[Chaos-l] Skywatching canceled

[john.6.miller at gsk.com]

I have read that there is a natural luminescense or "airglow" that arises 
from air molecules being excited by the sun during daylight hours and then 
slowly decaying with a weak emission of visible light that persists 
throughout the night.  However, I don't know if the intensity of this 
phenomenon is sufficient to account for the observed sky brightness you 
guys are talking about.  See: http://en.wikipedia.org/wiki/Sky_brightness.

John Miller





"Mark South" <md_south at mac.com> 
Sent by: chaos-l-bounces at rtpnet.org
21-Sep-2009 07:48
 
To
"Michael Hrivnak" <mhrivnak at hrivnak.org>
cc
"CHAOS" <chaos-l at rtpnet.org>
Subject
Re: [Chaos-l] Skywatching canceled






I suspect that a truly dark place is somerwhere like austrailia or 
antartica.
Mark

Sent from my cell phone

On Sep 20, 2009, at 9:46 PM, Michael Hrivnak <mhrivnak at hrivnak.org> 
wrote:

> You mentioned that the weather wasn't great a lot of the time.  When 
> the sky
> was completely clouded over, were the clouds lit up at all, or was 
> the sky
> black?  My experience at Almost Heaven was that the sky was actually 
> a bit
> brighter when it was completely cloudy.  That tells me that even in 
> a very
> dark place, there is some light pollution reflecting off of the 
> clouds, and thus
> the same light brightens a clear sky at least a little.
>
> Although, I suspect that stars which are too faint for us to resolve
> individually with the naked eye could collectively cause the whole 
> sky to seem
> less-than-black.  It would be interesting to look at a part of the 
> sky with
> the least number of stars, and compare its blackness to other parts.
>
> Michael
>
> On Sunday 20 September 2009 02:32:09 pm Mark South wrote:
>> I know this is slightly off topic but I had a question
>>
>> I noticed at okie Tex one of the darkest star parties in the us that
>> the sky as never truly black.. sort of how it looks at the
>> planetarium.  Why is that?  I think it was quite clear but the sky
>> still was grayish.  Is it possible to find a black sky with stars on
>> earth with an atmosphere and light adaptation.  Greg Dillon theorized
>> that it is truly darker than we realize but he thinks the stars light
>> the sky up some.  Has anyone ever thought of this or been to a truly
>> black sky?
>>
>> Mark
>>
>> Sent from my cell phone
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