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#1 Brian Albin

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Posted 13 March 2013 - 10:26 PM

I saw a tremendous amount of the Ashen Light a few minutes ago, 13 March 2013, just before moon set.
Through binoculars I could see about one third of the Lunar disc well lit, even though the properly lit part was only a slender sliver.
I have never seen so much or so obvious ash light before. Is a cause known why this light should be more prominent on one night than on another?
 

#2 azure1961p

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Posted 13 March 2013 - 10:35 PM

That's not the ashen light, its earthshine - our beaming sun drenched planet illuminating lunar nighttime that faces us.

The ashen light of Venus is an optical illusion created by the eye/brain filling in an area the cusps of a crescent infer should be there.

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#3 photonovore

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Posted 14 March 2013 - 10:16 AM

The ashen light of Venus is an optical illusion created by the eye/brain filling in an area the cusps of a crescent infer should be there.

Pete


That is *one* theory.... ;) Others, more likely IMO, are 1)static electrical discharges in the atmosphere (lightning), 2)phenom similar to earth auroras 3)a glow producing reaction of UV with CO2 molecules. And 4---an as yet unknown mechanism.

Although the eye can play it's share of tricks, it is, I believe, unwise to assign observer imagination as a most likely cause by default when something unusual is observed. Doing so was once de rigueur but I think this default has gained needed nuance since, considering the 'spokes of Saturn's rings' (once declared imaginary, now known as real) or *some* lunar TLP varieties (flashes), again once dismissed as imaginary but now recognized as meteor strikes. ETC.
 

#4 Edward E

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Posted 14 March 2013 - 10:18 AM

The Ashen light of Venus is not an optical illusion but a real phenomena of our sister planet. Though not fully understood it is similar to airglow on Earth but at a greater scale. The best evidence so far are spectroscopic observations of the phenomena made by Russian Astronomers back in the late 70s plus lots of documentation by the late Sir Patrick Moore and team over at least 40+ years.

I have seen the Ashen light once back in the late 70s. It looks very much like "Earthshine" on the Moon, just not as much blue hues, as the name implies it's an "Ashen" or light gray color. At the time Venus was in a "large" crescent phase. I have seen Venus in this phase many time since but the shadowed portion has remained invisible.
 

#5 azure1961p

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Posted 14 March 2013 - 11:21 PM


The ashen light of Venus is an optical illusion created by the eye/brain filling in an area the cusps of a crescent infer should be there.

Pete


That is *one* theory.... ;) Others, more likely IMO, are 1)static electrical discharges in the atmosphere (lightning), 2)phenom similar to earth auroras 3)a glow producing reaction of UV with CO2 molecules. And 4---an as yet unknown mechanism.

Although the eye can play it's share of tricks, it is, I believe, unwise to assign observer imagination as a most likely cause by default when something unusual is observed. Doing so was once de rigueur but I think this default has gained needed nuance since, considering the 'spokes of Saturn's rings' (once declared imaginary, now known as real) or *some* lunar TLP varieties (flashes), again once dismissed as imaginary but now recognized as meteor strikes. ETC.


There is zero evidence that aside from infrared light that anything is visible visually here. You don't need to drain the Locke to debunk the monster.
The fact that absurdly small refractors had shown this effect while a 60" didn't and other peculiar discrepancies only go to support the fact that its an eye brain illusion. Moreover you don't even need Venus to see it as its fairly easy to reproduce the effect artificially since it doesn't reside in reality.
Sure there's theories a plenty but its all pretty thin . Not that these phenomena don't exist, but that they are seen visually is an impossibility.
Back in the 80s maybe, or early 90s Sky and Tel had a revealing article on the quantification of ashen light accounts that often defied expectations for when it should have shown in great scopes but instead revealed in small aperture. I couldn't think of a bigger myth in contemporary visual astronomy . There is absolutely nothing visual to be seen on the night side if Venus ever UNLESS you have a CCD and proper filter.

I was wrong in saying you don't need to drain the lock. Modern CCD imaging has infact done this and their is no wiggle room for visual sighting justification . The retina simply isn't sensitive to infrared.

That this Ashen myth persists is peculiar. Again, is there atmospheric activity and so on - absolutely -I have little doubt. But I have full confidence no human being as ever or will ever see this *light*.

Pete
 

#6 Rick Woods

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Posted 14 March 2013 - 11:51 PM

If it's not there, how come it's there?
 

#7 buddyjesus

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Posted 15 March 2013 - 12:40 AM

I have abundant evidence supporting my case that the ashen lights is not worthy of discussion in the lunar forum.
 

#8 azure1961p

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Posted 15 March 2013 - 06:08 AM

Well I'm not going go argue the point we have our views - the least if which as Mr, Jesus points out , this is a lunar forum afterall! Thanks take care!!! And Rick I would submit to you that this Ashen view has already been discredited by Barsoomins as well as the local lunar chickens. Yes I know Rick - ouch.



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#9 photonovore

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Posted 15 March 2013 - 11:51 AM



The fact that absurdly small refractors had shown this effect while a 60" didn't and other peculiar discrepancies only go to support the fact that its an eye brain illusion.

Sure there's theories a plenty but its all pretty thin . Not that these phenomena don't exist, but that they are seen visually is an impossibility.

Back in the 80s maybe, or early 90s Sky and Tel had a revealing article on the quantification of ashen light accounts that often defied expectations for when it should have shown in great scopes but instead revealed in small aperture. I couldn't think of a bigger myth in contemporary visual astronomy .

Modern CCD imaging has infact done this and their is no wiggle room for visual sighting justification . The retina simply isn't sensitive to infrared.

That this Ashen myth persists is peculiar. Again, is there atmospheric activity and so on - absolutely -I have little doubt. But I have full confidence no human being as ever or will ever see this *light*.

Pete


Ok, first, that is exactly the same argument used to "disprove" the reality of "spokes" in Saturn's rings.

Second, "thin" doesn't translate to "impossible"...rather it translates to "not fully understood" and or "improbable".

Third, 80's and 90's? Things change and those who make declarations of certainty risk eating crow--especially in planetary science (which includes the Moon). Take Venusian lightning for example... In the late 90's, based on Cassini data on it's flyby of Venus on it's way to Saturn, a team led by Gurnett of the U of Iowa concluded "If lightning exists in the Venusian atmosphere," the team concludes, "it is either extremely rare or very different from terrestrial lightning." But...lol...more recently we have this from Nasa: "In addition to all the pressure and heat, we can confirm there is lightning on Venus -- maybe even more activity than there is here on Earth," said Christopher Russell, a NASA-sponsored scientist on Venus Express. In the same report (2007) they declared this lightning "unique from Earth" because there was no water vapor involved...except now there apparently *is* (ESA et al findings since).

Fourth, have CCD's yet caught the spokes in Saturn's rings? I forget, but am curious...

Fifth, the phenom remains "controversial" because of an extensive observational record and a generalized lack of professional scientific interest in resolving what is really a purely observational controversy. *But* what the "ashen light" issue has done for Venusian science is neatly summarized by Lisa Riley:
"There have been many questions as to the relevance of any findings regarding Venus' ashen light. Many argue that it offers no known practical applications. But, scientists conclude that continued research is interesting for its own sake, at least partly because it explains an old astronomical mystery. By observing the motion of glowing air in the Venusian atmosphere, scientists can better understand the dynamics of that atmosphere, and those observations might shed light on the dynamics of Earth's atmosphere. Moreover, scientists hope to refine observing techniques used to study this atmospheric phenomenon to assist in future studies of other planets that orbit distant stars. As such, the scientific exploration of Venus' "ashen light" will continue."

Anyway, you could well be right...may well be an illusion and a myth after all. But I am not predisposed, *personally* to slam doors shut on any phenom when the current state of research of this planet's atmosphere is in such a dynamic phase --and as it presently promises to remain for some time...

BTW, while I was browsing around the net looking into this, i found a number of references in the (scientific) literature of "ashen light" referring to *earthshine" of the Moon. So, it may not be as plainly incorrect of a usage of that term as it appeared at first blush. :)
 

#10 Brian Albin

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Posted 15 March 2013 - 02:52 PM

So, Is a cause known why this light should be more prominent on the moon one night than on another?
I could see craters all over a broad expanse covering the lower one third of the disc with only 6x30 binoculars. It is far more than I have ever seen before. Because of the cloudiness of western Oregon I have not seen many examples of this ash light, but I am 53 years old and have looked up to the moon what seems many times to me through the years.
I can not think what could make this light have either more extensive coverage or greater intensity in one instance than in others.


Mardi said:
"While I was browsing around the net looking into this, I found a number of references in the (scientific) literature of 'ashen light' referring to 'earthshine' of the Moon."

Thank you, Mardi. That is where I had learned this word - in Astronomy textbooks.
 

#11 Rick Woods

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Posted 15 March 2013 - 03:11 PM

Brian,

Could it be that the light is brighter when the face of the Earth facing the moon is more highly reflective (cloud cover, ocean, etc)? What hemisphere and meteorological conditions were facing the Moon at that time? Maybe it's possible to find out.
 

#12 azure1961p

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Posted 15 March 2013 - 05:22 PM


Ok, first, that is exactly the same argument used to "disprove" the reality of "spokes" in Saturn's rings.
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Actually its not the same argument at all. The best observers with large aperture saw these features. This is in line with a real phenomena as opposed to saying Steve Omeara saw the spikes with an 3" refractor while Clyde Tombaugh failed with a 16". It's not true of course Clyde did infact see it with the 16 and Omears with great aperture/scope which threshold observations dictate.

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Second,
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That your counting here is humorous but ill move with the step...
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"thin" doesn't translate to "impossible"...rather it translates to "not fully understood" and or "improbable".

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And since there are no absolutes in life so goes this hiding space for erroneous observation to call a home.
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Third, 80's and 90's? Things change and those who make declarations of certainty risk eating crow--especially in planetary science (which includes the Moon).

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No crow here snd that it made the magazine is testament to not only its historic rekevance but persistence of illusion though in fairness to sky, they were more liberal in interpretation (pre CCD too so...)
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Take Venusian lightning for example... In the late 90's, based on Cassini data on it's flyby of Venus on it's way to Saturn, a team led by Gurnett of the U of Iowa concluded "If lightning exists in the Venusian atmosphere," the team concludes, "it is either extremely rare or very different from terrestrial lightning." But...lol...more recently we have this from Nasa: "In addition to all the pressure and heat, we can confirm there is lightning on Venus -- maybe even more activity than there is here on Earth," said Christopher Russell, a NASA-sponsored scientist on Venus Express. In the same report (2007) they declared this lightning "unique from Earth" because there was no water vapor involved...except now there apparently *is* (ESA et al findings since).

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Interesting but doesn't apply to what's reported visually. Visual reports offer no flashing fluctuations but more over its be highly unlikely an entire hemisphere is experiencing a simulataneous lightning storm of unwavering voltage with the steadiness if a fluorescent light however dim.

Does it have lightning? Ill bet it does. Not full time globally fluorescing with bolts of uniform output.
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Fourth, have CCD's yet caught the spokes in Saturn's rings? I forget, but am curious...
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CCDs like even the one I own have routinely recorded the spokes. Always, no but several times per apparition.
Usually with 14" sperure and larger . Why the folks here on CN even have made little animates showing the arcs whopping around on the ring structure. Believe me Mardi - I'd ANYONE can see it visually than the CCD ought to handedly acquire it as well. Infrared doesn't count.
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Fifth

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More counting????????
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, the phenom remains "controversial" because of an extensive observational record and a generalized lack of professional scientific interest in resolving what is really a purely observational controversy. *But* what the "ashen light" issue has done for Venusian science is neatly summarized by Lisa Riley:
"There have been many questions as to the relevance of any findings regarding Venus' ashen light. Many argue that it offers no known practical applications. But, scientists conclude that continued research is interesting for its own sake, at least partly because it explains an old astronomical mystery. By observing the motion of glowing air in the Venusian atmosphere, scientists can better understand the dynamics of that atmosphere, and those observations might shed light on the dynamics of Earth's atmosphere. Moreover, scientists hope to refine observing techniques used to study this atmospheric phenomenon to assist in future studies of other planets that orbit distant stars. As such, the scientific exploration of Venus' "ashen light" will continue."

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Mardi / the loche is empty - there's no monster.
/--------
Anyway, you could well be right...may well be an illusion and a myth after all.
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Aaaaaahhhhhh

But I am not predisposed, *personally* to slam doors


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its not slammed . its slightly ajar pending real supporting data in vidusl wavelengrhs.
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shut on any phenom when the current state of research of this planet's atmosphere is in such a dynamic phase --and as it presently promises to remain for some time...

BTW, while I was browsing around the net looking into this, i found a number of references in the (scientific) literature of "ashen light" referring to *earthshine" of the Moon. So, it may not be as plainly incorrect of a usage of that term as it appeared at first blush. :)

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Well it'd belong there. An apt description if a real external world phenomenon.

In answer to questioning the moons variable nature if its own earthshine, I think the variability perceived is primarily transparency/light pollution related with our sky's. that our own meteorilogical causes of extra clouds in a hemisphere wide pattern(s) is compelling however.

Pete
 

#13 photonovore

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Posted 16 March 2013 - 11:46 AM

Pete, you may not remember how controversial (the reality of) spokes in saturn's rings once were but i certainly do. The first time they were imaged was by Voyager back in the early 80's, but *prior* to that the dynamism of the ring system was greatly underestimated by then current science and the reportage of this phenom was regularly written off as "illusory".

The "counting" is per point you made to avoid a big quote mess (such as i am dealing with now... ;) )

CCD's have a *huge* problem with dynamic range. The human eye remains vastly superior to current CCD tech in this regard. As Venusian ashen light by it's nature is a very high dynamic range phenom, it is actually not that improbable that it may be beyond the CCD's ability to capture in the visual waveband.

"Not slammed"? Ok, guess i misunderstood the (i thought) unambiguous nature of the term "myth" and the declarative nature of your statement: "i have full confidence no human being has ever or will ever see this *light*." Language of certainty just bugs me when used in conjunction with planetary science...an infant field where new data _constantly_ conflicts with scientific preconceptions. My goodness, hardly a week goes by where i don't read a phrase like "researchers surprised by new data" in a press release! Planetary science is no place for dogmatism, that's certain.

Optical illusion being a minor interest of mine, i know full well the limitations of human vision. But I also would note that most optical illusions are not *episodic* or population sensitive given the same conditions...iow, pretty much *everyone* sees the Lunar illusion whenever the Moon lies near the horizon. Probably one of the stronger arguments against the illusory aspect of Venusian ashen light therefore is that it is *not* seen by virtually everyone whenever Venus is at a narrow crescent phase per-inferior conjunction (most common time for such to be observed)--but in fact far from it, being highly episodic in occurrence/observation.




The intensity of lunar earthshine is due to the variability of the reflectivity of the illuminated portion of the earth as seen from the Lunar perspective. This variation in reflectivity is primarily dependent upon the percentage of highly reflective cloud cover/snow/ice directing sunlight back to the Moon and has virtually zero to do with artificial light (light pollution) from the nightside of the planet. (ref:http://yly-mac.gps.c...ef/Goode_01.pdf )
 

#14 azure1961p

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Posted 16 March 2013 - 05:21 PM

Mardi,

Im through with the subject. Its a lunar forum to begin with so this doesnt really apply here anyway. Theres nothing compelling here for me to reconsider and itemized nitpicking is something I dont want to get into.

Thanks for your comments.

Pete
 

#15 photonovore

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Posted 17 March 2013 - 11:00 PM

Sorry you see my interaction as "nitpicking". From my perspective, i was merely trying to expand your viewpoint to include other considerations--which go to why this phenomenon is still considered as an unresolved phenomenon by science.
 

#16 THEPLOUGH

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Posted 18 March 2013 - 06:34 AM

Sorry guys but enough is enough...
 






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