Al-Biruni's diagram of the moon's phases.
Credit: photo reproduction from Seyyed Hossein Nasr, Islamic Social Science: An Illustrated Study (World of Islam Festival Publishing Co., 1976).
Photo use for non-profit educational purposes only.
Ibn al-Shatir, whom we give credit for inventing the first modern sundial with gnomon pointing to the celestial pole in 1371 C.E., is but one of many scientific scholars of Central Asia during the “Eastern Renaissance” that lasted from about 800 to 1500 C.E. In this week’s issue of Science, [20 June 2014] Richard Stone reviews the accomplishments of Abu Rayhan al-Biruni (born 973 C.E.) and the possibility that he "discovered" the American continent.
Situated at the crossroads of cultures from China, India, the Middle East, and Europe, al-Biruni was an acomplished astronomer at an early age. At 16 he measured the height of the midday sun and calculated the latitude of his hometown, now in present day Khiva, Uzbekistan.
[photo Courtesy University of Basel]
Professor Dr. Susanne Bickel and her archeological team from the University of Basel found one of the oldest sundials in the world during this year’s excavation in the Valley of the Kings. A limestone sundial was found near tomb KV61 during a survey of the surface rubble. The location of the dial corresponds to an area where there are remains of workmen’s huts dating to the Ramesside Period of the 13th century BCE.
The dial was most likely a vertical, south facing sundial. The horizon line of the dial is about 16 cm across with a hole at the mid point to hold a simple horizontal metal rod or wood stick gnomon, indicating that the gnomon displayed shadows of temporal (seasonally uneven) hours. The limestone dial has a black painted semicircle. On each side of the vertical noon line are 6 segments of about 15 degrees each, representing morning and afternoon temporal (seasonally uneven) hours. Small dots in the middle of each hourly segment serve for even finer timing. Nevertheless, the hour lines are not drawn with precision.
At 3pm on August 15th Roger Bailey of the North American Sundial Society will hold a public lecture on the historic Ibn al-Shatir sundial at the Great Falls Library in VA. The Analemma Society proposes to recreate the dial’s design, adapted for the latitude of Observatory Park, The Turner Farm, in Great Falls, VA.
Hopefully this will be the second major dial at Observatory Park maintained by the Analemma Society in conjunction with the Fairfax County Park Authority. The first dial was a commemorative dial designed and built by Tony Moss for the 400th anniversary of Jamestown, VA.
“High on the minaret of the Great Mosque in Damascus is a remarkable sundial created by Ibn al-Shatir in 1371. Through the 10th to 14th centuries the science of astronomy, timekeeping and sundials had advanced in major Moslem centres like Cairo and Damascus. Based on the developing science of timekeeping, Ibn al-Shatir designed a unique instrument that was a breakthrough…The sundial features equal hours rather than the previous system of dividing the day into 12 hours regardless of the seasonal changes.”
Gardom Edge Monolith
[photo courtesy of Dan Brown, Nottingham Trent University]
A two meter standing stone at Gardom’s Edge may be an astronomically aligned monolith set up during the Neolithic period 2,500 – 1,500 BCE to recognize the summer solstice. According to Dan Brown, Andy Alder and Elizabeth Bemand of Nottingham Trent University, “Such an astronomically aligned stone could be described as a seasonal sundial … However it is not intending to mark local time during a day or measure exact dates during a year. Rather the seasonal shadow casting allows for the display of cosmological knowledge such as the ‘death’ and ‘rebirth’ of the Sun”…
The upward facing north slope of the stone remains in shadow until near the time of Summer solstice. Today the stone points south at an upward tilt of 58.3° +/- 2.9°, seemingly aimed at the highest rise of the summer sun, computed for the Gardom Edge latitude of 53.26° as 60.7° in Neolithic times.
One of the most iconic buildings in the world, the Pantheon in Rome is an enduring testament to the power and glory of ancient Rome. At the same time, it has also always posed something of a mystery. The only source of natural lighting is a thirty-foot diameter hole at the very top of the hemispherical dome, often referred to as the "oculus".
Working since 2009, scholars Guilio Magli and Robert Hannah discovered that at midday on the equinoxes, a shaft of circular light shines through the oculus and illuminates the Pantheon's entrance.
[photo credit: Andrew Caswell and
Robert Cockburn of The Daily Telegraph ]
Ask a person what is the earliest evidence of humans building structures to mark significant celestial events, and one offer "Stonehenge". But there may be a structure built thousands of years early according to some experts in Australia.
A site "down under", name Wurdi Youang, estimated to be older than 10,000 years, has a strange arrangement of stones with alignments toward solstices and equinox that has been scrutinized by several eminent Australian scientists. They conclude that the placement and alignment of the stones is not an accident and there is a perfect alignment with the setting sun on the mid-summer day. Understandably, the exact location of the site is a well-guarded secret, but it is known to be west of Melbourne approximately 80 kilometers.