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George wrote
> I'm pleased that Marcel has followed up my lead to Andrew Young's useful
> series, and that Andy has come up with the goods, as I expected he would.

Yes, I followed your suggestion, and indeed Andy Young was very helpful in
discussing the subject via mail.

George asks further
> Presumably, Sunset science 4 has references to the previous 3 instalments.
> Is it the concluding item in that series, or are there others to follow?
> It
> would be helpful if Marcel would list references to all the items in this
> series for which he has details. No doubt, several listmembers would find
> them interesting.

The three preceiding papers are indeed mentioned. To make it easier for all
those who are interested, I just add the references from NASA ADS by
copy/paste at the end of this mail. The abstract can be read at ADS.
Unfortunately all these articles can not be downloaded for free. I was not
able to find out whether the series will continue or not.

Let me just mention the last part of his conclusions:

"Refraction within about 5deg of the horizon is so variable that no a priori
formula or table can be expected to give accurate values there; the local
lapse rate and thickness of the boundary layer above the observer must be
known. However, numerical integration using standard lapse rate, matched to
the actual temperature and pressure at the observer, should give values good
to a minute of arc or so - that is, good enough for telescope pointing -
down to 2deg or 3deg apparent altitude.
Below that, numerical integrations will give useful values if the actual
boundary-layer lapse rate and thickness are known, but only the bottom
kilometer or so of the atmosphere needs to be measured, and ordinary balloon
soundings are adequate. At and below the astronomical horizon, the
refraction depends primarily on atmospheric structure below the observer and
varies so much (tens of minutes, or even several degees) that only very
crude predictions can be made. The observed time of sunset at a sea horizon
often varies by a few minutes from day to day, and the variations increase
with height above the sea."

That is more or less what also Frank found after having calculated various
models using the BAS pocedure, as Andy Young calls it. I hope that Frank's
transfer function for calculating refraction as a function of altitude and
height receives the appreciation it deserves.

Marcel

Here now the references:

      Title:
     Sunset science. I. The mock mirage
      Authors:
     Young, Andrew T.; Kattawar, George W.; Parviainen, Pekka
      Journal:
     Applied Optics LP, vol. 36, Issue 12, pp.2689-2700
      Publication Date:
     04/1997
      Origin:
     AIP; OSA
      Bibliographic Code:
     1997ApOpt..36.2689Y


      Title:
     Sunset Science. II. A useful diagram
      Authors:
     Young, Andrew T.; Kattawar, George W.
      Journal:
     Applied Optics LP, vol. 37, Issue 18, pp.3785-3792
      Publication Date:
     06/1998
      Origin:
     AIP; OSA
      Bibliographic Code:
     1998ApOpt..37.3785Y



      Title:
     Sunset science. III. Visual adaptation and green flashes
      Authors:
     Young, Andrew T.
      Journal:
     Journal of the Optical Society of America A: Optics, Image Science, and
Vision, Volume 17, Issue 12, December 2000, pp.2129-2139
      Publication Date:
     12/2000
      Origin:
     AIP; OSA
      Bibliographic Code:
     2000OSAJ...17.2129Y


      Title:
     Sunset Science. IV. Low-Altitude Refraction
      Authors:
     Young, Andrew T.
      Affiliation:
     AA(Department of Astronomy, San Diego State University, 5500 Campanile
Drive, San Diego, CA 92182-1221 aty@mintaka.sdsu.edu)
      Journal:
     The Astronomical Journal, Volume 127, Issue 6, pp. 3622-3637. (AJ
Homepage)
      Publication Date:
     06/2004
      Origin:
     UCP
      AJ Keywords:
     Atmospheric Effects
      Abstract Copyright:
     (c) 2004: The American Astronomical Society
      DOI:
     10.1086/420806
      Bibliographic Code:
     2004AJ....127.3622Y

   

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