Stone-Age Scientific & Astronomical Instruments: Newgrange & Portuguese Burial Tombs Compared

A recent study proposed that the long passageways of Portuguese burial tombs were essentially the world's first telescopes. The long passageway at the passage tomb at Newgrange Ireland that is aligned with the winter solstice sunrise can also be considered another kind of Neolithic astronomical instrument. This paper compares the two designs and the similarity between them.