difference arises, of course, from the uncertainty of the time of departure and the length of the
journey of the Magi.
As this astronomical argument is often very carelessly and erroneously stated, and as the
works of Kepler and Ideler are not easy of access, at least in America (I found them in the Astor
Library), I may be permitted to state the case more at length. John Kepler wrote three treatises on
the year of Christ’s birth, two in Latin (1606 and 1614), one in German (1613), in which he discusses
with remarkable learning the various passages and facts bearing on that subject. They are reprinted
in Dr. Ch. Frisch’s edition of his Opera Omnia (Frcf. et Erlang. 1858–’70, 8 vols.), vol. IV. pp.
175 sqq.; 201 sqq.; 279 sqq. His astronomical observations on the constellation which led him to
this investigation are fully described in his treatises De Stella Nova in Pede Serpentarii (Opera,
vol. II. 575 sqq.), and Phenomenon singulare seu Mercurius in Sole (ibid. II. 801 sqq.). Prof. Ideler,
who was himself an astronomer and chronologist, in his Handbuch der mathemat. und technischen
Chronologie (Berlin, 1826, vol. III. 400 sqq.), gives the following clear summary of Kepler’s and
of his own observations:
"It is usually supposed that the star of the Magi was, if not a fiction of the imagination,
some meteor which arose accidentally, or ad hoc. We will belong neither to the unbelievers nor
the hyper-believers (weder zu den Ungläubigen noch zu den Uebergläubigen), and regard this starry
phenomenon with Kepler to be real and well ascertainable by calculation, namely, as a conjunction
of the Planets Jupiter and Saturn. That Matthew speaks only of a star (ἀστήρ), not a constellation
(ἄστρον), need not trouble us, for the two words are not unfrequently confounded. The just named
great astronomer, who was well acquainted with the astrology of his and former times, and who
used it occasionally as a means for commending astronomy to the attention and respect of the laity,
first conceived this idea when he observed the conjunction of the two planets mentioned at the
close of the year 1603. It took place Dec. 17. In the spring following Mars joined their company,
and in autumn 1604 still another star, one of those fixed star-like bodies (einer jener fixstern-artigen
Körper) which grow to a considerable degree of brightness, and then gradually disappear without
leaving a trace behind. This star stood near the two planets at the eastern foot of Serpentarius
(Schlangenträger), and appeared when last seen as a star of the first magnitude with uncommon
splendor. From month to month it waned in brightness, and at the end of 1605 was withdrawn from
the eyes which at that time could not yet be aided by good optical instruments. Kepler wrote a
special work on this Stella nova in pede Serpentarii (Prague, 1606), and there he first set forth the
view that the star of the Magi consisted in a conjunction of Saturn, Jupiter and some other
extraordinary star, the nature of which he does not explain more fully." Ideler then goes on to report
(p. 404) that Kepler, with the imperfect tables at his disposal, discovered the same conjunction of
Jupiter and Saturn a.u. 747 in June, August and December, in the sign of the Pisces; in the next
year, February and March, Mars was added, and probably another extraordinary star, which must
have excited the astrologers of Chaldaea to the highest degree. They probably saw the new star
first, and then the constellation.
Dr. Münter, bishop of Seeland, in 1821 directed new attention to this remarkable discovery,
and also to the rabbinical commentary of Abarbanel on Daniel, according to which the Jewish
astrologers expected a conjunction of the planets Jupiter and Saturn in the sign of the Pisces before
the advent of the Messiah, and asked the astronomers to reinvestigate this point. Since then Schubert
of Petersburg (1823), Ideler and Encke of Berlin (1826 and 1830), and more recently Pritchard of
London, have verified Kepler’s calculations.A.D. 1-100.