Clive Ruggles


… is the study of beliefs and practices relating to the sky in the past, especially in prehistory, and the uses to which people's know- ledge of the skies was put.


Professional bodies

Free software tools

Basic declination calculator


by Andrew Smith

See the Tools page for more info


Springer Handbook (2014):


Ocarina Books publishes and distributes books relating to archaeo- and ethnoastronomy



This list of my books and selected papers and articles contains links and downloadable copies where available.

Basic declination calculator

This calculator uses the same formulae as “GETDEC”, the program referred to in Astronomy in Prehistoric Britain and Ireland (p. 169) and in various publications by myself and others.

The original program is no longer accessible.

deg   min   sec  

deg   min   sec  

deg   min   sec  



Except in discussing putative high-precision lunar phenomena, the apparent declination is sufficient for all archaeoastronomical purposes. While the program quotes results to arc-second precision, a precision of 0.1 degrees (6 arc minutes) is quite sufficient in most contexts.

The program applies a mean refraction correction to the observed altitude and (for geocentric lunar declinations) mean lunar parallax.

See the Astronomy boxes in Astronomy in Prehistoric Britain and Ireland for more information.

Astronomical heritage

Portal to the Heritage of Astronomy

Read more on the UNESCO–IAU Portal to the Heritage of Astronomy and about astronomical heritage in general

Free downloads

ICOMOS–IAU Thematic Studies on Astronomical Heritage

No. 1 (2010): See here for more information or click here to download a copy directly (46 Mb)

No. 2 (2017): See here for more information or click here to download a copy (19 Mb)


Astronomical World Heritage


Download a copy of an article published in A&G (Aug 2019 issue)

Stonehenge and Ancient Astronomy


Download a copy of the Royal Astronomical Society’s factsheet

Alice Ruggles Trust

If you are looking for things related to Alice and/or information about stalking, please visit the Alice Ruggles Trust website