Jupiter 9 Dec 1730UT

Those 3 ovals were not as well resolved as last time, especially the trailing two. Some darker patches noted in the north and possibly one lighter patch. Unsure, but I saw something up there. I thought I glimpsed a white spot in the northern NEB near the preceding edge.

The festooning was difficult with some fairly prominent ones. There appeared to be some interactions among them. The EZ trailing half seemed to have a very faint blue hue to it. I thought that was amazing.

And Oval BA is on the trailing edge. If you look closely you might see a small white dot. I left it difficult to underscore it's difficulty. It's there if you can see it, just like me. And it's a story in itself. It was so very difficult this time, especially compared to last. Much more on that later, it was amazingly difficult.

I have to admit cheating a little on Io. I did observe it as seen, but it was a half hour or so before the sketch. I included it because it was nice.

More later, this sketch ate up all my time. Gotta run.

Edit: System I 306, System II 316, 240x (8mm TMB II), seeing Ant II.

I'm actually starting to like the 8mm TMB Planetary II at 240x on Jupiter. It gave a more vivid orange hue to the faint belt preceding the GRS and it seemed to show oval BA a tiny bit better than the 12mm HD Ortho with 1.6x Barlow combination at 260x. Of course, the 10mm HD Ortho and 1.6x Barlow was lower power and in the magic range of 30x per inch, but while contrast is better the image is smaller. And oval BA was seen less often. More experience is needed to be more sure.

Also, in a hurry, I left out some faint hints of rifts below the major festoons from the original sketch. Edited to add them in. Lastly, there are apparently no bright feature in either the northern region nor along the northern NEB at this meridian, not that I could find in any images, anyway. Eye tricks, maybe. I pushed hard on this sketch.

Very nice Norme . This sketch really shows of the extent if the festoon wash - really broad and vivid compared to other times. You moved Io - lol - see now if a guy photoshopped such a thing he'd be stoned!!!! I get it though and you were making a composite view of the best of the all seen over the session. Those white spots - I'm still bothered at never getting a clear shot at them last year and instead getting that soft winter dither of detail that marked their presence. This is a nice piece - love the split belt in the north polar region - the wavering thickness must've been a nice catch .
The two tone SEB is terrifically rendered with a very fine degree. I see the variations in intensities along it as fringy detail and then that transition to the bold swath that is the robust SEB we all know and love. The pale washed out but delicately edged out SEB region though is terrific.

You've been belting them out Norme. And again just my blurry one try and clouds rain and snow since.

Pete

Pete, thank you. The SEB seemed a bit less active. Not much going on. There was a bit of a southern border with a darker lump near the meridian. Yea, those white spots are a tad more difficult this year and so far. I think I might have glimpsed one oval south of BA, but not enough times or with the certainty needed.

The seeing is not quite as nice, though it's pretty good. It's amazing the difference between 8's and 9's (Ant I, basically) and 7/10 Pickering which seems to be getting into Ant II. I am having to work a little harder observing and I keep feeling I am just missing something. It's okay, the images are pretty fine, still, just gotta work through it. Transparency was highly variable last night and the sky seemed bright even in the finder. I think this was a major contributor as Io's ring was pretty stable (after is left the disc) indicating pretty good seeing.

I'm doing a work up on BA, it should not be that hard. Or maybe it should be. Notice most of my sketches are now either "complex" of "difficult?" Yea, it seems it's taking more work to really observe the planet these days. Things have changed, though. I am operating is slightly lesser seeing and experimenting with higher magnification, too. So...

Okay, observing oval BA back on December 2nd was actually very easy. It was just there, even though I did not recognize it. It had a bit of an elongated appearance. I am convinced this was due to the presence of an unresolved oval just to the south. Together they formed an unresolved elongated structure.

That oval has moved on, or Oval BA has. In any case, they are now separated and oval BA is much, much harder than previously. Again, I could barely see it in the central meridian (moved back on the sketch) at 240x (8mm TMB II) or 260x (UO 12mm HD Ortho and 1.6x Barlow), or even lower trying all sorts of eyepieces including Orthos and Plossls. It was just tough to see, but it could be seen.

The question becomes what is being seen? Doing some pixel measurements, Oval BA is about 1.8" arc (454 pixels for Jupiter at 10 pixels/arc second, BA is 18 pixels north to south.) Okay, that's plenty angular resolution to resolve in 150mm aperture. The problem is contrast between BA and the surrounding cloud it's embedded in. There is not much difference in contrast between them, at least visually.

If that's so, I should not see BA at all. It would simply blend in with the slightly darker clouds and disappear. However, I did manage a very tiny white speck that was only slightly easier than any other white oval. And it appeared about the same angular size as a white oval. (Smaller than the three shown in the sketch, but about the same as others south of the GRS.) So, somehow, oval BA is becoming visible despite it's hue and contrast against the surrounding cloud.

Oval BA is slightly brighter than the surrounding cloud, so if any diffraction is occurring it should make BA larger and easier to see. Here, it's almost as if the dark bands are encroaching on BA squeezing it to a very small size. That may not /should not/ be happening. SO, I am left with the presumption I am seeing the somewhat brighter and definitely smaller 0.8" arc central core.

I really wanna get Eddgie to chime in and help with what was seen. This is confusing, again. Oval BA (in images, anyway) looks as though it might stand out from the surrounding cloud. I doubt it does, visually, and this explains the extreme difficulty (along with less than perfect Ant II seeing) observing it. Yet, even if it's contrast is low, it was indeed visible as a very tiny and very fleeting bright spot against that same darker cloud that embeds BA.

Image by Xavier Dupont courtesy ALPO Japan. You can see that white oval is no longer just south of BA, I suspect BA is lagging a bit since I think the winds at these latitudes blow toward the preceding limb. (Right?)

I think your seeing the brighter middle Norme. And what little area that is at that size might be encroaching over the darker value giving an impression of the full size of BA but not exactly it.(?). Those two contrasts of the darker edges of BA versus the surrounding cloud deck visually would be way closer of course than the image infers. Its SN interesting perception/diffraction problem anyway.

Pete

Nice work Norme,

I have a TMB 5mm and like the eyepiece. For the $40.00 I spend it is a bargain. Mine gives me 240X on my dob.

I have to say your captures of the festoons are really lovely. Always enjoy reading your observation reports and viewing your sketches.


Ken

Ken, I much appreciate your kind words. So much so, I'm replying on a small android screen (spelling and fat fingers, you know). Thank you.

Pete, not sure whats going on. BA should be huge in comparison. And that lighter core is not that bright. Weird. Really, have you ever blown an eyeball? After a half hour or so, my vision totally went blurry. Man.

Playing with Aberrator, this is the best I could come up with.

Norme, I love following your trials and tribulations with the BA. Meanwhile, the festoons seem to be getting better and better. And I'm really loving the way the NTB is invading the NTZ on the trailing side of that sketch.

After this snow finishes accumulating we are in for a big ol' arctic blast. The skies should be clear, but let's see if I'm brave enough to try for Jove.

Ok, rember the first rule of contrast tranfer. A white line on a black bacground gets wider, and a black line on a white background gets narrower.

Black and white are used for MTF because both are "Perfect" states for the task of expressing the systems performace.

Black in MTF and contrast tranfer represents a complete lack of light being emmitted from the target detail.

And for extended objects, this is rarely the case. About as close as we come is the gap in Cassini Division and this is why small telescope can still resolve Cassini.

So many things we see as "Black" are not really black at all. Umbra on sunspots, shadows on the moon, and some other details.

But on an extended target like Jupiter, ever square meter is a light source.

And when you have a darker source next to a brighter source, the effect is that the brighter source does not always get larger (unless it is really bright). If it is not all that much brighter than its neighbor, the light from the border of the neighbor and the light from the target detail mix together and you get a very graduated transition. If the target detail is an oval, you might seee only the very center after the blending has destroyed what would look like a very sharp border in Hubble.

Another way to think about this is suppose you had a nuclear blast on Jupiter. While the fireball itself would be to small to resolve angularly in an earth based scope, if it was bright enough, we would see it as being the size of an Airy Disk! Its relative brightness to the background would be so high that it would almost be like a white line on a black background and it would apear wider than it really is. If the blast were truely bright enough, we would see it as an Airy Disk, with a diameter equal to the resolving power of the telescope. Hence, it would appear wider than it really is (White line on a black background).

But that is the extreme case. Only when a comet crashes into a planet do we get something that could create this kind of brightness.

For any detail emitting or reflecting light, blending at the border between these to objects will reduce the apparent size of both details. How much blending that takes place is a function of the amount of energy each emits.

This is why a very small telescope can show a black shadow transit of a moon on Jupiter's disk, but not show a similar sized oval (and think about that. Your scope easily shows a black shadow transit, yes?). Here, the energy from the bodering area bleeds into the shadow, but since the shadow area is only emmitting perhaps 5% of the enegery (again, this detail is not 100% black, we still see it as very dark against the background).

But if you measured it in images taken with a small scope and a much larger aperture, the diameter of the shadow would indeed appear much smaller in the smaller scope. Just the opposite of your nuclear fireball, which would appear much larger than it really is.

But for complex shapes and textures where the contrast difference starts fairly low (perhaps less than 30% to 40%) both sides of the border are emitting light that gets diffracted by the aperture across the border from one neighbor to the other.

The result is that for most lower contrast detail the targets always get smaller angularly.
The exception is a very bright emitter on a fairly dark background, or equitorial bands on Jupiter. Very thin but dark bands on a very ligth background, can indeed get hard to see, and if the band is irregular, in a small apeture, it might appear more as a series of dots than an irregular line. Again, our discussion about resolving a feature and detecting a feature comes into play.. The small scope observer would report resolving a row of spots, while the large instrument observer would report resolving a line. Same detail, but two different levels of resolution.

Back to basics.. White line on a black background gets wider, black line on a white background gets narrower, but if both lines have brightness, they simply blend together and if they are close in brightness, the simply smoothly transition one into the other. In the case of an oval on a low contrast background, only if it has enough diameter and enogh starting contrast to preserve some of the full contrast at the center will you stand a chance of seeing it.

And remember the difference between seeing a moon's shadow an the moon itself when over the disk of Jupiter. The shadow is easy, even in a small scope, but the moon that casts it is not much different in brightness to the surfeca of Jupiter. It will take a larger apture to preserve enough of the contrast for it to be seen crossing the disk.

Not sure I answered you question, but MTF uses black and white lines to get a "Best possible Case" and extended detail on planets is almost all refecting some light, and often almost as much light as the neighrboring detail. It gets very complex very fast.

Ed, excellent. Makes great sense. I was assuming BA would overpower nearby dark clouds. Ok, that's wrong. Beautiful explanation. More later, got great seeing tonight and partly cloudy skies. Back later.

Jason, its an interesting trial with BA. Wow. So difficult, more so than last year. I'd like to see more reports and attempts at it. So dawn those pink thermal undergarments you're so proud of and hit it. (I have a pair, too. No need to blush.)

Sry duplicate posts.

Another superb drawing Norme

Norme,

Nice sketch of Jupiter .

CS,KLU,

,

Tom

Norme,

The fine nuances of color and shading in this sketch is beautiful. The little cluster of 3 ovals is unique, what a great catch. Io in the sketch with it's shadow adds interest to the sketch with perspective and action. And you caught Oval BA on STB. I also what you meant by blue haze in the EQZ. Another excellent sketch.

Dean

Dean, yes, a few nights prior those three ovals were better seen. This night they kind of ran together. The white dot on the cloud representing oval BA is misleading in the since it was that tiny but not nearly that easy.

I am hoping you can catch the wild festooning, from the primary streamers to some fragments south of the EB and all the way down to the unresolved activity (I believe) giving the EZ a faint blue tint. It's quite beautiful.

Norme,

A sweet looking ,detailed capture of Jupiter.
I love the color and details.

Frank

Frank, I'm chasing you around the forum saying thanks. Not stalking...