Category Archives: Saturn

Juno at Jupiter-Update

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   The Juno Spacecraft is now fully engaged in making its planned orbits around the outer planet Jupiter. Since arriving and orbital insertion the spacecraft has made 6 orbits around Jupiter sending back amazing images and advancing our knowledge of the planet and its role in the solar system.
   Showing my age but I can remember how excited I was during the Voyager 1 and 2 flybys of the outer planets Jupiter, Saturn, Uranus, and Neptune during the 1980s. It was 40 years ago, Voyager 1 September 5th1977 – Voyager 2 August 20th 1977, when the spacecraft were launched. While both were targeted for a Jupiter and Saturn flyby Voyager 2 eventually had its mission rearranged so that it would fly past all four of the outer giant planets in a mission called the ‘Grand Slam’ or ‘Grand Tour’. The images from those flybys were just as exciting as the images we see from the current Juno mission albeit improved after 40 years of imaging technology advances.
   So Where are the two Voyagers now? Click here to find out.
   Click here to go to the NASA Video web site to see a short video (15 minutes) about the Voyager mission to the outer planets. This is part of a video series I often used in my Planetarium and classroom during the 1990s – so please realize that the graphics and animations, as well as some descriptions and some explanations are not necessarily as ‘advanced’ as things are now. However two of my heroes, Dr. Edward Stone, and Dr. Andrew Ingersoll, are featured making comments about some of the Science and discoveries.
   Below is a well done video compilation of images taken by the Juno Spacecraft. Click here to go to the Vimeo web site for the original video.

   
   
   

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.

August Moon at Apogee

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   Our Moon reaches apogee, (greatest distance from Earth), on Wednesday August 2nd. At that time the Moon will more or less be at a distance of 31.75 Earth diameters (405,934 km or 252,857 miles) from the Earth.
   On the day of the apogee Moon the 11-day old waxing gibbous phase, rises mid-afternoon and is about 3o from Saturn and around 14-15o degrees from the reddish star Antares in Scorpius the Scorpion. The Moon and Saturn will fit easily within the field of view binoculars.
   Does our Moon actually go around the Earth as the above 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*

*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 go to bobs-spaces.

Moon Passes Antares and Saturn

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   Welcome to August!
   Over the next few days the Moon will wax from first quarter on Sunday July 30th into its waxing gibbous phases prior to reaching full Moon on August 7th. During this time, Tuesday August 1st to Thursday August 3rd, the Moon will first pass the reddish star Antares in Scorpius the Scorpion then the next day pass the outer planet Saturn on the 2nd. The following day has the Moon about mid-way across the Milky Way as the picture shows, however given the Moon’s bright reflected light it would be nearly impossible to see the Milky Way.
                           Click on a graphic below to see it larger               

   
   
   

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.

It’s The Final Countdown or Cassini Spacecraft’s Grand Finale

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   Two months from this posting, September 15th, the Cassini spacecraft will end its mission at the planet Saturn by diving into the planet’s atmosphere and self destruction.
   This animated graphic shows the hourly position of the Cassini spacecraft as it makes a distant flyby of two of Saturn’s smaller moons, Atlas and Janus on July 19th. (the moons and spacecraft have been greatly enlarged to make them visible)
20 Years Ago
   On October 14, 1997, NASA launched Cassini, its largest interplanetary spacecraft, on a nearly seven-year voyage to Saturn. The voyage to Saturn was a two-part mission that included an orbiter and the Huygens probe. The Cassini orbiter was designed to explore Saturn’s system as it looped over, under, and around the planet’s many moons and rings. The Huygens probe was designed and planned for a study of the atmosphere and surface of Saturn’s largest moon, Titan, as well as a parachute-assisted soft landing on the surface. On September 15th the exploration phase of the Cassini mission will end as the spacecraft runs out of fuel and descends into Saturn’s atmosphere. As frictional forces tear the spacecraft apart, instruments on-board will send back data about the planet’s atmosphere.
35 Years Ago
   Typically, little is known about what happens after or before the active part of a mission. We know that the follow-up to a mission is the data analysis, which usually takes many years. What is generally not acknowledged is the lead-up to the official mission, which begins with the launch. The Cassini Mission was first proposed in 1982, 15 years before the actual launch. Several years of planning and coordination between NASA and the European Space Agency followed. By the end of the 1980’s, the mission had been approved and was finally launched in 1997. Thirty-five years will have passed since the inception of the Cassini mission and the demise of the spacecraft when it enters Saturn’s atmosphere.

    Where is Cassini Now?
    Cassini grand finale fact sheet
    Cassini mission
    Cassini mission timeline poster
    Four Days at Saturn video
    Grand finale

   
   
   

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.

July Moon at Apogee

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   Our Moon reaches apogee, (greatest distance from Earth), on Thursday July 6th. At that time the Moon will more or less be at a distance of 31.82 Earth diameters (405,934 km or 252,235 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*

*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?”

   On the day of the apogee Moon the 13-day old nearly full Moon, but still in the waxing gibbous phase, rises around local time for sunset and is about 2o from Saturn and around 14-15o degrees from the reddish star Antares in Scorpius the Scorpion.

   
   
   

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.

Saturn at 2017 Opposition

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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

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   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.