Almanac spreadsheets in 2021

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Comparisons with the 2021 Nautical Almanac Commercial Edition show that our spreadsheets remain sufficiently accurate for the year 2021 without the need for any changes or updates in the calculations.

Spreadsheets aries_stars.xls and what_star.xls were modified with the changed spelling of one star’s name (Alnair). Archive TAR and ZIP files were also updated accordingly.

Astron 2.00 release

In 2015 “an anonymous benevolent user” of the original Navigation Spreadsheets combined several of them into a single unit named Astron to provide a much more user friendly interface and functionality.

In 2018 version 2.00 has been rewritten as a web page and can be run online on recent versions of popular browsers and, for seafarers, can also be run offline with Chrome, Firefox, and Opera.

https://friendsofthevigilance.org.uk/Astron/Astron.html

Coding in Javascript has enabled some improvements and additions. There is now a sky map addition to the Planner section, a sight log, a sight plotter, and an extended lunar section. Future developments are only intended for version 2.

Extensive user notes can be accessed from

https://friendsofthevigilance.org.uk/Astron/

(Note: both links were updated on July 22, 2020.)

Astron200

New releases and updates

In 2015 “an anonymous benevolent user” of the original Navigation Spreadsheets combined several of them into a single unit to provide a much more user friendly interface and functionality. The result (named “Astron“) is hereby released with its creator’s consent.

Astron_V1.0To download, visit:

GitHub

Original website

During this development process a small error (less than 1’) in the GHA calculation was discovered and corrected in all almanac spreadsheets. We therefore recommend downloading the latest version of the suite; in particular, the spreadsheets: aries_stars, sun, mercury, venus, moon, mars, jupiter, saturn, uranus, neptune, what_star, polaris, polaris_lha.

Almanac spreadsheets in 2014

Selected comparisons with Nautical Almanac 2014 Commercial Edition indicate that almanac spreadsheets are good for the year 2014 as they are – with one small update described below.

The newest versions of aries_stars.xls and what_star.xls have the computed SHA of Rigil Kent. increased by additional 0.3′ before display (the original adjustment had been +0.6′, so now it is +0.9′, see cells W305 and W306) in order to better match with published almanac values.

A possible explanation for this oddity has been suggested by Antoine M. “Kermit” Couëtte in his recent NavList post.

Downloads of all (including updated) spreadsheets are available on our main page.

(August 31, 2013: Additional details were provided on the same NavList thread by Paul Hirose and Dave Walden.)

 

(first published on August 25, 2014)