Jupiter at Eastern Quadrature

1apr-jupiter-east-quad   On Tuesday 1 April the position of the planet Jupiter with respect to the Earth and the Sun places the solar system’s largest planet at an orbital position called eastern quadrature. Jupiter is at a 90 degree angle from the Earth as this graphic shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Jupiter follows the Sun across the sky from east to west as the Earth is rotating, meaning that Jupiter rises after the Sun and consequently sets after the Sun.
   Where is Jupiter now? Click here to see a graphic showing Jupiter and the star field of northern hemisphere winter and spring stars. I purposely chose a later time, 11:30 pm CDT, because at about that time Saturn and Mars will be visible above the eastern horizon.

   This is a short 6-7 minute video I made as part of a live musical performance called “Orbit” that was performed at the Gottleib Planetarium in Kansas City Missouri in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Jupiter, Saturn and some of their moons as viewed from the Cassini spacecraft.

   
   
   
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.

Mars Opposes Neptune

mars-neptune-opp   And Uranus is at eastern quadrature. So what does that mean?
   Mars opposes Neptune in the sense that each planet is 180 degrees from the other and using their heliocentric coordinates Mars is at approximately 155o while Neptune is at approximately 334o. This is called heliocentric opposition as the two planets are on opposite sides of the Sun. When two planets are in heliocentric opposition and separetd by 180o one planet will be in the morning skies, Mars, while the other is in the evening skies, Neptune.

uranus-e.quad   The outer planet Uranus is at eastern quadrature today meaning that using the Earth, Sun, and Uranus the three form a right angle with Uranus 90o from the Earth and Sun. This places Uranus on the eastern side of the Earth as the Earth rotates. Whenever an outer planet is at or near eastern quadrature that planet or planets is to the east of the Sun and this places them in the evening or night skies.
   
   
   
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.

Saturn at East Quadrature

Click on this image for full size

Click on this image for full size

   Today the position of the planet Saturn with respect to the Earth and the Sun places this ringed planet at what is called eastern quadrature. Saturn is at a 90 degree angle from us as this graphic shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Saturn follows the Sun across the sky from east to west as the Earth is rotating, meaning that Saturn rises after the Sun and sets after the Sun.
   Where is Saturn now? Click here to see a graphic showing Saturn and some of the brighter stars over the southwest horizon at 10 pm CDT.

Learn a little (or a lot) more about Saturn by visiting the Cassini at Saturn mission web site.
Click here to go to the Cassini Mission web site.
Click here to go to the Cassini Mission Flyby web page to see when the next Saturn satellite flyby will be.

   This is a short 5 minute video I made as part of a live musical performance called “Orbit” that I was part of in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Saturn and some of its moons as viewed from the Cassini spacecraft that month.

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Uranus at East Quadrature

Uranus at East Quadrature

Uranus at East Quadrature


   Ok- as having once taught middle school grades 6 through 8 I have always enjoyed this part of the lessons about the solar system. That is, when I can explain to students about a debate over the pronunciation of this particular planet. Of course saying ‘Your Uh Nuss’ is not as humorous as the kids preferred ‘Your Anus’! I like to describe this debate (with tongue in cheek), that there are two sides to the pronunciation debate – sort of split down the middle if you will. Eventually we get to the planet and its characteristics. Eventually.
Uranus in the Evening Sky

Uranus in the Evening Sky

   So what about this East Quadrature? This is a position of an outer planet with respect to the location of the Earth and the Sun. Outer planets at eastern quadrature are located at a 90o angle from the Earth and the Sun as shown in the first graphic above. This is one of the three positions that are used to describe an outer planet location during the Earth’s orbit around the Sun — not the outer planet’s orbit. An outer planet will be at eastern quadrature, then approximately 3 months later at opposition (Uranus-Earth-Sun), 3 months later at western quadrature, 3 months later at superior conjunction (Earth-Sun-Uranus), then the pattern repeats.
Uranus in Motion

Uranus in Motion

   So where exactly is Uranus (the correct answer is not behind you!!)? This outer planet currently rises before sunset local time and is over the southern horizon as shown in the second graphic above. It is too dim to be seen with the naked eye, or at least right at the fringes of what we can see – so if your skies are really dark then you may be able to discern the faint glow of reflected sunlight from Uranus.
   With binoculars it will become, in a sense, one of the stars in your binocular field of view. In this simulated 7×50 binocular view Uranus is slightly brighter that the 6th magnitude stars nearby. To verify that you are actually viewing Uranus use this animated graphic as a star field guide. Wait a couple of weeks to allow the slower moving planet to move in its orbit. Then observe this same area to see if there have been any changes. This graphic starts with the Uranus near a pair of equal in brightness stars on 26 November. The graphic dissolves into showing the position of Neptune today, and then dissolves one last time to show where Uranus is with respect to the pair of stars.

   Here is a couple minute long clip from a video I produced that was used during a live music performance by the group Dark Matter under a 60-foot diameter planetarium dome.

   
   
   
Click here to go to the Qué tal in the Current Skies web site for more observing information.