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Venus 'Ashen Light' seen!

  • Keith g
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19 years 11 months ago #2746 by Keith g
Venus 'Ashen Light' seen! was created by Keith g
Speaking of Venus - On Saturday night (May 8th 2004) at about 9.30pm local time (2030Hrs UT)I could have sworn - in fact I did see the unusual sight of 'Ashen Light' - the sight of the unlit side of Venus.

I was using my 8" SCT at Mag x100 when I easily saw what I could only describe as a 40 arcsecond size disk/ball hanging in my field of view. The 'Darkside' of Venus was clearly visible as a dark brown coloured sphere, directly visible, not even hard to trace. I did'nt even need to use averted vision, the whole planet was clearly traceable, I could even make out the curve of the unlit portion
of the planet, I did'nt use any filters. The sky was still quite bright as the sun set at about 9:10pm. I choose this time as no to let the
light from the bright side of Venus to swamp the view.

I had to call my wife out to have a look, not saying anything, her reaction - OH! the Moon, it looks lovely - that's the earthshine is'nt it!!!!! Well - Independent observer No.1!

So, my question - Is this a rare sighting/or is this to be expected when Venus is this close?? Has anyone else seen this?
This was the 1st time I've ever seen this in 10 years of observing!
Keith..

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19 years 11 months ago #2747 by albertw
Replied by albertw on topic Re: Venus 'Ashen Light' seen!
Was at a talk by Prof. Fred Taylor from Oxford, and he mentioned that the Ashen light may be caused by the surface ov Venus being so hot that it glows, and its this glow that lights up the clouds.

Not so long ago this was thought not to exist!

Cheers,
~Al

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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  • Keith g
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19 years 11 months ago #2748 by Keith g
Replied by Keith g on topic Re:
Definitely seen it!, just like a 3 day old moon - just seemed further away and no craters :D
Keith..

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19 years 11 months ago #2749 by dave_lillis
Replied by dave_lillis on topic Re: Venus 'Ashen Light' seen!
Keith/Albert,
I was out observing Venus on the 7th of May between 10 and 10.30 and I thought I was seeing some sort of optical/mind illusion,as if I could make out the rest of the shape of Venus. I thought that the scientific community had dismissed this phenomena ???
Did the latest set of probes to Venus over ther last 10 years all but dismiss the Ashen lights ???

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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19 years 11 months ago #2752 by galwayskywatchers
Replied by galwayskywatchers on topic caution- may not be ashen light
Some people are saying they have seen the Ashen Light of Venus before and after sunset. if you check the March 2001 edition of Sky and Telescope P101, it says the the ashen light of Venus can ONLY be seen well after sunset, what ye ae seeing is an optical illusion where by its disk appears slightly darker as the eye completes the circle of the crescent. In a truly dark sky the brilliance of venus will test any optical system, some refractors will show venus sorrounded by a violet fringe(false colour), they say the use of an occulting bar may help in seeing the ashen light by hiding the crecents glare.As the crescent really begins to thin look for an extension of the horns beyond the 180 degrees sector to which they are usually confined. The thick athmosphere actually reflects and channels light beyond the sunlit hemisphere

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19 years 11 months ago #2754 by albertw
Replied by albertw on topic Re: Venus 'Ashen Light' seen!
Hi,

Not sure about the evidence from recent observations Dave, but this paper from 1992 give a nice overview of the ashen light at various wavelengths. Appears to be written with amateurs in mind.

adsbit.harvard.edu/cgi-bin/nph-iarticle_...=1992raa..proc...43C

Cheers,
~Al

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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