DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.15#0158
146 THE GREAT PYRAMID.
shadows would be so far shortened, that a smaller
number of observers only could follow the shadows'
motions ; but in some respects, the observations in
this part of the year could be more readily and
exactly made than in winter, when the shadow-
spaces of various width would range along the
entire length of the gallery.
Similar remarks would apply to the moon,
which could also be directly observed. The
planets and stars of course could only be observed
directly.
The Grand Gallery could be used for the obser-
vation of any celestial body southing higher than
26°i8' above the horizon; but not very effectively
for objects passing near the zenith. The Pleiades
could be well observed. They southed about
63f° above the horizon in the year 2140 B.c., or
thereabouts, when they were on the equinoctial
colure.1 But if I am right in taking the year
1 This date is sometimes given earlier, but when account is taken
of the proper motion of these stars we get about the date above
mentioned. I cannot understand how Dr. Ball, Astronomer Royal
for Ireland, has obtained the date 2248 B.c., unless he has taken
the proper motion of Alcyone the wrong way. The proper motion
of this star during the last 4,000 years has been Such as to increase
the star's distance from the equinoctial colure ; and therefore, of
course, the actual interval of time since the star was on the colure is
less than it would be calculated to be if the proper motion were
neglected.
shadows would be so far shortened, that a smaller
number of observers only could follow the shadows'
motions ; but in some respects, the observations in
this part of the year could be more readily and
exactly made than in winter, when the shadow-
spaces of various width would range along the
entire length of the gallery.
Similar remarks would apply to the moon,
which could also be directly observed. The
planets and stars of course could only be observed
directly.
The Grand Gallery could be used for the obser-
vation of any celestial body southing higher than
26°i8' above the horizon; but not very effectively
for objects passing near the zenith. The Pleiades
could be well observed. They southed about
63f° above the horizon in the year 2140 B.c., or
thereabouts, when they were on the equinoctial
colure.1 But if I am right in taking the year
1 This date is sometimes given earlier, but when account is taken
of the proper motion of these stars we get about the date above
mentioned. I cannot understand how Dr. Ball, Astronomer Royal
for Ireland, has obtained the date 2248 B.c., unless he has taken
the proper motion of Alcyone the wrong way. The proper motion
of this star during the last 4,000 years has been Such as to increase
the star's distance from the equinoctial colure ; and therefore, of
course, the actual interval of time since the star was on the colure is
less than it would be calculated to be if the proper motion were
neglected.