Though not a sketch per se, I believe the following observations are appropriate for my sketchbook. Please consider them as my "notes", scribbled in the margin, for future reference.
This evening I decided to take the pressure and distraction that comes with sketching an object off and spend a relaxed hour or so with Jupiter, simply observing. Transparency was not all that good as we had some clouds move through earlier, plus the moon gave the sky a washed-out glow, but seeing was not so bad…somewhat better than usual in that I was able to focus more tightly on the Galilean moons and bring them into sharp (or at least sharper) points of light (does this make sense?).
My objective tonight was to just look at Jupiter and see if I could make out any of the finer details that others have sketched and that I seem to be missing through my 90mm.
I began my survey using a 25mm EP (x36). The N and S EQ belts were apparent, but not much else (usually I can see a hint of the N Polar region (NPR) at this magnification, but not tonight). The addition of a yellow filter offered little improvement; it did, however, cut down on some minor glare and allow for an even tighter focus. As such, I decided to use the filter in all EPs for the remainder of my viewing session.
In an earlier discussion, someone suggested that I use a 10mm EP (x91) to bring out more detail so I gave it a second try (ordinarily, my cut-off for planetary observing is 17mm due to resolution issues, but I'm still a rookie). At x91 magnification, the NPR became apparent; though I think what I am probably seeing is a blending of the NPR and the N n Temperate belt.
Additionally, the N Temperate belt showed up as a thin scratch of shading between the N Temperate zone and the N Tropical zone.
In my observation of 19 November 2012 I mentioned that I was able to catch a “hint” of the South Polar Region (SPR), but this feature was not visible tonight for some reason; however, by using averted vision, I believe that I was able to catch a glimpse of the South Temperate Belt (STB). This is an element that I hadn't noticed before.
From here, I experimented with even higher magnifications (8mm (x113) and 6mm (x151) w/ yellow filter) and though I lost further resolution, I am convinced that I am beginning to discern subtle variations of shading in the EQ belts. At this early stage these are nothing that I could accurately represent in a sketch (other than as arbitrarily placed “smudges” of darker or lighter gray within the belts). Since the EQ belts show up regardless of magnification, perhaps this is where I should focus most of my attention?
Although the southern portion of Jupiter appeared to me to be without detail for the duration of this session, I did have a couple of lucid moments where everything north of STB seemed to gel and form an image of what I know the planet looks like as a whole (sans the GRS, which was out of sight). My hope is that as my eye becomes better trained, these lucid moments become the norm.
One thing that was particularly “neat” about this extended view was that I was able to observe one of the moons, Io, approach the northern limb of the planet…and then just “disappear”.
Never seen it happen before tonight.
Now, THAT was cool!
Thanks for viewing...er, reading. Comments, criticism, and advice are always welcome.