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Marcel, you wrote:
"Could it be, that in the  1976 edition they removed the lower part of the
atmosphere since there are  sufficient balloon data available in this most
variing part between 0 and 30  to 40km, and left the data for the upper parts
which seem to be more  difficult to obtain (rockets, LIDAR)?"

The balloon data has been around  for a long time. The absence of interest in
the lower atmosphere I think has  more to do with the intended use of the US
Standard Atmosphere.

And:
"Based on the available graphs, I analysed in the meantime the  seasonal and
latitudinal influence on the refraction at the horizon, the dip  at the
horizon and the corresponding K-factor  (used for terrestrial  refraction and
in simplified formulae for calculating the dip) for a height  of 10m (which I
thought to be a reasonable value for nautical  navigation).These calculations
were done iterative to come "very close" to  the actual edge of the horizon.
The results show that latitude and season  (independent of the seasonal
temperature differences) are each of them  responsible for a variation of
about 2arc min. I can provide more details on  these results, if this is of
interest."

Interest?? Yes, yes, yes. Can  you tell us what you found out and how you
went about it,  please.

-FER
42.0N 87.7W, or 41.4N  72.1W.
www.HistoricalAtlas.com/lunars

   

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