[Chaos-l] Skywatching canceled

[Mark South]

Thanks for all the great info!
Mark

Sent from my cell phone

On Sep 21, 2009, at 9:27 AM, Robert Nielsen <robertnielsen at nc.rr.com>  
wrote:

> I usually think the background glow is because of moisture in the  
> air ... reflecting WHATEVER light there happens to be (moon below  
> the horizon, campfires, streetlights).   Has anyone noticed a  
> difference based on humidity or temperature?   For me, the night  
> skies are usually more "contrasty" than summer skies ... which I  
> think means the same thing you noted, Mark.
>
> Robert
>
> Mark South wrote:
>> Thanks John!
>> This is a good article to explain the phenomena-- a combo of  
>> airglow, indirect scattering of sunlight, stars, minimal light  
>> pollution, and twilight.  I know it was dark there with no light  
>> domes, but seeing gray sky as well as being able to walk around  
>> made me think... is space the only way to get that "Morehead  
>> Planetarium" black sky??
>> Mark
>>
>> On Sep 21, 2009, at 8:45 AM, john.6.miller at gsk.com <mailto:john.6.miller at gsk.com 
>> > wrote:
>>
>>>
>>> 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 <mailto:md_south at mac.com>>*
>>> Sent by: chaos-l-bounces at rtpnet.org <mailto:chaos-l-bounces at rtpnet.org 
>>> >
>>>
>>> 21-Sep-2009 07:48
>>>
>>>           To
>>>    "Michael Hrivnak" <mhrivnak at hrivnak.org <mailto:mhrivnak at hrivnak.org 
>>> >>
>>> cc
>>>    "CHAOS" <chaos-l at rtpnet.org <mailto: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  
>>> <mailto: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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>>
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