Jupiter Today | 16 August 2015 | Jupiter Enters SOHO

Hello! Today Jupiter entered the field of view of the LASCO C3 camera on the SOHO spacecraft.  As it moves towards Superior Conjunction, Jupiter will also enter the LASCO C2 camera that will give us higher resolution.  I plan on taking photometry measurements every day during this event to see how the brightness of Jupiter varies.  Does anything happen to Jupiter, Earth, or the Sun at this time?

Here's the current LASCO C3 image, showing Jupiter appearing at left-center:

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 in quad 3 moving west.  Europa is in quad 4 moving east.  Ganymede is in quad 3 heading west.  Callisto spends one more day in quad 3 moving west.  I'm pretty sure that Callisto is becoming visible in the SOHO image above -- that little extension to the west of Jupiter.  We'll see over the course of the next day if this extension changes in any way to confirm.  Once Jupiter is in the C2 field of view, Callisto and maybe Ganymede will become visible at their eastern and/or western elongations.

By 6h UTC, Io is at its western elongation and is now in quad 4 moving east.

At 12h UTC, Io is firmly in quad 4 heading east, Europa is soon to move behind Jupiter and head into quad 1.

By 18h UTC, Io and Europa have moved behind Jupiter and are now both in quad 1 moving east.  Ganymede is at its western elongation and is now in quad 4 moving east.

At 0h UTC tomorrow, Io and Europa are firmly in quad 1 moving east.  Ganymede is now firmly in quad 4 heading east.  Callisto is near its western elongation and will be past that early tomorrow.

At 15:19 UTC, Europa goes through an apojove at a distance of 677,662.8 km.  At 15:32 UTC, Io goes through a perijove at a distance of 420,042.3 km.  Notice that Europa's apojove and Io's perijove are on the same side as Jupiter and both are in near-alignment with the Sun.

At 0h UTC, the position of Jupiter is RA 10h 12m 31.9s, DEC +12d 00m 34.0s.  The phase angle is 1.535 degrees, which is 0.138 degrees less than yesterday.  The angular separation between Jupiter and the Sun is 8.187 degrees, which is 0.741 degrees less than yesterday.  The distance between Jupiter and the Sun is 805,652,391 km, which is 36,956 km further away than yesterday.  Jupiter is radially moving away from the Sun along it's 11-ish year orbit at a velocity of 1,539.833 km/h, which is 4.042 km/h slower than yesterday.  The distance between the Earth and Jupiter is 955,328,230 km, which is 355,806 km further away than yesterday.  Earth and Jupiter are radially moving apart at a velocity of 14,825.25 km/h, which is 1,283.667 km/h slower than yesterday.

At 14:39 UTC, Io moves behind Jupiter.  Six minutes later -- at 14:45 UTC, Europa moves behind Jupiter.  At 17:06 UTC, Io appears from Jupiter's shadow.  At 18:00 UTC, Europa appears from Jupiter's shadow.

From 07:19 to 07:40, Io occults Europa.  This 21.1 minute event has an impact parameter of 0.272 arc seconds.  From 07:51 to 08:20 UTC, Io eclipses Europa.  This 28.9 minute event has an impact parameter of 0.116 arc seconds.

From 13:24 to 14:02 UTC, Io once again eclipses Europa.  This 38.2 minute event is almost a total eclipse with an impact parameter of 0.033 arc seconds.  An from 14:01 to 14:32 UTC, Io occults Europa in a 31.2 minute event with an impact parameter of 0.229.

What would be be like to view these events from Europa?  Use your imagination to transport yourself there and view it!

Or, we can cheat and use Stellarium, which simulates things pretty well.  The image below was created by Stellarium.  The view is from Europa looking towards the Sun and Earth (Venus is there, too) with the dark side of Jupiter dominating the center of the view (hard to see because it's so dark, but there if you look carefully):

So as you can see, this occultation takes place just before Io and Europa move behind Jupiter.

And now, the glorious Orbital Ribbons which represent the spacial and temporal connections between the four Galilean moons:

Jupiter is so near Superior Conjunction (taking place at 22:00 UTC on 26 August 2015) that photography and other data collection isn't practical.  We'll have to wait about a months after SC to start viewing the Jupiter system again.

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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.