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telescopemullet
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Re: Uranus cloud bands in a C8 new [Re: starrancher]
      #5691262 - 02/20/13 04:26 PM

I still love how Stan continues to favor using a C8 over a 106cm scope on top of the world. So absurd.

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ZielkeNightsky
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Re: Uranus cloud bands in a C8 new [Re: telescopemullet]
      #5691453 - 02/20/13 06:13 PM

Moderators, please. - like children.

Edited by ZielkeNightsky (02/20/13 06:15 PM)


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David Knisely
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Re: Uranus cloud bands in a C8 new [Re: LivingNDixie]
      #5691522 - 02/20/13 06:47 PM

Quote:

Quote:

David Gray posted:

Quote:

With reference to honesty: David Knisley’s remarks regarding Stanilas’, Abel’s and my observations on the ALPO-Japan site “of these three I think Paul Abel’s are worth noting:” “That is refreshingly honest.” Am I to take it that we other two are to be judged less honest because on this occasion we did not ‘qualify’ our drawings with such a statement?




It is honest in that marginal "detail" on a planet that may be thought of as questionable by the observer is mentioned as being questionable up-front. I can stare at one of my color drawings of Uranus I have done with my paint programs that are deliberately done to show a small but totally blank disk with a little limb darkening and still occasionally "think" I see hints of very faint details coming and going. This is basically the effect of the eye and brain putting in fleeting detail that isn't really there. If I blow up that disk on my monitor, I see that "detail" vanish, as again, I started with a disk that was deliberately made blank. I know of the effect each time I view a small and difficult target, so unless I am absolutely sure that I can repeatedly see some detail, I don't log it as being there. Saying that one may or may not be seeing something is honest and fully understandable. I have glimpsed the "spot" on Ganymede in only a 9.25 inch aperture and when the seeing allows, additional detail on that moon in my 14 inch is visible at the high powers I like to use. When Mars is halfway decently placed for observation, I have done some fairly good drawings of the notable detail I have seen on that planet, some of which I have posted here on Cloudynights. However, even after repeated observations over the many years I have been an amateur astronomer, in apertures from 20 cm to over 60 cm (8 to 24 inches), I have yet to see any detail on the disk or Uranus other than the ever-present limb darkening. That is my honesty and my truth. Clear skies to you.




Your computer drawings of Uranus and your eye telling you there are details that you know are not there. I will say again what I said earlier, the features people see on Uranus is no different then the features that Lowell drew on Mars. Our minds try to make patterns from things that don't have any patterns.

That being said I really wish there was something to see on Uranus, but all the photography from observatories and spacecraft really show that is not the case.




Well, there is a little difference between the "canals" and detail on Uranus. With the canals, it was fine mottled detail that actually exists but which the eye/brain tended to merge together to form an apparent linear feature. With Uranus, there just is the eye/brain doing its best to attempt to show a small nearly blank dim bluish disk under difficult conditions. Once you get down to a certain small scale and lower light level, the "noise" from that "organic" detector/processor starts to show up, so you just have to be aware of it. Other than that, the only thing I can say for certain is that, in apertures from eight to 24 inches, I have not ever seen anything on the disk of Uranus at all (other than limb darkening). From all the time I have spent observing the planet under at least halfway decent observing conditions, I just don't feel that there is really anything there to see in the first place. Clear skies to you.


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telescopemullet
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Re: Uranus cloud bands in a C8 [Re: ZielkeNightsky]
      #5691755 - 02/20/13 08:59 PM

Quote:

Moderators, please. - like children.




There's nothing to moderate here. Stan is asserting that he favors a C8 over a much larger apeture instrument situated in a locale better suited for viewing than his. I think most rationale, logical, and scientifically minded people would agree his assertion is absurd. We can cast doubts on assertions can we not or is it because stan is far out on a limb and continues with his drawings that his claims are untouchable?

Edited by telescopemullet (02/20/13 10:39 PM)


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azure1961p
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Re: Uranus cloud bands in a C8 new [Re: ZielkeNightsky]
      #5691877 - 02/20/13 10:31 PM

Quote:

Moderators, please. - like children.



Lars,

Your post would have more merit if you contributed anything at all to the topic. There is nothing wrong with debate so long as its not pointed or personal . The thread has had its moments but frankly if the most you can add constructively to a thread on low contrast feature detection is parental posturing you might want to self moderate.

Pete

Edited by azure1961p (02/20/13 10:34 PM)


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stanislas-jean
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Re: Uranus cloud bands in a C8 new [Re: azure1961p]
      #5692105 - 02/21/13 01:52 AM

What is absurd, gents, this is the fact of not analysing a problem and make all your confidence on your own personal eyes that are irrefutable, by definition.
This is not arguments.
You could watch using the 2.5m of Mount Wilson, this shall be same results.
The question is to capture 2% levels around at the red channel.
The people can argue on the personal SNR ratio on the problem but consider also that some can have better (and tested in actual conditions and on long distanced targets).
Remember the fact that imagers also collected in pure R channel the banding pattern and in B channel also. And lot of people trying to capure only in R channel failed also.
It's time to revise judgements about, built on unconcistencies that you believe in.
Stanislas-Jean


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freestar8n
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Re: Uranus cloud bands in a C8 new [Re: azure1961p]
      #5692171 - 02/21/13 04:12 AM

I don't want to comment on the detection likelihood here, but there is a recurring theme in observational threads that it is hard to do much scientific confirmation since the ultimate data involved is what appears after the eye-brain perceptual process has done its thing - and it's hard to capture that "image."

But I think there are somewhat rigorous ways to do "blind" tests of perceptual issues - and one way is to change the image in controllable ways and see if the perception - or sketch in this case - tracks that change. In this case I think that just an extra mirror in the path would change the parity of the image so that the diagonal bands would appear to go the opposite way relative to the gibbous phase - and the N/S orientation. I'm not sure if this would work, but for example if you used an erecting diagonal of high quality along with a simple mirror diagonal, the image parity would be opposite and the sketch should reflect that. The diagonal in use would need to be hidden and the focus roughly pre-set so the observer had no indication which was in use.

If the erecting diagonal was not of adequate quality - or something - then this wouldn't work. But my main point is that even if human perception plays a key role in detection, there are still ways to get a handle on whether or not the detection is a true positive, by altering the image in controlled ways unknown to the observer, while at the same time knowing the ground truth orientation of the bands. In Lowell's time there was no ground truth to reference regarding Mars, but in this case there is with respect to Uranus - just as there is with known close doubles - etc.

Frank


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stanislas-jean
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Re: Uranus cloud bands in a C8 new [Re: freestar8n]
      #5692198 - 02/21/13 05:16 AM Attachment (14 downloads)

If you perform such tests over few months this can cover a maximum of situations.
Stanislas-Jean


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Rich (RLTYS)Moderator
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Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5692313 - 02/21/13 07:54 AM

To All, Lets keep this discussion friendly or I will lock this thread.

Rich (RLTYS)


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David Gray
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Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5692359 - 02/21/13 08:53 AM

Here is a message passed on to me by the then (2003) BAA Saturn/Uranus/Neptune Section director David Graham from that severe skeptic Willliam Sheehan (“Planets and Perception” etc)


Hello David - Bill Sheehan was at Lick this summer to observe Mars but I also persuaded him to have a look at Saturn. I will relay his drawing for you to see. I intend to put it in the JBAA in due course.
All the best,
David
----- Original Message -----
From: Debb & Bill Sheehan
To: 'Dave Graham'
Sent: Monday, November 24, 2003 1:02 AM
Subject: RE: Saturn
Hi, Dave,
Thanks for the condolences, which I passed along to the rest of the family.
The Saturn drawing shows detail I was sure of – and within the limits of my artistic ability. It’s a tough object to draw because we think in terms of straight lines and Saturn’s all curves. The magnification used was 655x.
I did look at Uranus with the Lick refractor, since it wasn’t far from Mars and was easy to find, and had the distinct impression that there was a dark equatorial belt, which I thought was peculiar since one is used to seeing bright equatorial zones on the Giant Planets. You can pass along to David Gray my confirmation and also my high esteem for his observational and artistic abilities.
[bold mine]
Hope to see you next year as I’m likely going to be in the British Isles at some point around the time of the Venus transit.
Yours, ever,
Bill


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David Gray
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Re: Uranus cloud bands in a C8 new [Re: David Gray]
      #5692379 - 02/21/13 09:09 AM

This is from a pm recently to Rick Woods (Hi Rick!)

Here is a link to a NASA document see especially the chapter ‘Why Image Uranus’ by Belton & Vescelus page 299 (pdf page 28), which has some pertinent comments re. visual and Stratoscope II.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770075072_1977075072.pdf

In time (maybe next apparition) I may post something in detail pointing out what I consider to be the optimum requirements for getting at said reality. It is a long list and I can see the protests now – why so much bother to see so little; but my answer will be it is the only way to get to the bottom of it! I can’t help knowing which way the banding is oriented and if I am suffering from illusion and it is in the main consistent with this angle. So this only leaves two factors: I am fooling myself or being grossly dishonest.

I can say something about seeing what one wants to see from my early observing days1961 on:

Mars: I was so beguiled by those Lowell spider-web canal drawings that when my 10” Newtonian came along (1964/me age 20) I eagerly anticipated the 1965, albeit alphelic, opposition; and was gutted to only see relatively disparate irregular well-contrasted features and a few rather coarse linear features. In short I was desperate to see these ‘webs’, but all my wishful thinking would not put them there in any kind of seeing and pretty much left Mars alone till 1988 – BAA Mars director Richard McKim can attest to this!


Uranus: here I was expecting to see a green/blue smaller version of Jupiter (I think some do now!) after seeing a picture in a book at school c.1955; also I knew nothing of the unusual tilt. My first good views in March 1965 irritatingly kept giving a north/south dusky band which I finally decided to draw in the 1966 apparition then left it alone till 1969 when I got presumably an EZ and two narrowish belts: March/April . With it steadily going south in subsequent years and apart from a good view in Dec. 1977 left it alone till 1985 (still v. low in S.) and have followed it since.


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stanislas-jean
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Re: Uranus cloud bands in a C8 new [Re: David Gray]
      #5692380 - 02/21/13 09:12 AM

Interresting and instructive: what we collected also.
Thanks David.
Stanislas-Jean


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David Gray
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Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5692443 - 02/21/13 09:59 AM Attachment (12 downloads)

Thanks Stan,

Extract from a message just too late for the locked “Uranus Season......” thread

[Voyager 2]:
Similarly [to Stratoscope II] I keep seeing reproductions of the Voyager polar view with captions such as “….. adjusted as it might appear to the eye”….!! Whether on the monitor or printed page I feel we need to view these with the same caution we should be applying at the eyepiece.

“Adjusted to match what the eye sees”: now there is a can of worms. Whose eye – one of the team, someone passing by, the canteen maid – hopefully those with at least “normal” vision to be serious? Conceivably “normal” falls short of cutting it with this planet; and so many abuse their eyes – health-wise, diet-wise and otherwise (monitor-wise?)!


Not sure how it will come out but attached is a 1993 letter from the late Andy Hollis director of the BAA Asteroid & Remote Planets Section.


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leviathan
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Re: Uranus cloud bands in a C8 new [Re: David Gray]
      #5692488 - 02/21/13 10:33 AM

Thank you for interesting postings, David !

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azure1961p
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Re: Uranus cloud bands in a C8 new [Re: leviathan]
      #5692631 - 02/21/13 12:17 PM

All wonderful accounts but that still doesn't bring any substantiation to belts drawn in even mediocre seeing with an 8" sct and a 6" refractor with as much regularity as viewing Syrtis Major. It is difficult for most anyone to believe regular (every time a man observes) that not only are eq belts observed but temperate polar details, "bubbles" (Stan's words) or giant scalloped voids in these belt regions not to mention conspicuous white spots - and all in the confines of a few months - not decades.

David I highly doubt anyone has doubts your work. I know Im a fan - particularly on your Galilean moon drawings. The impression that is under question here is the availability of such things through modest instruments bordering on small with regularity unwavering and steady.

Pete

Edited by azure1961p (02/21/13 12:19 PM)


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telescopemullet
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Re: Uranus cloud bands in a C8 new [Re: David Gray]
      #5692640 - 02/21/13 12:22 PM

Quote:


I did look at Uranus with the Lick refractor, since it wasn’t far from Mars and was easy to find, and had the distinct impression that there was a dark equatorial belt,




The above observer was using a 36-inch (assuming the referenced Lick refractor does indeed mean The Lick Refractor)and he stated he was given the "impression" of a belt. He did not write that he saw a belt(s), big difference.

Compare this to stan who sees banding 100% of the time no matter what the conditions is scopes of very small size.


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David Gray
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Re: Uranus cloud bands in a C8 new [Re: azure1961p]
      #5692696 - 02/21/13 12:57 PM

"All wonderful accounts but that still doesn't bring any substantiation to belts drawn in even mediocre seeing with an 8" sct and a 6" refractor with as much regularity as viewing Syrtis Major. It is difficult for most anyone to believe regular (every time a man observes)"

Yes I know this thread's specific is 8" SCT (my 10" Newt comes close)but it concerns me when it is claimed that there is "nothing to see" full stop - to me: bland yes, blank no! I will check it out next apparition with a 6" off-axis stop.

I do not know if it is everytime Stan observes certainly not with me; but I only report views in good seeing. However I did endure with bad-seeing views this apparition on some nights to check out possible illusions and had some interesting impressions that may cheer the doubters! This needs more follow up and hope to post my findings next apparition.


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stanislas-jean
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Re: Uranus cloud bands in a C8 new [Re: telescopemullet]
      #5692697 - 02/21/13 12:57 PM

When you will understand something physical, we will continue, this was answered here before.
Pete, white spots etc... mean like black cats and wording matters a game from you.
We are in the very light grey tones fields.
Read again the posts since the beginning and answer the questions raised, if you wish.
Please consider that all scopes in use were characterised, seeing quoted and you know the conditions well assessed and tested.
Stanislas-Jean


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leviathan
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Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5692738 - 02/21/13 01:13 PM

I think that a lot also depends on the experience of observer. Many people only see 2 or 3 belts on Jupiter at a first time, then they start to see polar caps, then festons, ovals and other small details. I mean it comes with experience. And you also need to know where to look to see it.

I honestly observed Uranus only several times. And all critics here should observe it at least as many times as Stan and David did to say that there's nothing to look at. IMHO


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David Gray
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Re: Uranus cloud bands in a C8 new [Re: telescopemullet]
      #5692761 - 02/21/13 01:25 PM

Yes it was indeed the 36" refractor. Perhaps if he had thought to dim the image he may have seen even more! A factor that I suspect those using large and very large telescopes need to address (covered in an earler post of mine -page 10)

David Graham used that very same 36" to look at Saturn in 1995 and told me that all (very experienced) observers present found no difference in intensity twixt the n & s halves of the EZ. But it was established with certainly there was a marked difference also to Hubble - I got it on 57 nights! This was obviously due to an extremlely over-bright image in the 36" washing out the differences.

Not Uranus I know but the very weak features here are easily lost in 'glare'. As the planet climbs higher each year I am finding it too bright in good transparency even with the split light path of the binoviewer and x535 - often resorting to the apodizer; the features are that weak.
See also my earler post to Azure61p.


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