| 1900 B.C. | 1400 B.C. | 800 B.C. | ||||
|---|---|---|---|---|---|---|
| Summer Solstice | Betelgeuse rising | N. 87° E. | Betelgeuse rising | N. 90° E. | γ Geminorum rising | N. 68° E. |
| Arcturus setting with hill 3′ high | N. 18° W. | Arcturus setting (late) | N. 16° W. | (“Alhena” mag. 1·9.) | ||
| α Serpentis setting | N. 53° W. | |||||
| Winter Solstice | Sheat rising (early) | N. 72° E. | Castor setting | N. 37° W. | α Capricorni rising | S. 66° E. |
| Markab rising (late) | S. 89° E. | Pollux setting | N. 42° W. | |||
It is obvious that a star used all the year round for night work will warn the sunrise at some one of the yearly festivals.
When the stars having the same declinations are considered from this point of view, the star actually used, and therefore the date of its use, may generally be gathered. I shall show subsequently that some of the stars in the above lists were actually observed in British as well as in Grecian temples.
[19] Dr. O. Danckworth, Vierteljahrschrift der Astronomischen Gesellschaft, 16. Jahrgang 1881, p. 9. Dr. Stockwell’s results have been communicated to me by letter. Some, but not all, of Dr. Lockyer’s calculations appeared in The Dawn of Astronomy.
CHAPTER XII
ASTRONOMICAL HINTS FOR ARCHÆOLOGISTS—Continued.
I next come to the sun observations.
First we must consider the astronomical differences between the rising of a star and of the sun, by which we generally mean that small part of the sun’s limb first visible.
It is frequently imagined that for determining the exact place of sunrise or sunset in connection with these ancient monuments we have to deal with the sun’s centre, as we should do with the sun half risen. As a matter of fact, we must consider that part of the sun’s limb which first makes its appearance above the horizon; the first glimpse of the upper limb of the sun is in question, say, when the visible limb is 2′ high; and we must carefully take the height of the hills over which it rises into account.