Stonehenge and Other British Stone Monuments Astronomically Considered

by Sir Norman Lockyer

I.
Monument.	Position.												Alignment.	Az.						Hills.				Decl. N.				Date B.C.
	Lat. N.						Long. W.
Tregaseal	50	°	8	′	0	″	5	°	39	′	20	″	Circ. to Carn Kenidjack	N.	12	°	8	′	E.	4	°	0	′	42	°	33	′	2330
The Hurlers	50		31		0		4		27		20		S. circ. over cent. circ.	N.	11		15		E.	3		24		41		38		2170
													Cent. circ. over N. circ.	N.	14		18		E.	3		24		41		9		2090
													N. circ. over N.E. barrow	N.	18		44		E.	3		24		40		6		1900
Merrivale	50		33		15		4		2		30		Circ. to remains of cromlech	N.	15		0		E.	3		1		40		36		1990
													Direction of smaller avenue	N.	24		25		E.	5		0		39		55		1860
Fernworthy	50		38		30		3		54		10		Direction of Avenue	N.	13		0		E.	1		15		39		7		1720
														N.	14		20		E.	1		15		38		51		1670
Stanton Drew	51		22		0		2		34		20		Cent. of Gt. Circ. to Quoit	N.	17		59		E.	2		33		38		38		1620
Fernworthy	50		38		30		3		54		10		Direction of Avenue	N.	15		45		E.	1		15		38		34		1610
Merry Maidens	50		3		40		5		35		25		Circ. to stone in the road	N.	11		45		E.	0		12		38		27		1590
Stanton Drew	51		22		0		2		34		20		S.W. circ. to centre of Gt. Circ.	N.	19		51		E.	1		44		37		30		1420
II.
Monument.	Position.												Alignment.	Az.						Hills.				Decl. N.				Date B.C.
	Lat. N.						Long. W.
Trowlesworthy	50	°	27	′	30	″	4	°	0	′	20	″	Direction of primary avenue	N.	7	°	0	′	E.	2	°	52	′	41	°	24	′	2130
													Direction of final avenue	N.	12		0		E.	2		52		41		6		2080
Longstone (Tregaseal)	50		8		10		5		38		20		Longstone to Chûn Cromlech	N.	9		0		E.	1		43		40		39		2000
Lee Moor	50		26		30		3		59		40		Direction of avenue	N.	22		0		E.	2		28		38		17		1500

In some cases, for one reason or another, this arrangement was not carried out, and Capella, in spite of the objection I have stated, was used in the following circles:—

CAPELLA AS A CLOCK-STAR.

Monument.	Position.												Alignment.	Az.						Hills.				Decl. N.				Date B.C.
	Lat. N.						Long. W.
I.
Boscawen-un	50	°	5	′	20	″	5	°	37	′	0	″	Circ. to Stone Cross	N.	43	°	15	′	E.	2	°	7	′	29	°	36	′	2250
Merry Maidens	50		3		40		5		35		25		Circ. over the “Pipers”	N.	38		26		E.	0		20		29		58		2100
II.
The Nine Maidens	50		28		20		4		54		30		Direction of Nine Maidens row	N.	28		0		E.	0		0		33		47		1480
Stripple Stones	50		32		51		4		37		35		Centre to N.E. bastion	N.	26		0		E.	0		22		34		38		1320

At the Merry Maidens, however, with nearly a sea horizon, when Arcturus ceased to be circumpolar and rose in Azimuth N. 11° 45′ E., it replaced Capella, and was used as a clock-star after 1600 B.C.

In this system of night observation we have the germ of the use in later times of an instrument called the “night-dial,” specimens of which, dating from the fourteenth century, can be seen in our museums. The introduction of graduated circles permitted the employment of circumpolar stars, and the “guards” of the Little Bear or the “pointers” of the Great Bear were thus used. There was a disc with a central aperture through which the pole star could be observed; the disc could be adjusted for every night in the year; an arm was then moved round so that the direction of the pointers (or the guards) with regard to the vertical could be measured; on a second concentric circle the time of night could be read off.

Fig. 62.—A “night-dial.”

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[119] Dawn of Astronomy, 1894, p. 343.