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Ashen Light - Redux

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#1 Rick Woods

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Posted 18 March 2013 - 05:18 PM

There was a thread going in the Lunar forum that got sidetracked to the Ashen Light of Venus (a subject much more suited to this forum). It was shut down, but it was actually just getting very interesting. The primary participants were Mardi (Photonovore) and Pete (Azure1961), who had a pretty lively debate going on.

I was sort of hoping we could take it up again here. Both participants are articulate, and hopefully things would remain civil and productive. Pete does not feel the Ashen Light is a real Venusian phenomenon; Mardi raised many questions about that stance, and suggests that the issue is far from resolved; and one poster noted seeing the Light personally.

Can we continue from there without anyone getting irate? We all just want to learn from each other, after all. Many's the time I've had a long-held belief changed by learning a serendipitous new fact.

#2 azure1961p

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Posted 18 March 2013 - 06:08 PM

Lol, you're a sadist astronomer!!!

Pete

#3 buddyjesus

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Posted 18 March 2013 - 06:25 PM

haha

I think we can all agree that the phenomenon exists. It is the location of the phenomenon that is disputed(on Venus or in our brains.) I wish I had a scope with less CA so that I would have a chance at seeing it well.

#4 ROBERT FREE

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Posted 18 March 2013 - 07:01 PM

ive seen it a few times myself over the years,but sometimes i think the brain causes some of it ,but patrick moore has also stated he an other good astronomers saw that as well.in daylight when the crescent is real big i saw it a few times over the years and the surface area was definitely darker on venus opposite the crescent.

#5 ROBERT FREE

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Posted 18 March 2013 - 07:06 PM

also at half phase i definitely noticed a slight darkening at the the terminator many times,but that can possibly be due to contrast effects or scattered light.a few of my friends also said they saw the ashen light at the gibbous phase.

#6 Rick Woods

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Posted 18 March 2013 - 07:16 PM

Lol, you're a sadist astronomer!!!


Maybe. But the subject interests me, and it deserves objective discussion. This is the best place I know of to get intelligent opinions. (As well as goofy ones.)

#7 ROBERT FREE

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Posted 18 March 2013 - 07:22 PM

well i would like only intelligent ones,an patrick moore as you well know did extensive research on this subject an had individual attestation from other astronomers viewing independently.in the seventies an early 80ties i spend a ton of time on venus an have saw some unusual activity near the cusps an real bright circles unmistaken but so far as the ashen light there is definitely a darkening notiecable in clear skies an in daylight just like our moon with earthshine,now what the causes are is debatable i agree.

#8 azure1961p

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Posted 18 March 2013 - 08:09 PM

Im going to sit this one out Rick. I have my own views, beyond that it just gets to negative to assert a negative opinion even when im positive in my negativity. It is a beautiful planet and one Sheehan mentions with heartfelt fondness { yesim still glowing from that book while waiting on my delayed shipment of his mars book}.

Pete

#9 ROBERT FREE

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Posted 18 March 2013 - 08:33 PM

do i think the ashen light is real.probably not, as venus itself is covered with clouds an its high reflectivity is most likely the cause.we rarely get to see the surface an there is a bunch of activity going on all the time.

#10 Rick Woods

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Posted 19 March 2013 - 01:25 AM

Im going to sit this one out Rick. I have my own views, beyond that it just gets to negative to assert a negative opinion even when im positive in my negativity. It is a beautiful planet and one Sheehan mentions with heartfelt fondness { yesim still glowing from that book while waiting on my delayed shipment of his mars book}.

Pete


Well, looks like Mardi is, too. Too bad. I would have liked to know what evidence you've seen to make you so positive it's an illusion.
Healthy debate and comparison of information can benefit everyone, if they'll listen to each other.

#11 stanislas-jean

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Posted 19 March 2013 - 04:27 AM

Regarding the Venus ashen light here is a link where a report can be found about.
http://hebergement-p...mypdf.php?n=158
Hope it is functionning.
All the references collected in the table sheet are drawings issued on the alpo japanese site
http://alpo-j.asahik...atest/Venus.htm

it can be discussed the visibility of the this strange light eg the fact this was not collected by ccd but in fact what can be argued is the fact that the light levels (crescent and ashen light) are quite different sothat light glare becomes a main topic on the ccd chipset even with the use of an occulting bar.
At final this remains controversial and very strange.
Contracditory also as between observers quite different observations are collected but what it must be highlighted is the fact that episodic observation are unfruitful and a daily basis survey has to be performed for sure.
Good read, I donot pretend this a true overall status but it was tried lot of kind of observations in order to understand what is happening.
Light levels needs to be quantified by parallel investigations.
Stanislas-Jean

#12 azure1961p

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Posted 19 March 2013 - 06:34 AM

The evidence to me is that the ashen light effect can be reproduced artificially. Same thing that produces the Terby Whitespot on Saturn for example in that its an illusion of contrasts and the brain manufacturing information through suggestion. That and the only thing that could light up the night side would be in the infrared. A sustaining global lightening storm with a steady unchanging output or full hemisphere aurora is unlikely to impossible. These are my claims. Also its important to consider that CCD images in visible light are at least as good as the eye in many cases and hard proof would have surfaced by now - and Id applaud it. That Mardi wasn't even aware of CCD sensitivety good enough to routinely image the spokes on Saturn casts doubt in my mind that she isnt realuzibg how thorough these instruments are today and as a result how handedly something as common as the Ashen Light would have been captured. strong claims by individuals even with 80mm refractors and again frequently enough, would certainly have landed such a feature through a C14 with a CCD by now - or any common and effective lunar planetary imaging system. This is an immense hurtle to overcome in arguing in favor of the ashen light and the reports through any number of sized instruments.
If such a thing existed you'd have these beautifully detailed, albeit, unbelievably so , images coming from guys like Damian and such. Instead - what we've got is modern amateur planetary imagers making beautiful and detail nighttime hemisphere images of glows in the infrared - an impossible feat for any human to make visually. The trouble with the artificial ashen light model is that its subtle enough that if someone wants to ignore it to support a belief its possible.

I'm not saying anyone's nuts for seeing it, Im saying its an artifact of the eye brain interpretation.

Pete

#13 stanislas-jean

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Posted 19 March 2013 - 07:13 AM

Why not.
What is the Terby white spot on saturn? If you have some data about.
However regarding the report on reference you see many tests were performed also.
The use of an occulting bar (that occults all the cresent) set on the planet by a second observer and then observed whitout a reset on the whole image. Believe me the dark side appeared with a low light often with a coppered color appearance sometimes, reported by past observers also.
There is also the dark markings reported that suit also with some few ccd images.
IR images: frankly under 1µm wavelength this cannot be a thermal effect and a little also above this wavelength.
It is impossible to get light from the ground with the ground temperature given in the literature about (450°C).
This could be explanained if some chemical reaction is occuring under specific conditions (pressure, some gaz presence) that locally involve an higher physical temperature for being thermal. But which one?
Now the fact that ccd for the moment doesnot capture this dark side light amount is disagread by the light glare of the light crescent. What is obvious can be that the ccd chipset after an exposure time would reach a certain threeshold and therefore if the AL is existing its light level would be under the level of this threeshold reached. Nothing else. This threeshold is not noted.
Anyway, this should be developped and the observations needs to be more frequent.
The 50mm refractor observations are interresting on the fact that the light levels has moved sothat on a dawn light (the sky becoming dark) it was noted like a darker hole for the dark side on a date and for an other observation the dark side was seen lighted faintly. Observing with higher apertures the dark hole effect was never seen but a lighted dark side, almost at the similar moments.
That make me thinking this is a problem of light level accessibility only not depending on a specific colour channel vision.
But again, no enough data for a straight conclusion here.
Stanislas-Jean

#14 ROBERT FREE

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Posted 19 March 2013 - 08:42 AM

there is no doubt that the ashen light is seen,ive had so many reports from other amatuers an many real good observers an i also have seen it, BUT we will never know if does exist or what causes it.but there are other strange phenomenon like the real sudden bright spots that have popped up on occasions an these i think are real coming from what i dont know.many times i thought i saw a small break in the clouds during those white spot appearences,an at that time i was using a 12 1/2 inch f-8 reflector an high quality galaxy mirror.i had too stand on a ladder as well but it gave fantastic images so i know what i saw an others did too.im more interested in what happens on venus even if its only a glimpse sometimes, venus appears very active and maybe one day we will go there and use some probes or land but i doubt it in my lifetime.

#15 stanislas-jean

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Posted 19 March 2013 - 08:59 AM

Reason why daily basis observations are needed.
Personally I noted some fluctuation of the AL level on a period. This is strange.
But even the AL was reported by observers even well known, I guess you see the below sketch for being sure of the AL occurence.
This is a processus a little hard for ourselves but this helps for being more confortable with the situation.
Stanislas-Jean

Attached Files



#16 stanislas-jean

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Posted 19 March 2013 - 09:07 AM

You see the unknown settlement of the planet into the eyepiece equipped with an occulting bar by a second observer, is interresting to perform. The 1st observer will see or not something then if seen move the occulting bar to see if the crescent is in correspondance.
Hard.
The second sketch approaches the question of the light levels and is a support for the processus of light difference levels to capture. This is a trial because frankly I donot know if the light ratio of 1000 between the crescent and the dark side is adequate.
This is may a way to the solution.
Stanislas-Jean

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#17 ROBERT FREE

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Posted 19 March 2013 - 10:57 AM

in mercurys case its most likely impossible to see any dark side because of the dimness of the planet in its crescent phase.even today its very thin phase illumination is 0.236 and its disk size around 9.5 at 1.0 magnitude according to the data an cannot be seen but in about 3 days or so at 9" disk size an say 0.7 mag is about the limit to see the thin crescent but not thin enough for any ashen light.but like i said before i doubt as well if any ashen light truly exists an is most likely an optical illusion or high reflective scattered light. an btw JEAN that was very informative an thx.

#18 stanislas-jean

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Posted 19 March 2013 - 12:39 PM

At final the japanese Alpo published the report.
Here is
http://alpo-j.asahik...13/v130318r.pdf
the drawings are on the same topics.
Hope this is an help and easier.
Stanislas_Jean

#19 azure1961p

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Posted 19 March 2013 - 02:02 PM

BUT we will never know if does exist or what causes .


Good news. We know its imaginary because it isn't recordable with the detectors of current day which wod have no trouble imaging such a contrast intensity. It'd be pedestrian. There's no overreaching mystifying deceptor - it doesn't exist.

There. Now you are truly Free.

Pete

#20 buddyjesus

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Posted 19 March 2013 - 04:45 PM

more food for thought. http://www.universet...-ashen-light-2/

"The Keck 1 telescope on Hawaii reported seeing a subtle green glow and suggested it could be produced as ultraviolet light from the Sun splits molecules of carbon dioxide, known to be common in Venus’ atmosphere, into carbon monoxide and oxygen, but the green light emitted as oxygen recombines to form O2 is thought too faint to explain the effect. Another more likely theory is that multiple lightning strikes are illuminating Venus’ skies. Though the Cassini spacecraft flew by Venus twice on it’s voyage to Saturn and failed to detect the high frequency radio noise we associate with thunderstorms on Earth, in 2007 Venus Express did detect low frequency ‘whistler waves’ that can also result from lightning. It could also be the Venusian equivalent of aurorae."

Read more: http://www.universet...ht-2/#ixzz2O...


my money is the keck telescope had a camera on it and not an eyepiece. My money is on it not occuring on Venus, but monitoring should be done any way. what is the harm in amateurs looking? I think it is also common for people to view the polar cusps and think it is ashen light.

#21 stanislas-jean

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Posted 20 March 2013 - 03:41 AM

Interresting Buddy, this bring a lot on the subject.
Is there something was performed on Mercury from your informations with the Keck or some other big guns?
It is strange that on Mercury, from my observations, nothing such was reported. It is harder to observe Mercury but the reports are the reports.
I agree with you, more observationnal data are needed for making a straight conclusion.
Pete, the fact that with ccd chipset, if with 1s, 10s, 30s etc exposure time nothing is collected, this doesnot mean that AL is not existing but again that a certain amount of light cannot be captured with such exposure. Beyond 30s, light glare is very present and disturbing so that the capture method has to be very expected acurate.
Also the duality eye-ccd properties cannot be straightforward so easily.
Is there somebody who knows where to find ephemeris of the solar wind reaching planets (here for Venus)? or this is confidential.
Stanislas-Jean

#22 azure1961p

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Posted 20 March 2013 - 01:08 PM

You need to try some imaging Stan there is no hiding place with a DMK DBK Flea3 Toucam or the like. Your assumptions are more in line with Tri-X.

Pete

#23 stanislas-jean

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Posted 20 March 2013 - 01:55 PM

Just 2 or may be 3 time more sensitive than mine in NIR.
Stanislas-Jean

#24 Rick Woods

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Posted 21 March 2013 - 02:03 AM

there is no hiding place with a DMK DBK Flea3 Toucam or the like.


What on Earth makes you think that, Pete?

#25 stanislas-jean

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Posted 21 March 2013 - 03:54 AM

The question of ccd collection is a sensitive point for sure.
However considering the document brought by Buddy, I noted a ratio cresecent dark side of 10 000 (means 10 magnitude difference probably on the O3 colour channel).
This ratio would involve some exposure times for collecting something of 10 minuts.
Having done some trials with a sony 098BL chipset, beyond 30sec this becomes hard to not be annoyed by the light glare even with the occulting bar use of D3 density.
So from my opinion this should not be the subject on this forum to say
this is an illusion
this is lightning
this thermal
this is water vapor dissociation
etc...
but if each is existing which light level could be expected and therefore to discuss which capture method can be undertaken.
Frankly imaging is not only a fact to set a chipset and to practice exposures (this is the prior first step of a method in order to start an apraisal only).
The links brought by Buddy are interresting because some light levels are expected and this goes on this approach at final.
If somebody wants to pursiue on that approach, please goahead, I will follow with open mind in order to built some assessment methods that can be undertaken for the next Venus conjunctions.
Matter of a forum!
Stanislas-Jean






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