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Re: Definition of the twilight intervals
From: Sean C
Date: 2015 Aug 25, 08:48 -0700
From: Sean C
Date: 2015 Aug 25, 08:48 -0700
However, modern editions of Bowditch's "The American Practical Navigator" do not seem
to be consistent with the definition of astronomical twilight.
In the 2002 online bicentennial edition (the latest to which I have easy access),
astronomical twilight is defined as the interval between -0 degr 50 arcmin
and -18 degr (table 1516 on p. 227) while the Glossary of Marine Navigation
in the same publication defines it as the interval between -12 degr and -18
degr (p. 725).
Whom should one contact to point out this inconsistency?
Rob van Gent
Rob,
Apologies for replying to this so long after you posted it, but I was just browsing through my copy of Bowditch, saw the table you were referring to and was reminded of your question. Bowditch is prepared and published by the National Geospatial-Intlligence Agency (Formerly the National Imagery and Mapping Agency). Their website gives their mailing address as:
National Geospatial-Intelligence Agency
Office of Corporate Communications
Public Affairs Branch, MS N73-OCCAE
7500 GEOINT Drive
Springfield, Virginia 22150-7500
...and their email address is: publicaffairs -at- nga.mil. Hope that helps.
Regards,
Sean C.
