1Orb. And becauſe the diſtance of the Sun from the Earth,
tains by common conſent 1208. Semidiameters of the ſaid Earth,
and the diſtance of the fixed Stars (as hath been ſaid) 2160.
Semediameters of the grand Orb, therefore the Semediameter of
the Earth is much greater (that is almoſt double) in compariſon
of the grand Orb, than the Semediameter of the grand Orb, in
relation to the diſtance of the Starry Sphære; and therefore the
variation of aſpect in the fixed Stars, cauſed by the Diameter of
the grand Orb, can be but little more obſervable, than that which
is obſerved in the Sun, occaſioned by the Semediameter of the
Earth.
tains by common conſent 1208. Semidiameters of the ſaid Earth,
and the diſtance of the fixed Stars (as hath been ſaid) 2160.
Semediameters of the grand Orb, therefore the Semediameter of
the Earth is much greater (that is almoſt double) in compariſon
of the grand Orb, than the Semediameter of the grand Orb, in
relation to the diſtance of the Starry Sphære; and therefore the
variation of aſpect in the fixed Stars, cauſed by the Diameter of
the grand Orb, can be but little more obſervable, than that which
is obſerved in the Sun, occaſioned by the Semediameter of the
Earth.
The diſtance of
a fixed ſtar of the
ſixth magnitude,
how much it is, the
ſtar being ſuppoſed
to be equal to the
Sun.
a fixed ſtar of the
ſixth magnitude,
how much it is, the
ſtar being ſuppoſed
to be equal to the
Sun.
In the fixed ſtars
the diverſitie of
ſpect, cauſed by
the grand Orb, is
little more then
that cauſed by the
Earth in the Snn.
the diverſitie of
ſpect, cauſed by
the grand Orb, is
little more then
that cauſed by the
Earth in the Snn.
SALV. It is doubtleſſe an errour; for a fixed Star of the ſixth
magnitude, which by the computation of this Authour, ought,
for the upholding the propoſition of Copernicus, to be as big as
the whole grand Orb, onely by ſuppoſing it equal to the Sun,
which Sun is leſſe by far, than the hundred and ſix milionth part
of the ſaid grand Orb, maketh the ſtarry Sphære ſo great and high
as ſufficeth to overthrow the inſtance brought againſt the ſaid
pernicus.
magnitude, which by the computation of this Authour, ought,
for the upholding the propoſition of Copernicus, to be as big as
the whole grand Orb, onely by ſuppoſing it equal to the Sun,
which Sun is leſſe by far, than the hundred and ſix milionth part
of the ſaid grand Orb, maketh the ſtarry Sphære ſo great and high
as ſufficeth to overthrow the inſtance brought againſt the ſaid
pernicus.
A ſtar of the
ſixth magnitude,
ſuppoſed by Tycho
and the Authour
of the Book of
cluſions, an
dred and ſix
ons of times bigger
than needs.
ſixth magnitude,
ſuppoſed by Tycho
and the Authour
of the Book of
cluſions, an
dred and ſix
ons of times bigger
than needs.
SAGR. Favour me with this computation.
SALV. The ſupputation is eaſie and ſhort. The Diameter of
the Sun, is eleven ſemediameters of the Earth, and the Diameter
of the grand Orb, contains 2416. of thoſe ſame ſemediameters,
by the aſcent of both parties; ſo that the Diameter of the ſaid
Orb, contains the Suns Diameter 220. times very near. And
becauſe the Spheres are to one another, as the Cubes of their
ameters, let us make the Cube of 220. which is 106480000. and
we ſhall have the grand Orb, an hundred and ſix millions, four
hundred and eighty thouſand times bigger than the Sun, to which
grand Orb, a ſtar of the fixth magnitude, ought to be equal,
cording to the aſſertion of this Authour.
the Sun, is eleven ſemediameters of the Earth, and the Diameter
of the grand Orb, contains 2416. of thoſe ſame ſemediameters,
by the aſcent of both parties; ſo that the Diameter of the ſaid
Orb, contains the Suns Diameter 220. times very near. And
becauſe the Spheres are to one another, as the Cubes of their
ameters, let us make the Cube of 220. which is 106480000. and
we ſhall have the grand Orb, an hundred and ſix millions, four
hundred and eighty thouſand times bigger than the Sun, to which
grand Orb, a ſtar of the fixth magnitude, ought to be equal,
cording to the aſſertion of this Authour.
SAGR. The errour then of theſe men, conſiſteth in being
treamly miſtaken, in taking the apparent Diameter of the fixed
Stars.
treamly miſtaken, in taking the apparent Diameter of the fixed
Stars.
SALV. This is one, but not the onely errour of them; and
indeed, I do very much admire how ſo many Aſtronomers, and
thoſe very famous, as are Alfagranus, Albategnus, Tebizius, and
much more modernly the Tycho's and Clavius's, and in ſumm,
all the predeceſſors of our Academian, ſhould have been ſo groſly
miſtaken, in determining the magnitudes of all the Stars, as well
ſixed as moveable, the two Luminaries excepted out of that
ber; and that they have not taken any heed to the adventitious
irradiations that deceitfully repreſent them an hundred and more
times bigger, than when they are beheld, without thoſe
indeed, I do very much admire how ſo many Aſtronomers, and
thoſe very famous, as are Alfagranus, Albategnus, Tebizius, and
much more modernly the Tycho's and Clavius's, and in ſumm,
all the predeceſſors of our Academian, ſhould have been ſo groſly
miſtaken, in determining the magnitudes of all the Stars, as well
ſixed as moveable, the two Luminaries excepted out of that
ber; and that they have not taken any heed to the adventitious
irradiations that deceitfully repreſent them an hundred and more
times bigger, than when they are beheld, without thoſe