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.

Moon / Saturn Conjunction and Jupiter Pauses Briefly

   Friday June 9th one of the outer planets, Jupiter, becomes stationary in its retrograde westward orbital motion around the Sun. It will now begin moving in direct motion, its orbital direction around the Sun toward the east – as we view it from the Earth. Jupiter’s retrograde motion is something that occurs to varying amounts as the Earth passes by each outer planet.
   This animated graphic is set to show the motion of Jupiter from early May through the end of June. At the start the graphic shows where Jupiter is relative to the star Spica, and then it zooms in to make the retrograde loop for Jupiter easier to see.
   The Earth passing by an outer planet is a result of the Earth having a faster orbital speed, and as the angles between Earth and an outer planet change there is the appearance of the outer planet slowing down and stopping its regular eastward motion. Then for a time ranging from a week or so to several months the outer planet appears to be moving backward or toward the west. After a time the planet resumes its eastward motion.

   On Friday the 9th the just past full Moon, a 15-day old waning gibbous Moon, will be rising about an hour after local time for sunset. Between 2-3o to the right, or west, from the Moon is the planet Saturn as this graphic shows.

   
   
   

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.

May Apogee Moon

   Our Moon reaches apogee, (greatest distance from Earth), on Friday May 12th. At that time the Moon will more or less be at a distance of 31.84 Earth diameters (406,210 km or 252,407 miles) from the Earth.
   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*


   The 16-day old waning gibbous Moon rises a few hours before midnight local time, and is located near the reddish star Antares in Scorpius the Scorpion, and the planet Saturn.

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”
   
   
   

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.

Mars – Saturn at Heliocentric Opposition


   Monday May 1st the planets Mars and Saturn will have reached a point in their respective orbits where they are on opposite sides of the Sun and are approximately 180o apart, or at what is called heliocentric opposition. Using the system of heliocentric longitude Mars has a heliocentric longitude of 83o while Saturn has a heliocentric longitude of 263o

   Mars is visible above the western horizon at around sunset local time near the two open star clusters of Taurus the Bull – the Pleiades and the Hyades. On the other side of the sky, over the eastern horizon is Saturn, rising around midnight local time.

   
   
   

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.

Moon Near Saturn


   Sunday morning, April 16th the 19-day old waning gibbous Moon will rise near the planet Saturn. The two will be within the 7o field of view of 10×50 binoculars and will be easily seen over the eastern to southeastern horizon in the hours before the sun rises.
   
   
   

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 Begins Retrograde Motion


   Thursday April 6th the outer planet Saturn begins its retrograde motion. This is an apparent motion that Saturn or any outer planet, dwarf planet,or asteroid has when compared to the faster moving Earth. The Earth, moving more quickly around the Sun than an outer object, will catch up and pass by the outer object sort of like a car passing a slower moving car.
   As the faster moving Earth passes by, the outer object appears to stop its eastward direct or prograde motion, and then moves westward, or retrograde, for a while until it again stops before resuming its prograde motion. Saturn will remain in retrograde until June and will travel westward out of Sagittarius the Archer into the boundaries of Ophiuchus the Healer.

   
   
   

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 and Some Messier Objects


   In the early morning hours before the Sun rises the summer (northern hemisphere) Milky Way arches across the sky from the southern horizon toward the northern horizon. Over the southern horizon is the constellation Sagittarius the Archer and the direction toward the center of the Milky Way Galaxy. In this direction is the planet Saturn and within the field of view of binoculars are several nebula, some of which are visible to the naked eye.
    Despite the use of optical aids like binoculars or telescopes we do not see the colors of these object that you may see in photographs. Regardless, this part of the sky is filled with many objects visible to the naked eye and certainly with binoculars. And assuming the local skies are relatively dark then viewing this area of the Milky Way will provide many viewing rewards.

   
   
   

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.