310 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1964 



Aiid as I pondered, the sun kept rising. And it was rising almost 

 horizontally, so that it had traveled fully 2 degrees before the disk 

 stood clear of the horizon. That meant that it would be — would have 

 been — extremely difficult to estimate the exact spot at which it lifted 

 clear of the horizon. Clouds, of course, are common in England, and 

 the Stonehenge people were probably no more fortunate than the 

 modern Briton. Nowadays I think only one in five Midsummer sun- 

 rises at Stonehenge is clear. All of these things would make the set- 

 ting of the stones difficult. Critical conditions, devices capable of 

 precise measurement, evidence of knowledge, skill, purpose — all for 

 what? 



I thought, in that lonely place: "Was Stonehenge an observatory?" 



There seemed to be significance in those delicate alinements, and it 

 would most logically be astronomical significance. What would you 

 line sighting-stones on ? Surely on the heavenly bodies — the gods of 

 prehistory and so-called barbarism. The center-heelstone certainly 

 pointed to Midsummer sunrise; could there have been other such 

 alinements, such as a corresponding one pointing to Midwinter sunset ? 

 I read at Stonehenge that the noted British archeologist E. S. Newall 

 had suggested that possibility, but there had been no verification. 

 What did those alinements point to ? 



I said to myself, "It's no good just talking. The problem is too 

 complicated. We need precise measurement, more elaborate calcula- 

 tion that I am prepared to do. We need the machine." But at that 

 moment, I had more mundane problems to face — the barbed wire fence, 

 the hotel bill, and an English summer squall that was dashing cold 

 rain across the plain. 



WHAT THE COMPUTER SAID 



Before I left England I got plans and charts of the site. Back in 

 Cambridge, Mass., I armed myself with all the pertinent material in 

 Harvard's Widener Library. I defined the problem: What^ if any^ 

 correlation is there hetiveen Stonehenge alinements and the rise or set 

 points of any heavenly bodies, as of the period 2000-1500 B.C.? Then 

 with the help of Shoshana Rosenthal and Judy Copeland at the 

 Smithsonian Astrophysical Observatory, I went to the machines. 



First we put charts of Stonehenge into "Oscar," a plotting machine 

 that transforms positions into X, Y coordinates on punched cards. 

 Then we fed those coordinates into the Harvard-Smithsonian IBM 

 7090 computer and asked it to calculate azimuths, or compass direc- 

 tions, determined by some 170 pairs of positions, a position being a 

 stone, stone hole, mound, archway, or the center. Next we asked the 

 machine to translate those azimuths into declinations, that is, to deter- 

 mine the "latitudes" of the celestial sphere they intersected. 



