster - Imaged on ATEO-1 by Insight Observatory.
M13 - The Great Hercules Globular Star Cluster - Imaged on ATEO-1 by Insight Observatory.

With the constellation Hercules almost directly overhead and Scorpius to the south, there's plenty to see in July skies as summer continues. Check out globular star clusters M13 and M92 in Hercules, and explore Scorpius to find numerous deep-sky objects including open clusters M6 and M7, and globular clusters M4 and M80.

Late July Meteors

July winds down with the Delta Aquarids meteor shower. For the best chance to see meteors, look towards Aquarius after midnight on July 29th into the early morning hours of July 29th. The Delta Aquarids is an average shower that can produce up to 20 meteors per hour. A 27-day-old moon should present minimal light interference to enjoy the meteors!

The Summer Milky Way

From a dark sky location in mid-July, the glorious Summer Milky Way shines as a band of light that stretches from the southern horizon to nearly overhead. As the night progresses, the Milky Way will arch across the entire sky. From a dark observing site, scan the Milky Way with 50mm or larger binoculars or a wide-angle telescope to explore some of the hundreds of open star clusters, emission nebulae, and planetary nebulae that lurk among the star clouds.

July Challenge Object — Hercules Galaxy Cluster

About half a billion light-years from Earth in the constellation Hercules, not far from the star Beta Hercules in the southwest corner of the "keystone" asterism, lies the "Hercules Galaxy Cluster." This association is a group of 200-300 distant galaxies, the brightest of which is NGC 6050 at about 10th magnitude and can be seen with an 8" reflector like the Orion SkyQuest XT8 Classic Dobsonian under very dark skies with good seeing conditions. A larger aperture, 14"-16" telescope like the Orion SkyQuest XX14g GoTo Truss Dobsonian will begin to show about a half-dozen or more galaxies in one field of view. How many can you see in your telescope?

All objects described above can easily be seen with the suggested equipment from a dark sky site, a viewing location some distance away from city lights where light pollution and when bright moonlight does not overpower the stars.
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Wednesday, July 18, 2018

2018 Mars Opposition

Like all the planets in our solar system, Earth and Mars orbit the sun. But Earth is closer to the sun and therefore races along its orbit more quickly. Earth makes two trips around the sun in about the same amount of time that Mars takes to make one trip. So sometimes the two planets are on opposite sides of the sun, very far apart, and other times, Earth catches up with its neighbor and passes relatively close to it.

During opposition, Mars and the sun are on directly opposite sides of Earth. From our perspective on our spinning world, Mars rises in the east just as the sun sets in the west. Then, after staying up in the sky the entire night, Mars sets in the west just as the sun rises in the east. Since Mars and the Sun appear on opposite sides of the sky, we say that Mars is in "opposition." If Earth and Mars followed perfectly circular orbits, the opposition would be as close as the two planets could get.

Artist's concept of Mars Opposition on December 24, 2007. The distances between the sun, the planets, and the distant nebula are not to scale. Image credit: NASA.
Artist's concept of Mars Opposition on December 24, 2007. The distances between the sun, the planets, and the distant nebula are not to scale. Image credit: NASA.

Of course, nothing about motion in space is quite that simple! Our orbits are actually elliptical (oval-shaped), and we travel a little closer to the sun at one end of our orbits than at the other end.

Mars oppositions happen about every 26 months. Every 15 or 17 years, opposition occurs within a few weeks of Mars' perihelion (the point in its orbit when it is closest to the sun). This year, Mars opposition occurs on July 27, 2018.

An opposition can occur anywhere along Mars' orbit. When it happens while the red planet is closest to the sun (called "perihelic opposition"), Mars is particularly close to Earth. If Earth and Mars both had perfectly stable orbits, then each perihelic opposition would bring the two planets as close as they could be. That's almost the way it is.

NASA's Hubble Space Telescope captured this striking image of Mars during the 2016 opposition and an illustration of the relative 'tilt' in the orbits of Earth and Mars. Image credits: NASA.
NASA's Hubble Space Telescope captured this striking image of Mars during the 2016 opposition and an illustration of the relative 'tilt' in the orbits of Earth and Mars. Image credits: NASA.

But once again, nature throws in a few complications. Gravitational tugging by the other planets constantly changes the shape of our orbits a little bit. Giant Jupiter especially influences the orbit of Mars. Also, the orbits of Earth and Mars don't lie in quite the same plane. The paths the planets take around the sun are slightly tilted with respect to each other.

So, with all these added factors, some perihelic oppositions bring us closer together than others. The 2003 opposition was the closest approach in almost 60,000 years!

Mars's orbit is more elliptical than Earth's, so the difference between perihelion and aphelion is greater. Over the past centuries, Mars' orbit has been getting more and more elongated, carrying the planet even nearer to the sun at perihelion and even farther away at aphelion. So future perihelic oppositions will bring Earth and Mars even closer. But we'll still have bragging rights for a while. Our 2003 record will stand until August 28, 2287!

Article Source: Mars in Our Night Sky - Mars Opposition
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