 The construction could be carried on two wooden poles.A very similar setup was illustrated in 1645 in Athanasius Kircher's influential book "Ars Magna Lucis Et Umbrae".Around 1575 Italian Dominican priest, mathematician, astronomer, and cosmographer Ignazio Danti designed a camera obscura gnomom and a meridian line for the Basilica of Santa Maria Novella, Florence and he later had a massive gnomon built in the San Petronio Basilica in Bologna.