The only large celestial globe evidently surviving from antiquity is that in the Naples Archaeological Museum, held upon the shoulders of the statue of Atlas, known as the Farnese Atlas. The globe is marble, 65 cm in diameter, covered with constellations depicted in relief (no stars). The question of whose astronomy inspired the artist's celestial vision has long been investigated and debated.
A scrupulous scholarly history, covering centuries of researches into the Farnese globe, was provided in 1987 by Vladimiro Valerio in Globusfreund. Valerio notes that J.Lalande and N.Halma were among the earliest figures knowledgeable in astronomy to take an interest in the Farnese globe about 200y ago, and that Matteo Fiorini provided an able mathematician's perspective on it over a century ago.
In 1898, the eminent scholar Georg Thiele argued in detail (though undogmatically) that the sculptor followed the astronomy of Hipparchos (fl. 130 BC). (See translation of Thiele by H.Thurston.)
Valerio (op cit p.105) provided careful measurements of the key features of the Farnese globe, and suggested the possibility of a Ptolemaic origin.
On 2005/1/11, with promotion by the American Astronomical Society (AAS) and
the Journal for the History of Astronomy, Bradley Schaefer (JHA
Ed.Board) — ignoring the globe's numerous
contra-Hipparchan features — appropriated
Thiel's Hipparchan thesis and created a “new” discovery out of it
for a world press-story, using
simple on-colure stellar evidence remarkably similar to Thiel's.
[Twice dishonored? Several Nazi destroyers were sunk by Brits in a fjord near
Narvik in the Spring of 1940. The rusting hull of one of them is still visible
there: the “Georg Thiele”.]
But Schaefer unfortunately attempted to go beyond Thiele's properly cautious
discussion — announcing via AAS the sort of unattainable (pop-sci
newsbite-)certainty that the “science press” prefers:
[1] Schaefer adds dubious photogrammetry on
many more-scattered, valuelessly-mushy “star”-positions.
[2] He effectively averages two statistically-inconsistent
precessionally-computed dates 300 yrs apart (each over
a century before and after Hipparchos) to arrive at his Hipparchan-epoch
conclusion.
[3] Schaefer mis-uses atmospheric extinction,
to tamper with his own potentially valuable finding that the Farnese globe's
polar circles were arranged for 38°-39°N latitude, thereby (quite fallaciously) nudging the globe's latitude to
come out consistent with Hipparchos' (36°N).
Dennis Rawlins has posted criticisms of Schaefer's shaky conclusion and shakier procedures.
[It is demonstrated that Schaefer is astonishingly ignorant of key data (DATA WHICH ARE QUITE WELL-KNOWN
TO EVERY SPECIALIST IN THE FIELD) that firmly delimit the bounds of Hipparchos'
constellations — bounds which are frequently in gross conflict with
those displayed upon the Farnese globe.] Provided further are evidences of JHA
slapdash-refereeing (which led to
brushing aside JHA Assoc Editor James Evans' prescient 2004
pre-publication doubts about the paper) — along with DR's own (explicitly
tentative-speculative) proposal for a possible source of the Farnese globe's
astronomy: Krates of Mallos.
[A] The points on the globe corresponding to the most potentially useful
epoch-sensitive stars (the on-colure ones) suggest the early 2nd century,
Krates' era.
[B] Krates was famous as a globist.
[C] He emphasized the galactic circle, a fragment of which may survive on
the Farnese globe (at Cygnus), a hitherto-mysterious line-segment which DR revealed (2005/4/1) exhibits both the direction and the
location of the Milky Way.
[D] Krates' Pergamon 39°N latitude was consistent with the globe's.
A great deal of further expert investigation of the Farnese controversy (as well as helpful accessory material, including the 1739 M.Folkes projection of the Farnese globe) has been contributed by physicist Dennis Duke and is available at “www.csit.fsu.edu/~dduke/farnese”. [The Duke paper is due to be published in the 2006 Feb issue of the Journal for the History of Astronomy.]
[On 2005/7/27&29, Dennis Rawlins visited the Naples Archaeological Museum to view the Farnese globe 1st-hand. The Rawlins photographs resulting
from these visits have been transmitted to Duke (since Schaefer
had earlier refused to acknowledge
Duke's request to use Schaefer's photos), for assistance in checking the
accuracy of the Folkes projection, which Duke is using for his polite but
devastating 2006 Feb JHA paper on the
Farnese-globe's numerous non-Hipparchan aspects — a paper whose merciful restraint has (on the
evidence of a lordly, insulting, accusatory 2005/9/18 BS email) gone
astonishingly unappreciated by Schaefer.
[We are here glad to compliment the DR-hating JHA for ultimately doing
the right thing in publishing Duke's quietus to Farnese-BS. Let's hope that
this creditable event can act as a spark in initiating a long-needed apolitical
truth-priority trend in the astronomical-history field.]
Note: neither DR nor Schaefer were able to photograph the globe from above.
This limitation was one contributing factor in the Schaefer photogrammetric
approach's accuracy-problems. Duke has been able to overcome this difficulty by
using one of Thiele's 1898 photos.]
[Revised 2005/9/16-2006/1/14.]
