Jupiter Today | 18 August 2015 | Ganymede Hides

Hello!

JUPITER TODAY is a daily blog about the dynamic Jupiter system for the purpose of monitoring activity.

We start with the overall view of activity with the Jupiter system, showing the orbits of the four Galilean moons:

This is a view of the Jupiter system looking down on it.  Following the blue line to the left is the line of sight to Earth, while following the gray line to the left is the line of sight to the Sun.  The orbits of the four Galilean moons are shown.  The large dots indicate the position of each moon at 0h, 6h, 12h, 18h, and 24h (0h the next day) UTC for this date.  From this point of view, the moons revolve around Jupiter in a counter-clockwise motion.  For more information about this graphic, see the post from 30 July 2015.

At 0h UTC, Io begins the day at western elongation and will be in quad 4 moving east.  Europa is in quad 2 heading west.  Ganymede starts the day in quad 4 moving east towards Jupiter.  Callisto spends all day in quad 4 heading east.

By 6h UTC, Io is firmly in quad 4 moving east.  Europa is still in quad 2, but will be transiting Jupiter soon.

At 12h UTC, Io has moved behind Jupiter and Europa has transited Jupiter.  Ganymede is now moving behind Jupiter as well and is moving into quad 1 heading east.

By 18h UTC, Io is coming up on its eastern elongation.  Europa is now firmly in quad 3 heading west the rest of the day.  Ganymede has successfully moved behind Jupiter.

At 0h UTC tomorrow, Io has passed its eastern elongation and is now in quad 2 moving west.  Europa is firmly in quad 3 moving west.  Ganymede is moving east in quad 1.  Callisto continues in quad 4 moving east.

At 06:04 UTC, Ganymede goes through an apojove at a distance of 1,071,880.7 km.  At 09:49 UTC, Io goes through a perijove at a distance of 420,036.7 km.  At 09:53 UTC, Europa goes through its perijove at a distance of 664,495.5 km.

At 0h UTC, the position of Jupiter on Earth's celestial sphere is RA 10h 14m 11.3s, DEC +11d 51m 24.0s.  The phase angle today is 1.258 degrees, which is 0.138 degrees less than yesterday.  The angular separation between Jupiter and the Sun as seen from Earth is 6.708 degrees, which is 0.739 degrees less than yesterday.  The distance between Jupiter and the Sun is 805,726,046 km, which is 36,837 km greater than yesterday.  Jupiter appears to be moving away from the Sun at a velocity of 1,534.875 km/h, which is 0.792 km/h faster than yesterday.  The distance between Jupiter and Earth is 955,947,219 km, which is 294,091 km further apart than yesterday.  Jupiter and Earth appear to be moving apart at a velocity of 12,253.792 km/h, which is 1,283.625 km/h slower than yesterday.

At 09:09 UTC, Io moves behind Jupiter.  From 09:26 to 12:18, Europa transits Jupiter.  From 09:43 to 12:34, the shadow of Europa transits Jupiter.  At 10:18 UTC, Ganymede moves behind Jupiter.  At 11:34 UTC, Io reappears from Jupiter's shadow.  At 14:29 UTC, Ganymede reappears from Jupiter's shadow.

There are no satellite mutual events today.

Now for the glorious Orbital Ribbons:

I also continue to enjoy the spectacle of Superior Conjunction, visible now with the SOHO spacecraft:

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Please send me your feedback, comments, and questions to jupitertoday AT gmail DOT com or the comments section of this blog.

With my gratitude, the data used to create the orbit plots and ribbons was supplied by the JPL Horizons website.  The graphics showing the location of the four moons as seen from Earth are via 'Jupiter Viewer 2.8'.  Jupiter-Satellite and Satellite mutual events data is supplied from IMCEE.

Until tomorrow, I bid you Peace.