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Martin Dubs
登録日: 2014.03.04 記事: 56
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日時: Sun Mar 09, 2014 8:44 am 記事の件名: Atmospheric corrections |
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Hello SonotaCo,
I have a question about atmospheric corrections in UA2.
1. What are the units or formula of the correction factor atc for refraction in the profile?
2. Is it also possible to correct for atmospheric extinction, e.g. with a correction factor proportional to (air mass - 1)?
Just to make sure, the celestial coordinates in the positions and radiants in UA2 and elements in UO2, are they all referenced to J2000 and transformed to equinox of the date when calculating azimut and elevation?
Thanks for clarifying.
Martin
PS: with the newest version UO2.31 I am perfectly happy, no more problems with the time zone |
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SonotaCo Site Admin
登録日: 2004.08.07 記事: 12671 所在地: 139.67E 35.65N
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日時: Sun Mar 09, 2014 10:01 am 記事の件名: Re: Atmospheric corrections |
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Hi
Martin Dubs wrote: | 1. What are the units or formula of the correction factor atc for refraction in the profile? |
It is arc second.
As for atmospheric correction R, UA2 uses below
z < 79 degree: R=a*tan(z) where a = atc parameter .unit is arc second. z = zenith distance.
z >=79 degree: R is computed from atc and table value (listed in TENMON NENKAN pushed in Japan).
Martin Dubs wrote: | 2. Is it also possible to correct for atmospheric extinction, e.g. with a correction factor proportional to (air mass - 1)? |
No.
Martin Dubs wrote: | the celestial coordinates in the positions and radiants in UA2 and elements in UO2, are they all referenced to J2000 |
yes.
The celestial coordinates are decided by reference star catalogue values that is used in UFO series.
Currently UA2 uses SKY2000 Master Catalog Version 4 (Goddard Space Flight Center 2002). It uses J2000.
Martin Dubs wrote: | and transformed to equinox of the date when calculating azimut and elevation? |
Almost Yes. There are so many trivial factors in az ev computing so this is difficult to answer generally and clearly.
Well.... are you doing some project? |
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Martin Dubs
登録日: 2014.03.04 記事: 56
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日時: Sun Mar 09, 2014 8:58 pm 記事の件名: |
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Hi,
thanks for the prompt reply, just about what I assumed. The Swiss meteor astronomy group (http://www.meteorastronomie.ch/)
is thinking about a video observation network and we try to figure out the necessary hard- and software. We probably have some more questions soon.
Regards, Martin |
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