Next message: Frank Reed: "Re: Attachments on Nav-L list"
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
