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Jupiter's EQ Zone is not White

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#1 Asbytec

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Posted 11 November 2012 - 04:27 AM

Normally when we sit at the eyepiece and Jupiter illuminates our eyes, it appears quite bright. Maybe we tend to begin estimating relative hues with the brightest areas setting the base line for what we call white. Then we evaluate all other colors, hues, and saturation based on those initial conditions. Right? I think this is what I do.

A recent discussion between George and Dean concerning a yellowish hue in the NTrZ led me to explore the area. I had seen this hue, though called it bit more ruddy than yellow. But, I hadn't really noticed it, lately. The zone appeared to be pretty much white and I sketched it, and the SEB, as such.

So, I began looking for brighter whites across Jupiter's face. Low and behold, and as luck might have it, there certainly were more pure whites in the SEB preceding the GRS that was rolling into view.

Once I set this as a baseline for white, I was astonished at the color I had been missing in the equatorial zone. It's not white at all. It's actually a very soft, pale yellowish hue. A very distinct SEB northern border with the EQ zone was indeed streaked with very white features. A bit less white was seen bordering the NEB, too.

Gotta pay more attention to those details. When one does see them, it changes the face of Jupiter nicely. I can only hope the sketch does justice to this new found property of Jupiter. It's another of a string of "firsts" for me this year and I wanted to share it.

Sorry, but I spent a lot of time studying the EQ zone during this sketch and might have missed some other features. One feature I included, and will continue to include, is the fading of the belts in the limb darkening.

OH! That tiny dark oval following BA was very apparent last night. Normally I can spot it periodically. Last night, it held steady for long periods of time as it neared the meridian. At first, I wondered why the object was not easy, guessing it was nearly the size of a transit shadow and nearly as dark. Turns out, it is very much smaller. A mere pin point of a dark spot.

Thanks! Discussion on color perception, anyone? I am all ears.

10 Nov 1630UT beginning and CM sys 1 about 010. Seeing 8-9/10, transparency mag 4.5. UO 12mm HD Ortho, Celestron 2x Shorty Barlow giving 174x. Unfiltered.

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#2 azure1961p

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Posted 11 November 2012 - 02:49 PM

you really have come into your own with sketches. the last look I had it was a frothy white a year ago. the strongest hue I've seen ever was circa 1990 with this sulphur yellow grey band being the whole zone in ifs entirety. big difference from other times.

Your post hits on the point that its never right to make blanket assumptiins as it can blot out the finer reality of things. if its clear tonight ill see how fine I can go but weather sais building clouds... might be a 70mm evening. but I will look for subtle yellow.

pete

#3 Asbytec

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Posted 11 November 2012 - 08:22 PM

Thanks, Pete, yea noticing that sulfur yellow hue really changed Jupiter for me. I am not sure if the whole zone is the same hue, but gonna find out.

Good luck with the weather, Pete. Jupiter is quite exciting.

#4 frank5817

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Posted 11 November 2012 - 09:03 PM

Norme,

Another very fine Jupiter capture. Great detail across the visible disk.

Frank :)

#5 Asbytec

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Posted 11 November 2012 - 09:21 PM

Thank you, Frank. I spent more time studying Jupiter's varied hues than sketching. I think sketching just became more difficult. :)

#6 Jef De Wit

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Posted 12 November 2012 - 05:35 AM

Discussion on color perception

I read this question before going out last night so I paid a lot of attention to the colors (seeing was not so good for details...). The two great belts look really brown to me (in your sketch the are grey on my screen). And the festoons are darker (blue). But this is no critic: eyes are really personal. And maybe the difference in apperture plays also (mine is 30 cm).
Althougt I prefer manuel sketches (old fashioned :grin:), you always manage to see a lot of details... so keep up the good work.

#7 Asbytec

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Posted 12 November 2012 - 07:38 AM

Jeff, you know, to me all Jupiter's colors are very close to grey scale. In fact, maybe the most prominent colors are in the north and south polar regions. Brown and grey, respectively.

Yes, the festoons are very distinctly blue - I might have done them too baby blue. This is a result of my technique of layering colors until they turn darker. It helps with achieving the soft shading sometimes seen. But, if the festoon is weak, it get's less "paint" and stays more baby blue.

The belts are pretty much grey scale in a 6"...to me. But some hint of ruddy hue can be seen as the eye really get's into the observation. Adapted or whatever...

I do the sketches in more bold colors then remove some saturation to achieve an approximate grey scale while leaving enough of a hint of color to get the point across. It's hard to color something for all monitors.

But, you know, I was just pleased to "learn" to see color in the EQ zone which I always considered "white." It's not white, at least not near the GRS right now. To see this difference in hue was a real eye opener. Seeing these softer hues means more detail can be seen.

It was an exciting observation in that sense, so I was wondering if others had similar experiences and they gained time at the eyepiece with Jupiter.

#8 Chopin

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Posted 12 November 2012 - 06:11 PM

Norme, every new sketch of yours impresses me further. I will echo what others have said, regarding both detail and colors you are seeing a tremendous amount. I hope when I get my first A-II seeing session that I can record half of what you do. Keep us going, bro!

#9 Asbytec

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Posted 12 November 2012 - 09:43 PM

Jason, It seems Jupiter is better this year. It could be several reasons.

First, there is more to see this year. The festooning is more prominent and the rift in the NEB was not really apparent last year. Last year, the NEB sported a bunch of barges, but not much else. And the GRS wake was evident. This year, whoa, the EQ zone belt and more is visible.

Second, it's gotta be some experience and training. This is my second season observing Jupiter, followed by Mars and Saturn earlier this year. This season and last, I observed planets very frequently and almost exclusively.

The scope is perfectly collimated and cooled, and it's operating in nearly perfect seeing for a 6" aperture. So, those factors, plus a little effort and perseverance are really paying off.

I also suspect one modification to my scope is playing a role, too. But, it's hard to quantify. In fact, at first I was unsure if there was any improvement at all. But, there indeed might be.

Even when seeing drops to about 7/10 or below during some rough moments, they are difficult to see. But, when the atmosphere just seems to freeze into place more often and for longer periods, they show up. But, it still takes a good while (about an hour) to really note all of those features. For example, it took several crisp views to kind of see the NEB rift was indeed segmented and not one single feature.

But, all those features are, indeed, visible in a 6" aperture when it all falls together.

#10 Chopin

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Posted 13 November 2012 - 06:38 AM

Jason, It seems Jupiter is better this year. It could be several reasons.

First, there is more to see this year. The festooning is more prominent and the rift in the NEB was not really apparent last year. Last year, the NEB sported a bunch of barges, but not much else. And the GRS wake was evident. This year, whoa, the EQ zone belt and more is visible.

Second, it's gotta be some experience and training. This is my second season observing Jupiter, followed by Mars and Saturn earlier this year. This season and last, I observed planets very frequently and almost exclusively.

The scope is perfectly collimated and cooled, and it's operating in nearly perfect seeing for a 6" aperture. So, those factors, plus a little effort and perseverance are really paying off.

I also suspect one modification to my scope is playing a role, too. But, it's hard to quantify. In fact, at first I was unsure if there was any improvement at all. But, there indeed might be.

Even when seeing drops to about 7/10 or below during some rough moments, they are difficult to see. But, when the atmosphere just seems to freeze into place more often and for longer periods, they show up. But, it still takes a good while (about an hour) to really note all of those features. For example, it took several crisp views to kind of see the NEB rift was indeed segmented and not one single feature.

But, all those features are, indeed, visible in a 6" aperture when it all falls together.



I'd say this is an important post for newbies. Specifically for understanding the amount of effort, time and patience that is required to reveal just one or two new details. Thank you, Norme.

#11 Asbytec

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Posted 13 November 2012 - 07:52 AM

:o

#12 chrisrnuttall

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Posted 13 November 2012 - 04:02 PM

use a white light for sketching, and frequently look at a white sheet of paper illuminated by the white light. It will stop you dark adapting and keep your colour vision working.

Norme, I used to own an ETX125 and Jupiter was very grey scale through that, but through my 70mm refractor and my 200mm newtonian the colour is bold and rich. I think it is a function of contrast, the ETX had a big central obstruction, and if there was even a little dew on the corrector then the view became totally devoid of colour.

you need a huge scope! :)

#13 niteskystargazer

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Posted 13 November 2012 - 04:46 PM

Norme,

nice sketch of Jupiter :).

CS,KLU,

:thanx:,

Tom

#14 idp

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Posted 13 November 2012 - 04:53 PM

use a white light for sketching, and frequently look at a white sheet of paper illuminated by the white light. It will stop you dark adapting and keep your color vision working.


Uhm, sounds like a good tip. Even though in a 10" with medium mag. (say, 230x) Jupiter is bright enough that you don't get adapted at all (the eye you don't use to observe is a different matter, of course)

Ivano

#15 Special Ed

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Posted 13 November 2012 - 05:13 PM

Norme et al,

An interesting discussion and one that is a natural by product of careful observations by visual observers like Norme preparing to sketch the target object. :cool:

I usually perceive the EZ as "pale" or "dull" (sort of) as opposed to white or bright. It's hard for me to find a descriptive word for it. Historically, observers have described the EZ in terms ranging from those I just choked out to "tawny", ocher, and yellow-orange.

You might find this an interesting read: observations over a 150 year period that show a yellowish appearance to the EZ in about a 12 year cycle. Here is a bonus: when you read this you will see the names of many, many legendary visual observers.

On the Observed Changes of the Colour of Jupiter's Equatorial Zone. :bow:

#16 azure1961p

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Posted 13 November 2012 - 07:15 PM

norme and chris - battle of tge avatars lol.

p.

#17 Asbytec

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Posted 13 November 2012 - 11:46 PM

LOL, Pete.

Chris, yes, color is all about contrast. And contrast is all about resolution, resolution is contrast. Normally we think of it as purely black and white, like resolving a double star. But, the thing that struck me above was discerning a slight tawny hue (contrasted with white) meant there were more features resolved.

My 150mm Mak CO is just under 30%...don't ask (but it is 41 or 42mm not accounting for the power of the meniscus.) :)

Jupiter is pretty much varying shades of grey in my 6", too. But, with care, the NPR is definitely a soft brown hue. Sometimes it really shows well. Same thing with the SPR, it's soft grey and often distinctly so. The Festoons are definitely blue.

The main belts are a bot more difficult to discern as color instead of darker grey. But, when the eye is in the "zone" they do have some ruddy hue to them. This is the hue I try to capture and replicate...then de-saturate back toward grey scale leaving just enough so other's can see a hint of color as I do.

Wow, yea, the ambient light argument. I am sure it helps, no doubt. To me, it's more of a distraction as I observe with both eyes open. I don't like seeing things in my other eye overlapping Jupiter in my observing eye...or out of the corner of my observing eye...which is not dark adapted at all, anyway. Using a flashlight to sketch ensures it does not dark adapt in the few seconds used to place detail on a sketch then getting right back to the eyepiece before Jupiter rotates further.

Michael, thanks for the read. Yea, to me, the EZ is bright and I think my silly brain immediately sets it as the baseline for "white." This was the revelation of actually seeing some "more white" features in the SEB. And it all stemmed from Dean and Georges discussion of a yellow hue in the NTrB. Seems Jupiter is basically more yellow or tawny, as Ivano had commented on. Exciting! :)






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