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Re: Refraction:Which formula for Heights below 15°
From: Bela Kovacs
Date: 2022 May 18, 00:01 +0200
From: Bela Kovacs
Date: 2022 May 18, 00:01 +0200
Herman:
I've attached a photo from this book (p. 280):
Sean E. Urban - P. Kenneth Seidelmann
"Explanatory Supplement to the Astronomical Almanac, 3rd Edition"
And I found an interesing PhD dissertation:
Wilson, Teresa, "Evaluating the Effectiveness of Current Atmospheric Refraction Models in Predicting
Sunrise and Sunset Times", Open Access Dissertation, Michigan Technological University, 2018.
https://digitalcommons.mtu.edu/etdr/697/
Regards,
Bela
I've attached a photo from this book (p. 280):
Sean E. Urban - P. Kenneth Seidelmann
"Explanatory Supplement to the Astronomical Almanac, 3rd Edition"
And I found an interesing PhD dissertation:
Wilson, Teresa, "Evaluating the Effectiveness of Current Atmospheric Refraction Models in Predicting
Sunrise and Sunset Times", Open Access Dissertation, Michigan Technological University, 2018.
https://digitalcommons.mtu.edu/etdr/697/
Regards,
Bela
Herman Dekker <NoReply_Dekker@fer3.com> ezt írta (időpont: 2022. máj. 16., H, 22:47):
Hello Navigators,
One question about calculation refraction.
If the measured altitude (h) is <15° I learned in Franks Advance Moderen Cel.Nav. Workshop:I: R=1.0’/Tan [h+6.82/(h+4.024)]
In Henning Umland’s “A Short Guide to Cel.Nav.” the used formula is:
II: R=1.0’/Tan[h+7.31/(h+4.4)]
Can you explain the difference values?
If I calculated f.i. for h=0°,1°, 5° and 10° the calculated values are:
h= 0° 1° 5° 10°
I: 33.79’ 24.29’ 9.92’ 5.40’
II: 34.47’ 24.32’ 9.88’ 5.39’
The difference is negligible. but where come the different values in the formula from?
Regards.
HermanD
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