Jun 142017

For the last couple of weeks the weather has not been cooperating with the PTO’s support of NASA’s Juno mission. The last two nights were clearer but the atmosphere was very turbulent. My Friday night session did not get any useful images and out of all last night’s imagery I was able to get just one.

The bright spot just to the right of Jupiter is the moon Io. The other spot, a dark one, is near the bottom center of Jupiter. I originally thought is was atmospheric but a quick check with several planetarium programs revealed that the Jovian moon Ganymede is right there. It’s not Ganymede’s shadow as that wouldn’t cross Jupiter for another 4 hours.
My main scope is a Newtonian reflector which inverts the image, so South is at the top which conveniently matches the illustration below. Sky & Telescope magazine graciously gave me permission to use their Jupiter belt/zone illustration so I don’t have to try to make my own. Belts are the dark bands – zones are the light ones. As you can see, the spot (Ganymede?) is right on the southern border of the North polar region.

Almost any kind of Jupiter observation requires familiarity with the correct names for the various belts and zones. Here south is up; in an inverting telescope such as a Newtonian reflector, or a refractor, Schmidt-Cassegrain, or Maksutov used without a star diagonal, north will be down and east to the right. Telescopes used with a star diagonal will have north up but east and west reversed. The planet’s rotation causes features to move from east (following) to west (preceding). (c) 2015 Sky & Telescope. Used with permission.

For more Jupiter information see the original Sky & Telescope article:

 Posted by at 16:22
May 262017

The PTO is still configured for planetary imaging in support of NASA’s JunoCam project. The air was not very steady last night which shows as the focus shifts in and out during the animation. However, this was the first time I have been able to follow one of the moons as it crosses the planet. The first moon visible is Europa, and it remains visible as it starts to cross in front of Jupiter. The second moon that comes in from the left is Io. Io was going to cast a shadow on Jupiter, unfortunately the planet became obscured by my western tree line before it happened.

There is a 19 minute jump in the animation. My capture software hung saving one of the videos and I had to stop and restart the application. Most of the delay was me not noticing the situation.

 Posted by at 13:39
May 152017

The Jupiter session on May 13 went long enough that I decided to stick around a little longer and see how Saturn was looking. Saturn is 17° lower on the southern horizon than Jupiter. That puts it right in the light dome from Eglin AFB and, on the 13th, only 34° high. The atmosphere wasn’t too bad and the resulting images were acceptable.

 Posted by at 21:55
May 112017

Last night was again clear enough to get some Jupiter footage. However, there were some high clouds that interfered. Luckily, Jupiter was outside of the ice crystal halo surrounding the full Moon which would have significantly reduced the contrast in the images.

Jupiter is just barely visible tucked right up against the western tree line.

Jupiter with this good a focus shows how steady the atmosphere was.

The Jovian moon visible in this video is Io, the innermost of the four Galilean moons. It orbits Jupiter in only 42.5 hours and is the most volcanic body in the solar system.

According to mythology Io was one of the god Jupiter’s mortal romantic conquests. In fact, quite a few of the named moons are named for Jupiter’s human entanglements.

 Posted by at 22:21
May 102017

Wednesday night was a short one due to work the next morning. There was no Great Red Spot (GRS) visible but I was able to get some acceptable imagery that included 3 of Jupiter’s large moons. They are quite blurred due to their quick motion and our atmosphere, but they are definitely visible.

The moon visible on the right of Jupiter is the moon Europa. It disappears behind the planet. The second moon is Ganymede. It appears to the lower left of the planet as it emerges from Jupiter’s shadow. The third moon shows up from the upper left towards the end of the video. That moon is Callisto.

 Posted by at 21:57