The following is a compendium of sketches from astro.geekjoy.com. For details as to date (and time) of a particular drawing simply right click on the image and view the image properties. (The information is part of the image filenaming protocol.) Text facing the image is the first paragraph (or so) of discussion from the associated observation report. A link shows the related report from astro.geekjoy or calls to a threaded discussion on AstroTalk. (AstroTalk is a members only forum requiring a password - registration is all that is needed to become a member.)
Like Mars - and unlike Luna, sketching the Gas Giants is a simple matter of drawing what you see. Jupiter - again like Mars, displays low contrast features which defy simple draftsmanship. Unlike Mars, Jupiter can occasionally display such a profusion of low level detail that the mind and hand boggle at the sight. Contrast this again with Saturn, a planet whose crisp views are more difficult to capture than one might expect - simply because of the complex geometries introduced by the ring system.
The coming viewing season (winter 2002 and 2003) should provide more opportunities to sketch both gas giants. However, seeing conditions and weather patterns are a variable that often waylay the best layed plans of observers and sketchers alike...
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This and the following sketch were done within an hour of each other under variable conditions from Backyard Boulder Creek. Seeing ranged from about 6-8/10. It was an educational experience to see micro detail in the two equatorial belts come and go with the variation. But there was ample time of good stability to see some fine detail - especially within the northern and southern equatorial belts.
Several days before these sketches, I had critically collimated Argo. This was necessary after getting a new diagonal. Due to its two inch size and architecture, this particular diagonal does a far better job of centering the planet in the field after rotation than the smaller unit had done when improving eyepiece observing position. As a result, Argo's best views of Jupiter and Saturn are now discernably superior to those of past years.
During the course of this sketch, my eye was often attracted to a lengthy region of contrasty turbulence along the southern frontier of the SEB west of the GRS.
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This sketch shows the GRS transiting the planets central meridian around 8:00pm PST on March 9, 2003. In use were the 15mm Ultrascopic and 1.8x shorty barlow for 215x magnification. During a sketch earlier in the evening (seen above), stability stayed closer to 8/10. I was able to employ a recently acquired 12.3mm ED2 with barlow for a nominal 260x. Attempts were also made to view the planet at 325x but conditions were not quite up to it. In particular the soft equatorial belt began to dissolve at the highest power.
Of particular interest in this sketch is the dark clot or barge trailing the GRS along the northern frontier of the NEB.
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Over the last few months I've become quite accustomed to catching one or more dark barges embedded in Jupiter's NEB. Well, for the first time, this very evening, the NEB was dominated more by white ovals than barges...
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No, not the best view of Jupe had through 150mm MCT Argo - but one illustrative of a phenomenon noticed on previous occasions. Take a look at the dark barge egressing (to west) on the North Equatorial Belt (NEB). This very obvious darkening appears to be paralleled by "echo darkenings" in the NTB and STB! Are these real? Or are they optical illusions? - Only Jupiter knows for sure. (Sketch made at the 210x eyepiece under natural light and through a 7/10 stability 5.0 ULM sky. - No report filed elsewhere)
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At left is the one and only sketch made at the eyepiece of F5 80mm achromat "The Pup". One reason? This was one of the few times when the optic tube assembly "hung" in such a way that "perfect" collimation was possible. (When you hang two barlows, mirror diagonal and 15mm eyepiece on the ST80's focuser, collimation suffers.) Another reason? Jupiter had just culminated under stupendous seeing stability. (Due to the Pup's imperfect optics, it maxes out at 8/10, the sky was probably a "9" this evening - something that Argo would have loved!) Magnification? 140x. You can see (from the sketch) that the NEB showed edge thickness irregularities. SEB was distinctly rifted. Two extra-equatorial belts were clearly discerned (NTB and STB). Most interestingly, there was a "hint" of the EB bisecting the equatorial zone. Yep, as good as it gets! (No report filed elsewhere)
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Under some very solid 8/10 stability conditions, caught Europa in transit this evening (Wednesday, January 30, 2002) through 150mm Argo at 210x. To double my pleasure, the GRS also could be seen trailing the perfect little dot of a lunar shadow across the planet's SEB. If you look carefully at the following sketch you will see Europa at right - on a line with the SEBs. Meanwhile, the shadow falls on the SEBn. So there is some slight inclination to Europa's orbit (vis a vis the Sun).
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Having started the evening with one bright planet, I wanted to make sure to
sketch the others. So, next stop was Saturn. To be frank, Saturn is not one
of my favorite "sketch" studies. There really is no easy way to handle the rings.
The image at right started with an ALPO (Association of Lunar and
Planetary Observers) sketch blank. It's probably intended for sketching what
little in the way of cloudtop features are susceptible on the planet. But my
interest lies primarily in the ring system. So I made do...
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I've been spending a lot of quality time with Jupiter as of late. The evening's view was
unexceptional, EXCEPT for a transit by Ganymede along the South Temperate Belt. Io transits are quite common. But over the last year or so, I recall seeing maybe only two other Ganymede "rites of passage". And they were all spectacular! First, the shadow is much larger. Second, it progresses very s l o w l y. Meanwhile, Ganymede tends to lie well ahead of its "dark twin" on the planet below.
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Tonight's view of Jupiter was unique in a number of ways. First I don't believe I've ever seen so many of Jupiter's belts in one sitting. Second, I confirmed the fact that detail seen along the SEB and NEB is more easily discriminated at 360x than 210. Third, I was able to run Argo all the way up to 650x and still see the NTB, NEB, and rift in the SEB - quite unexpected! Fourth, for the first time I saw some "filligreeing" along the northern frontier of the NEB and in the SEB rift. (Filligreeing gives a sense that the two EB's are "brushed" by a feather...)
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Had a rather interesting experience with the seeing and Jupiter this evening. Executed the following sketch at about 9:00PST under 7/10 seeing with high transparency (5.5 ULM) using 210x.
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Two nights ago the seeing improved enough to give a decent view of Jupiter once it entered the middle third of the sky. It had been awhile since I sketched anything of the planet so I grabbed the clipboard, turned on the outside light and went at it. Here's my best shot at what I saw around 9:30PST on the 16th of January 2002:
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Even with Jupiter only 20 degrees above the northeastern horizon, it too gave extraordinary views. All belts (but one) were visible. (Even the wispy equatorial belt.) SEB cleanly rifted. NEB showed internal barges and edge irregularities. NTB a nice thin, high contrast dark band with clear variations in width and depth of contrast. STB and SSTB directly discernable. Variagated polar regions. All but the NNTB easily seen at 180x. 210x. 360x. 540X!
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... the following sketch of Jupiter ... is illustrative of what may be seen on a good night (7+/10) stability, through a well-collimated scope (in this case 150mm MCT Argo). High magnifications were used (most detailed view view 360x, drawing at 210 to simplify manual tracking). No colored filters were employed. South is up.
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Sky stability was excellent this morning. Luna's limb was even stabler than last night (I'd say 8/10). Jupiter edge nice and sharp - though atmospheric water may have detracted a little. (For instance, once Io entered the SEB rift it was gone for good!)
But Io's shadow preceded it across the planet's girth with fine definition (Like a dark hole burrowing through the atmosphere.) After watching it progress for awhile, I decided to make a sketch. As it turned out, after a misstart in getting the band positions right, and some forty-five minutes later, the GRS rotated in and I included it too. So there is nothing scientifically accurate about the sketch. (Just a composite impression of what I saw as I followed the transit...)
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While Jupiter was not more than 40 degrees elevated above the western horizon - Saturn was half that. This detracted somewhat from the view. Even so, Cassini was quite sharp at times, the SEB was very distinct, the planet's shadow on the posterior east ring was nicely delineated, and a bit of the inner dusky ring was possible. Essentially, the nicest view of Saturn seen since late January. So all in all, the drawing at left shows how a primetime Saturn looks in Argo on a slightly better than average night (6/10). While that of Jupiter equalled (or perhaps slightly surpassed) that seen on a solid 7/10 night near opposition last year.
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Knowing we will lose the last of the decent views of Jupiter within a month, I spent almost an hour in slack-jawed jubilation executing the humble "labor of love" you see at left. While sketching, I mentally ticked off the list of features seen: Belt edge irregularities in both the NEB and SEB. Obvious split of the SEB into three lesser belt zones. A small light oval at NEB east. The EB bisecting the EZ. Faint corriolus lines leading into the EZ - especially from the NEB. A nicely delineated NTB. An NNTB almost completely distinct from the NPR. Nice blue gray contrast gradients leading toward both poles. Had the planet been a little higher - under the same conditions - I have no doubt that a plethora of intra-equatorial belt detail would have been revealed. - Something to look forward to next cycle...
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As you can see, I did get a chance to record a sketch of Jupiter. At the time, Jupiter hung perhaps forty degrees above the western horizon. Sky conditions were slightly better than last evening. Both nights revealed the split in the SEB. However, tonight the split was more obvious. The NTB was also visible. As you can see, a huge clot of material lay right on the central meridian of the NEB. Portions extended south into the EZ and north into the NTZ. Contrast was also quite noticeable. Delineation between the NNTZ and the NPR was also a little more salient this evening. Jupiter - unlike Saturn - seems to be leaving behind a few traveling gifts as it heads west into the sunset.
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A sketch of Jupiter under 5/10 stability skies with Io just off the limb: The real view displayed both high and low sky-frequencing blurring. Low frequency turbulence is seen as edge-blur (and sometimes edge-boil). High frequency blurring runs all the details though the blender. The result is just the two equatorial belts and polar regions. Occasional, during moments of rare stability, I could make out edge irregularities in the EBs plus thinning (splitting) of the SEB. At no time could I discern the NTB (most obvious of the minor belts).
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