Mars at Opposition – 2018

Mars at Opposition   Friday July 27th Mars will reach a point in its orbit around the Sun where it is at opposition relative to the Earth. at opposition The Earth is between the Sun and Mars, or any of the outer planets. At opposition both the Earth and the planet at opposition will have near identical heliocentric longitude. The opposition of Mars sometimes happens around the time that Mars is at its respective perihelion, closest to the Sun. If opposition happens during or near when the Earth is at its respective aphelion, furthest from the Sun, (first few days of July) then Mars will appear larger relative to when these dates are further apart.

What is opposition?
orbital-positions   The outer planets reach opposition when the Earth has moved into a position with the Sun on one side and the outer planet on the other side. Because all planets orbit in the same direction (toward the east), and all follow orbits that are slightly more elliptical than circular, oppositions occur at regular intervals of about 12 months (except for Mars). Mars is considerably closer to Earth and is moving faster than the other outer planets, so it takes approximately 26 months for Earth to catch up with Mars for an opposition.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Pluto at 2018 Opposition

orbital-positions   Thursday July 12th the Dwarf Planet Pluto will be at opposition. All outer planets and other solar system objects that orbit the Sun beyond the orbit of the Earth have opposition. At that orbital position the Earth is between the Sun and the outer solar system object, much like the Sun-Earth-Moon arrangement for a full Moon. At opposition the outer solar system object rises at the local time for sunset and sets at the local time for sunrise – again just like the full Moon.

   Where is Pluto and is Pluto visible to the naked eye? Pluto currently is a few degrees east from the handle of the teapot-shaped asterism for Sagittarius the Archer, and mid-way between Mars and Saturn. Pluto is visible, but with an apparent magnitude of 14.8 Pluto would only be visible with large aperture telescopes and with time-exposure pictures.

Click here to learn more about the New Horizons mission and take part in the mission with some of the interactives created by NASA.

   
   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Uranus at Opposition

view-from-uranus
   Thursday October 19th the outer planet Uranus reaches a position in its orbit around the Sun when it is on the opposite side of the Earth from the Sun. This coincidentally is known as opposition, and it is an orbital position which only the planets further from the Sun than the Earth may reach.

   At opposition the outer planet rises and sets in a fashion similar to our Moon when it is at full phase, in that the outer planet at opposition rises at sunset and sets at sunrise.

   On Thursday the outer planet Uranus will be several degrees from an even more outer planet, Dwarf Planet Eris. Both rise during the evening hours and are over the southwestern horizon before sunrise.

   
   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Neptune at Opposition – 2017

   Tuesday September 5th the outer planet Neptune reaches a position in its orbit around the Sun when it is on the opposite side of the Earth from the Sun. This coincidentally is known as opposition, and it is an orbital position which only the planets further from the Sun than the Earth may reach.
   At opposition an object orbiting the Sun beyond Earth’s orbit rises and sets in a fashion similar to our Moon when it is at full phase, in that the object at opposition rises at sunset and sets at sunrise.


Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Asteroid 3 Juno at Opposition

   Sunday July 2nd asteroid 3 Juno will be at opposition, that is, it will be 180o from the Sun with the Earth between the two. At opposition, any Sun orbiting object beyond Earth rises at about local time for sunset and sets at local time for sunrise. At about 9th-10th magnitude the asteroid will be too faint to be seen with binoculars or the naked eye.

   There are, however, a couple brighter objects sort of surrounding 3 Juno including Asteroid Hebe at 4th magnitude, and the outer planet Saturn at nearly 0 magnitude.
   Asteroid 3 Juno was the third asteroid discovered, hence its numerical prefaced name. It was discovered by German astronomer Karl L. Harding in 1804, and it is the 11th largest asteroid.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Saturn at 2017 Opposition

saturn-opposition-ani
   Thursday June 15th the outer planet Saturn reaches its orbital position known as opposition. This is a position which has the faster moving Earth passing Saturn and at opposition is centered between the outer planet and the Sun. Picture the arrangement with the Moon at full phase; Sun – Earth – Moon, and that is similar to the arrangement for Saturn at opposition.

   When an outer planet, like Saturn, reaches opposition that planet rises around local time for sunset and is visible all night.

   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Uranus at Opposition

view-from-uranus
   Saturday October 15th the outer planet Uranus reaches a position in its orbit around the Sun when it is on the oppisite side of the Earth from the Sun. This coincidentally is known as opposition, and it is an orbital position which only the planets further from the Sun than the Earth may reach.

   At opposition the outer planet rises and sets in a fashion similar to our Moon when it is at full phase, in that the outer planet at opposition rises at sunset and sets at sunrise.

   On Saturday the near full Moon will be within a few degrees from Uranus.

   
   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.