Multispectral Imaging Shows Erased Evidence Of Ancient Star Catalogue

Ancient Greek astronomer Hipparchus worked to accurately catalog and record the coordinates of celestial objects. But while Hipparchus’ Star Catalogue is known to have existed, the document itself is lost to history. Even so, new evidence has come to light thanks to patient work and multispectral imaging.

Hipparchus’ Star Catalogue is the earliest known attempt to record the positions of celestial bodies (predating Claudius Ptolemy‚Äôs work in the second century, which scholars believe was probably substantially based on Hipparchus) but direct evidence of the document is slim. Continue reading “Multispectral Imaging Shows Erased Evidence Of Ancient Star Catalogue”

Historical Hackers: Ctesibius Tells Time

People are obsessed with the time and the weather. We’ve talked about the weather since we were all cave dwellers hunting with spears. But the time is a different matter. Sure, people always had the idea of the passage of time. The sun rising and setting gives a natural sense of days, but daylight and dark periods vary by the time of year and to get an accurate and linear representation of time turns out to be rather difficult. That is unless you are a Greek engineer living in Alexandria around 250 BC.

Legend has it that and engineer working in his father’s barbershop led him to discover not only the first working clock, but also the pipe organ, launching the field of pneumatics in the process. That engineer was named Ctesibius and while his story is mostly forgotten, it shows he has a place as a historical hacker.

You might think there were timekeeping devices before 250 BC, and that’s sort of true. However, the devices before Ctesibius had many limitations. For example, a sundial can tell time, but only if the sun is shining. At night or during a storm it is worthless.

Continue reading “Historical Hackers: Ctesibius Tells Time”