Planetary Potpourri

August finally brought Jupiter and Mars above the tree line for me in the pre-dawn skies. The classic humid skies under a dome of high pressure that is typical of summer around here have the one advantage of often providing some steady skies. 

Saturn
Aug 1, 2024

The month kicked off with the final transit of Titan across the far southern Saturnian cloud-tops for the current apparition. From here on out the massive moon will skim across the south pole until our geometry brings it back across the planet again. Arising at 2 a.m., I was blessed with very fine seeing (9/10) and started with captures in WL with a UV/IR block, resulting in the color image shown above. The low albedo of Titan compared to the planet's clouds yielded a dusky silhouette of the moon just skimming across the SPR. On the planet there are multiple bands in the N. hemisphere while the S. hemisphere is a bit more homogeneous and bluer in appearance. The shadow of the rings on the globe is easily seen, as the globe reciprocates with its shadow on the rings. Some vague hints of Cassini's division are seen. While I did not discern it while doing the imaging run, upon processing I found that if you look closely, you can also make out the tiny shadow of Dione which was in transit at the same time, lying just preceding the CM and at the latitude of the southern edge of the SEB.

Switching to the R +IR filter yielded the greyscale image above as Titan started its egress from the planet's disk. Between the different wavelength and the limb darkening, Titan appears white rather than its dark silhouette earlier in WL when over the SPR. In this view the planet itself shows multiple bands and bright EZ. The banding striations in the Southern hemisphere are much easier to see in this wavelength compared to the WL, and while not obvious the Cassini division is also a tad easier to pick out. And as with the WL capture, you can catch Dione's shadow just past the CM and at the southern flank of the SEB.

Jupiter
Aug 23, 2024

Some above average seeing greeted me again on Friday morning the 23rd (seeing 8/10, transparency 7/10) for a Jupiter session. Started off with Great Red Spot near CM, followed by a very chaotic section of the SEB punctuated by a strong rift. Given that white clouds are higher in the atmosphere, it makes me speculate that perhaps this could be the beginning of an SEB fade? Time will tell. The images also allowed for a rough estimate of the GRS's size, which came out to roughly 13,100 km - a new low. For decades the boast has always been that you could fit 2-3 Earths inside the massive storm, but with our terrestrial diameter of 12,750 km it may soon come to pass that it won't be large enough for even a single Earth.

The South Temperate Belt, home to the long-enduring anti-cyclone "A" storms, was featuring 3 of them at this longitude. I believe from left to right we are looking at A4, A3, and A2. The North Temperate Belt also features a chronic storm, NN-WS-4, just trailing the GRS's latitude a bit.

The image also displayed some intense "hot spots" along the southern edge of the Northern Equatorial Belt, spawning blue festoons trailing down into the EZ. The NEB is now back to its dominant self, having extended northward to reclaim its girth. Along its northern edge we have some ovals. These appear to be the long enduring "White Spots" (such as WS-E, WS-Z) that have been surrounded by the expanding NEB, making them far more conspicuous than in recent years by the added contrast.

Mars
Aug 23, 2024

With power still remaining on the laptop after my Jove captures I swung over to Mars to see what was up. At just a little larger than 6", I am always amazed that the SPLICE process can pick up any features at all. Sinus Meridiani and a little of Sinus Sabaeus are seen as well as Margarifiter Sinus and M. Erythraeum. There is no sign of a South Polar Cap which has dissipated as winter retreats in the planet's Southern hemisphere. But the northern chill has begun as evidenced by a North Polar Hood beginning to form. Niliacus Lacus also can be seen extending out from under the hood. While this won't be a great apparition with Mars' size topping out at a little above 13" in January, it still promises to be fun imaging our mysterious neighbor.

With Saturn hitting opposition in a few days and Jupiter nearly at western quadrature, the 2025 planetary season is definitely upon us. Here's hoping for lots of opportunities to check in on them under clear and steady skies!