11th June 2006 --- During the June 3^rd public star party at the Griffith Observatory satellite, the seeing was bad due to the triple digit temperatures during the day, and the subsequent cool down at night to the 70s. Other than this the skies were pretty good: no clouds, very little haze, and practically no wind.

As night fell, there were four planetary targets up in the sky, but as would soon become apparent, only two of them were worth looking at, due to the bad seeing caused by the rising heat currents.

Mars is now, for all practical purposes, gone. It presents a disk that is less than 5 arc-seconds wide, and its low position near the horizon makes the view too degraded to see any features, even when one uses imaging equipment. Saturn was only a little higher, and suffered from the heat currents running off the asphalt parking lot. I didn’t try and image either one. The Moon was the highest target, and had the advantage that it was large enough that it presented good views at relatively low magnifications that mitigated the effects of the heat currents to some degree, but high powers here were out of the question.

That left Jupiter as the main attraction that night. Fortunately it rose above a set of tall trees. Plants in general give off less heat than concrete or asphalt as things cool down at night, and therefore the seeing above them is better. I got reports that the two temperate zone belts were visible, as well as the Great Red Spot, and some dark features in the normally white equatorial zone.  However, a few observers asked if I knew where the fourth moon of Jupiter was. No evidence of it existed in the raw video images I collected, so it was with some astonishment that, after stacking several hundred images and examining the results, I saw the black spot of a moon shadow clearly on all the processed images!  After checking with my planetarium program, I soon identified the spot as the shadow of Europa, which was transiting the disk of Jupiter during the time of the star party. In fact, it was preparing to exit off the disk when we all had to stop and pack away our equipment. It shows how bad the seeing was that night; I received no reports from anyone that they spotted the shadow, but then both Io and Europa cast small shadows, and it’s easy to miss them if the seeing is bad.

Another feature everyone was trying to see was Red Spot Jr., the companion to the Great Red Spot that has an interesting history behind it. Prior to 1998 or so junior was actually three or more white spots, two of which had been in existence and tracked by amateurs for 90 years, and the third having been tracked since 1939. Over a span of three years the storms collided and combined to form a white spot about half the size of the Great Red. Then since about the beginning of 2006, the spot quickly got pinker, until its color rivaled the Great Red’s. Unfortunately, I had misjudged the position, thinking it was still in the position relative to the Great Red as it appeared in a Hubble image from April, but it had actually moved closer to the Great Red until it was practically right underneath it. I found it in my stacked images once I corrected for my position error.

I took video of Jupiter from around 8:40 pm to 9:45 pm. The first image is the result from stacking the images from one of the first videos.  It shows Europa’s shadow, Red Jr., and the Great Red Spot, as well as the tremendous amount of activity in the equatorial region. This image is at the same scale as the raw videos used to generate them, but with far more clarity of detail and contrast.  The second image was generated from video taken towards the end of the evening. It has been re-sampled to twice the original’s size to help discern details.  It is annotated to identify some of the features. Both images are rotated to have north at the top and are non-mirror image, and were the result of stacking several hundred images from video files, then processing through wavelet filters. The camera was operating at the focus point of a 127 mm Maksutov with an equivalent focal ratio of f/25 or so. Compare the colors for The Great Red and Red Jr. Europa is visible in the second image as a thin crescent at the edge of Jupiter’s disk. It is easier to perceive such white objects when they reach the limb of Jupiter due to the phenomenon called limb darkening. Also, an examination of two images taken at slightly different times shows a thin crescent at the correct position to be Europa, so it is unlikely to be an artifact of image processing, although it might still be a atmospheric feature. Notice the large number of dark features in the equatorial region. Normally this region is mostly white with some festoons crisscrossing it, but all throughout that night I wondered at the many features visible in that region even in the raw images. The stacked and processed images show everything much clearer and more distinctly of course.

The Moon was fine for imaging if the magnifications were kept low. This image is the result of stacking several hundred images from a video, with the camera at the prime focus of my 127 mm f/12.1 Maksutov. It has been rotated with north at the top and is non-mirror imaged. The main feature in the center of the image is Mare Nectaris. A possible remnant of an outer rim for this feature is visible in the lower left portion of the image. The small crater with the V-shaped ray system leading away to the north is not Messier A/B, but the crater Rosse.  Note that Rosse and two other craters running south by southwest to north by northeast are lined up, are slightly elongated, and at least one other has a V-shaped ray system that lines up with Rosse’s.  This implies that they are part of a sequence of bodies impacting along similar trajectories on the lunar surface, and they may be either ejecta material from a large impact in the opposite direction from the V-shaped rays, or an event similar to comet Shoemaker-Levy impacting on Jupiter, the product of a comet breakup where the fragments are all traveling on similar paths through space.