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Uranus cloud bands in a C8

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#201 stanislas-jean

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Posted 01 February 2013 - 01:33 PM

This a straightforward assessment.
Still the confusion between contrast transfer and resolution.
There is a tool for explaining this the FTM curves.
Please consider also that the 6" was able to catch the banding pattern, nothing else.
Uranus is mainly under the difficulty of capturing low contrast levels, about the resolution ability we have enough.
What is sure now over the 3 years intensive observation, contrast levels are fluctuing with time, featuring is changing. The contrasts levels turn around 2% maximum, visual channel, and this is the node of the difficulty, 2% on the planet not at the scope exit.
Conditions of observations are crucial and light glaring has to be avoided. Seeing levels must be also well quoted sothat the observation of a close star and its diffraction pattern is to be performed. Under 10/10-6/10 range the observations are practicable, there are always calm times under these 6/10. David exposed very well these points more than me and his valuable experience.
Now for being positionned against an own ability to catch tiny low contrasted features like on Uranus, everybody has the open possibility to visit a Laboratory for assessing their eyes, that I did. If you are courageous you will refer to previous posts of me with the lighting conditions necessary.
This shall be more prolific rather than futile discussions, it will cost you 300 about for making this an afternoon. You will see what is glaring light with measurements with the optician, stress conditions, light accoutumance, etc...
I was dubitative before, pretty confortable now.
Up to you if you want to progress or staying still on outmodel views.
I donot know a telescope that shows a contrast level more than it is on the planet visually, except with using electronic devices.
Now for sketching, sorry for the amplified appearance, we have lot of guys who doesnot catch the 2% level so with such sketch this is lost by advance with 2% percent drawings.
You have all the data well quantified for the observationnal problem quotation.
For conclusion here is the report of the 30th.
Good hope.
Stanislas-Jean

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#202 azure1961p

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Posted 01 February 2013 - 02:05 PM

Stan a visit to the eye doctor isn't needed nor is any courage. The fact is through virtually all seeing conditions you have the same features showing. Then you report on "bubbles" and such as well as detailed drawings of clouds on the night time side of Venus - a planet of which people rarely if ever see anything in daylight.

Something's contrast transfer, red sensitivety and such can't explain. Seeing thermal signatures in detail on the night side of Venus is one of those.

Pete
 

#203 David Knisely

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Posted 01 February 2013 - 02:16 PM

David Gray posted:

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.
 

#204 David Gray

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Posted 01 February 2013 - 03:19 PM

David Gray posted:

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 questionable by the observer is mentioned as being questionable. 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 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, 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.


You appear to have mis or under-read my post somewhat - (pardon its length)!

Yes with a paint programme Corel Draw /Photopaint in my case you can easily produce a a spurious polar cap effect with the right degree of limb-darkening, also spurious bands edging a painted light zone.

I have seen your paint-effort with Uranus some weeks/months back: showing a rather abrupt edge to the limb-darkeng aginst a rather white central area. This suggests to me too bright an image. Assuming very good seeing there should be no definable edge to the limb-darkening: simply shading off toward centre (look at some of the better Jupiter imagery). I fact so elusive some doubt it is there. To see what I mean look at the texturing settings on WinJupos -check and uncheck the shading box. It is often problematical preseving this effect with scanners - even, at times, applying my better method with the digital camera 'scans' I prefer now - but some success with my more recent efforts. (on ALPO-Japan).

I try to be very deliberate in what I say (hence the length) and only ask that it is read with care. But I do not think I gave an impression of questioning your honesty, or how your eyes behave!
 

#205 stanislas-jean

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Posted 01 February 2013 - 04:47 PM

Sorry for the doctor, but it is laboratory activities with measure machines having resolution grids, color channels, known light levels. There is no medecine at the issue, just a quantified status of your own.
Observing venus in daylight is interresting for light glare limitations. There are best moments for observing also.
Ask David Kni.(he said he has on a last post here)for getting a copy of the book "observing moon, planets and comets" by Dale P Cruikshank and Clark R Chapman, you will find all the necessary explanations, in photometry fields especially for the subject. These are evaluations of the situation of the problem but
before last venus elongation, we were with Mr Put, ccdiste, and the results were remarquably convergent, that is practice and actual data collected.
I am sorry but the visual markings also are more contrasty relatively than on Uranus, during day.
Stanislas-Jean
 

#206 ValeryD

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Posted 07 February 2013 - 02:00 PM

I remain highly skeptical about reports of significant visual detail being routinely seen on that planet. Sorry, but I just don't think there is much of anything there to see.


I am second to that. Despite using 24" Zeiss reflector with excellent optics and in good to calm conditions, I was never able to see any details on Uranus disk, except some smooth brightness decreasing to the edge of the planet disk.

And I am too highly skeptical about all these reports about visibility of distinct details on a dim Uranus 4" disk through 8" SCT.
 

#207 telescopemullet

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Posted 07 February 2013 - 05:45 PM

Post deleted by RLTYS
 

#208 PJ Anway

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Posted 07 February 2013 - 08:23 PM

Could everyone please keep your comments on you own observations and not criticizing the observations of others.

i.e. everyone please keep things positive or the lock cometh.
 

#209 stanislas-jean

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Posted 08 February 2013 - 02:06 AM

Valery, the C8 is not good but excellent.
I had 3 before and was from my use poor to average only.
This one is more than OK. It allowed me to capture 2 times on Mars the high atmosphere electric clouds over the north pole area during march 2012. It allows to see only the fuzzy banding pattern, please refer to the drawings, the refractor achromat being better a little more.
You see the scope is one of the dimension for this subject the observer a second stage and others.
If you consider apos they are very few to allow the capture tiny features of low contrasts. I noted this trouble long time ago. Most of them don't make possible to see feature on Venus or to go deep in low contrasts levels.
The reflectors make this more possible with more accuracy when the optics are excellent.
Now capturing uranus features or venus features depends on your personal equation that can be improved by the observation conditions, especially the lighting conditions because glaring is a great trouble.
Personal equation is working under mesopic conditions that are altered more or less by yourself.
This can be assessed at a laboratory where a staus of your own can be dressed off.
We know the lighting conditions necessary for the optimal conditions. We know the banding sizing of the subject therefore consideing your own status defined you may conlude to some personal abilities.
Not a strict proove but surely something that makes you confortable against the problem that is quoted.
For the moment we get only subjective idea not quoted, not supported by tests, only views experimented or not.
We know now that imagers get features in pure R channel, B for some (the dark collar around the south pole, also catched visually). These channels are visually accessible.
Now, don't know if a fear effect or not, nobody amoung the imager population can state until which contrast level they can capture. Because imaging methods are unproper to measure those contasts levels.
It may be performed long distance tests on calibated targets by imaging in order to study the contrast transfer using a defined scope. For the momment no echo about this kind of approach for testing themselves.
The saga continue but for assessment of the situation it is necessary to practice tests under actual conditions.
R channel can produce around 2% contrast level so few imaged.
Now for conclusion, draw a line of 5% contrast level on light grey paper, this can be done using a word software, and watch this yourself, show this to people in a meeting and make your status result statistics, you will see, well understood the line location being not given at priori.
Stanislas-Jean
 

#210 azure1961p

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Posted 10 February 2013 - 09:54 AM

Valery, the C8 is not good but excellent.
I had 3 before and was from my use poor to average only.
This one is more than OK. It allowed me to capture 2 times on Mars the high atmosphere electric clouds over the north pole area during march 2012. It allows to see only the fuzzy banding pattern, please refer to the drawings, the refractor achromat being better a little more.
You see the scope is one of the dimension for this subject the observer a second stage and others.
If you consider apos they are very few to allow the capture tiny features of low contrasts. I noted this trouble long time ago. Most of them don't make possible to see feature on Venus or to go deep in low contrasts levels.
The reflectors make this more possible with more accuracy when the optics are excellent.
Now capturing uranus features or venus features depends on your personal equation that can be improved n



Yes Stan an excellent Venus scope to be sure . Your sketches of infrared clouds on the night side of Venus was special indeed.

Pete
 

#211 stanislas-jean

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Posted 11 February 2013 - 01:49 AM

Please read carefully the sketch you read for making comments with acurate situation.
There was also lot of tests given through.
Now this is not here the subject, about venus the ashen light never reported in NIR by me, but check also sketches and the few NIR images. Dark features are similar mostly. Thermal activity report of the dark side of venus, pfutt!
Open a new post on that subject I will be.
Stanislas-Jean
 

#212 stanislas-jean

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Posted 15 February 2013 - 12:49 PM

This shall be the last report for Uranus for this present opposition.
In spite of the planet elevation, the observation was not bad but interresting and for collecting what is shown.
Very faint equatorial zone, brightenings at the sun rise limb, clear south polar cap were still accessible.
This was un-expected in fact, observation conditions were good enough and transprency on the sky good also with average good images mostly.
The survey will start again next july or august as possibly, this shall be interresting to see if the banding pattern will change with the solar exposition of the planet..
Stanislas_Jean

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#213 leviathan

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Posted 20 February 2013 - 06:57 AM

Next season hopefully I will also try to see something on Uranus with my 8" SCT and probably 24" observatory cassegrain. Hope to see some details there.
 

#214 stanislas-jean

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Posted 20 February 2013 - 09:29 AM

Don't hesitate to publish what will be performed at the time, the C8 being, we would say, at the margin of possibility.
Stanislas-Jean
 

#215 telescopemullet

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Posted 20 February 2013 - 09:49 AM

The C8 is not at any margin, nor is the 24 based on observations made by posters here that do not bother with fantasy.
 

#216 azure1961p

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Posted 20 February 2013 - 11:28 AM

Actually Pic du Midi had shown nothing as well visually at 1000x.

Pete
 

#217 LivingNDixie

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Posted 20 February 2013 - 12:08 PM

David Gray posted:

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.
 

#218 stanislas-jean

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Posted 20 February 2013 - 02:03 PM

Why do you settle " feature are not there".
Frankly you dont know and not analyse the situation of the problem difficulty, Pete as well, because you see nothing and repeat what the morning star newspaper report.
You may research at the Harvard Library (free access) reference documents about the subject and this is not what the morning star report every day with knowing very few.
Now the pic du midi has nothing to do because catching 2% contrast level is to be aimed and any scope with its aperture will show less level. If you imagine to make strongly better with the aperture increase diameter you will be disapointed by the gain got. Try in first to catch those levels without a scope under similar lighting conditions this shall be a beginning.
You dont visit an optical laboratory to see where you are actually with your eyes capabilities, but you are sure, of what.
You dont test your scopes and never assess a problem as it is, canali are in your mind.
Frankly since the beginning of this forum you strictly bring nothing but just claim for claiming.
I have something else to perform and prepare for future and left here, not loosing time.
Staanislas-Jean
 

#219 telescopemullet

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Posted 20 February 2013 - 03:28 PM

Same old song and dance...
 

#220 starrancher

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Posted 20 February 2013 - 04:13 PM

Same old song and dance...


:band: :yay: :yay: :yay: :yay: :yay: :banjodance: :thewave: :thewave: :thewave: :thewave: :rimshot: :gve: :whee: :hamsterdance: :hamsterdance: :hamsterdance: :thankyou: :rofl2: :choochoo: :elephdance: :elephdance: :elephdance: :salute:
 

#221 telescopemullet

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Posted 20 February 2013 - 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.
 

#222 ZielkeNightsky

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Posted 20 February 2013 - 06:13 PM

Moderators, please. - like children.
 

#223 David Knisely

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Posted 20 February 2013 - 06:47 PM

David Gray posted:

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.
 

#224 telescopemullet

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Posted 20 February 2013 - 08:59 PM

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?
 

#225 azure1961p

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Posted 20 February 2013 - 10:31 PM

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
 






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