JUPITER TODAY is a daily blog about the dynamic Jupiter system for the purpose of monitoring activity.
As Jupiter moves towards Superior Conjunction on 26 August 2015, it gets more and more difficult to view and monitor.
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. The blue line is the line of sight to Earth, while the gray line 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 near western elongation moving into quadrant 4 heading east. Europa is also in quad 4 heading east. As you can see from the orbit plot above, Io and Europa appear near each other from our POV most of the day today. Ganymede starts the day in quad 3 moving west. Callisto will spend all day in quad 4 heading east towards Jupiter.
At 6h UTC, Io and Europa are now firmly in quad 4 moving east. Ganymede is near its western elongation.
By 12h UTC, Io and Europa are both moving behind Jupiter. Ganymede has passed its western elongation and is now in quad 4 heading east.
At 18h UTC, Io and Europa have successfully moved behind Jupiter and are now in quad 1 moving east.
By 0h UTC tomorrow, Io has just gone thought its eastern elongation and is now in quad 2 moving west. Europa is still in quad 1 moving east. Ganymede and Callisto are in quad 4 moving east.
At 12:48 UTC, Europa is at apojove at a distance of 677,662.8 km. Io is at perijove at 13:04 UTC at a distance of 420,038.5 km.
At 09:02 UTC, Europa moves behind Jupiter. 96 minutes later, at 10:38 UTC, Io moves behind Jupiter. At 12:46 UTC, Europa reappears from behind Jupiter's shadow, and 32 minutes later (at 13:18 UTC) Io reappears from behind Jupiter's shadow. You can see that Io is catching up to Europa as it orbits Jupiter faster than Europa.
From 01:03 to 01:13 UTC, Io occults Europa. This is a 10.2 minute event with an impact parameter of 0.278 arc seconds. This means that the centers of the two bodies are 0.278 arc seconds apart. The smaller this number, the more total the occultation. Europa and Io are 75.6 arc seconds from Jupiter at the time of this event, which is a great distance for viewing. From 01:53 to 02:06 UTC, Io eclipses Europa. This is a 12.5 minute event with an impact parameter of 0.370 arc seconds. A nice eclipse. Then when Io and Europa have moves behind Jupiter, Io once again eclipses Europa from 15:18 to 15:56 UTC. This is a nice long 38.9 minute event with an impact parameter of 0.707. So not a very deep eclipse but still worth viewing and measuring if possible.
Here are the orbital ribbons for today:
At 0h UTC today, Jupiter has an RA of 10h 01m 0.3s, and a DEC of +13d 03m 14.5s. The phase angle today is 3.445 degrees, which is 0.134 degrees less than what it was yesterday. The angular separation between Jupiter and the Sun as seen from Earth is 18.582 degrees, which is 0.744 degrees less than what it was yesterday. The distance between Jupiter and the Sub is 805,129,106km, which is 37,680km further away than yesterday. This gives a radial velocity between Jupiter and the Sun of 1,570 km/h, which is 4.167 km/h slower than what it was yesterday. The distance between Jupiter and the Earth today is 947,585,803 km, which is 775,650 km further away than yesterday. This gives a radial velocity between Jupiter and Earth of 32,318.75 km/h, which is 1,208.625 km/h slower than what it was yesterday.
Intense motion all the time. Can you feel it?
Even though Jupiter is near Superior Conjunction (taking place on 26 August 2015), please send me your pictures of Jupiter! If you do, I'll post them to this blog! Please also include the time (in UTC if possible) you took the image, the telescope you used, the camera you used, and any other information you might think is useful.
Spread the word about this daily blog! This blog is subject to evolution. What can I do to make this blog more interesting and more informative?
Please send me your feedback, comments, and questions to jupitertoday AT gmail DOT com.
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.
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