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Re: (meteorobs) Re: LM's and the Milky Way



Op Sun, 30 Aug 1998 GeoZay@aol.com schreef:

> In a message dated 98-08-30 09:46:09 EDT, you write:
> 
> marco<< 
>  The apparent upper limit to the Lm a person can estimate as pointed out 
>  by George for his case (6.0 in his case) is interresting, since I have 
>  noted a similar phenomenon myself, albeit (and there we go again: this is 
>  in line with what Bob explains and I already alluded to!) in my case the 
>  upper limit seems to be 7.0-7.1. I reach up to 6.8-6.9 and occasionally 
>  (very rare) 7.0 from Biddinghuizen. In Southern France and Spain I 
>  reached 7.0. But even under the best of conditions, I have never come 
>  higher, similar to George's 'upper limit' which in his case is at 6.0. For 
>  example, I observed 
>  from 2100m Calar Alto observatory in the Spanish Sierra during the alfa 
>  Monocerotids of 1995. The sky there was much darker than in Alcudia 
>  (lower Guadix-Baza basin in southern Spain) the previous nights, with 
>  gegenschein and even the faint 'light bridge' really blazing from the sky. 
>  But my Lm was almost similar (6.8-7.0 from Alcudia: 7.0-7.1 from Calar Alto)!
>  Perhaps, due to some reason, there is a upper limit to your perception. 
>  Most likely, where that limit lies is personal. I.e., even from the 
>  mentioned Calar Alto I never obtained the 7.3 Lm's of for example Norman, 
>  nothwithstanding extremely good sky conditions.
>   >>
> 
> I wonder if the response in our eyes is something similiar to film? On film,
> the grain emulsion size and number is varied with it's film speed. For
> example, the grains on very fast films are large and not as many per area. For
> slow film the grains are very small and numerous. I wonder if the number of
> cone and rod cells vary appreciably in individuals as well? Maybe for someone
> like me with low perception has a lesser/or greater number of light sensitive
> cells and someone like bob and marco have the opposite of whatever would allow
> their eyes to be more sensitive? Just a thought.
> GeoZay
> 

Hi George,

That wouldn't surprise me. A few days ago I already mailed that I 
recently read about research indicating that colorblind people have 
better night vision. That presumably is due too such things, since the 
ability to see colours is dependend on the number of either cones or rods 
(am not quite sure which of the two).
I am color contrast blind, which means that I do see colors, but not the 
many gradations of 'normal' people (by the way, that seems to be a very 
common thing, only many people simply don't know it from themselves. And 
males are 4 times more prone than females for this 'defect'). Sometimes, I 
simply see no difference 
between two differently colored items where others do see a difference. 
So from a meteor point of view, I might be lucky....
Has Bob ever done the colored dot test?

-Marco


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