Frequently, when working on my astronomical research, I come up with interesting ideas for projects that I would love to tackle, but simply don’t have the time or may not have particular skillset to dive into. This post is intended to be a list of those ideas.
Copperplate Engraved Star Maps
The Uranometria (1603) was the first truly scientific star map. While there were many others before, they did not plot the stars based on their celestial coordinates and instead were simply artist renditions. Using the stellar positions I have collected, this work could be recreated.
Cosmological Arguments
While the mathematical astronomy I have studied is a major portion of astronomy in period, I have largely ignored the more philosophical side of things (often referred to as cosmology). This is things like the arguments of the position of the Earth in the cosmos, whether it rotates, etc… I only touch on these when Ptolemy comments on them, but there is a far richer dialogue through period addressing these questions. The book, Planets, Stars & Orbs: The Medieval Cosmos, 1200-1687 traces this history. I think it would make an entertaining class to read through this, select some arguments, and present them as a debate between the natural philosophers.
Modern Star Alignments
At the beginning of Book VII of the Almagest, Ptolemy talks about many of the stellar alignments reported by Hipparchus and himself. This is done by holding a taught string up to the sky and seeing what stars fall along that straight line. By comparing these alignments over long intervals, Ptolemy believed he would be able to discern whether or not the stars moved on the celestial sphere. This would be a simple process to reproduce and attempt to discern whether or not this method is sensitive enough to discern proper motion over a period of ~2,000 years. It would also serve as an excellent introduction to the night sky.
Translating the Aratus Latinus
One of the important texts throughout the middle ages was the Aratus Latinus. This Latin text was primarily based on Aratus’ Phaenomena, but also included fragments of other astronomical texts.
However, this important text has never received an English translation. A copy of a revised version of this text is available here should anyone desire to offer a translation.
Revisiting Ptolemy’s Location of the Milky Way
In VIII.2, Ptolemy gives a description of the stars that bound the milky way. My post examined this using Stellarium and other online resources, but this could also be investigated observationally from a sufficiently dark sky location.
Revisiting II.10’s “inscribed square”
Back in II.10, there was a statement that Ptolemy made regarding the radius of a circle he draws as being equal to the “side of the [inscribed] circle.” I have never been able to determine what this is supposed to mean.
One reader suggested that this might relate to a statement from II.6 where Ptolemy described the small circle traced out by the observer’s zenith each night. There, he describes that small circle as having a “radius” equal to the altitude of the celestial pole for the observer. In this case, it’s obvious that he’s using “radius” as an angular distance measured along the great circle through the pole, i.e., an angular distance.
I don’t think this applies to the situation in II.10 because the units of a side of an inscribed square would be in parts – a linear distance. Thus I don’t think the situations are analogous. However, this did cause me to return to this unresolved issue and wonder what inscribed square Ptolemy could referring to. Certainly not a square inscribed in a great circle since the length of its side would be longer than the radius, and thus any circle with that length as a radius could no longer be on the surface of the sphere! So what is Ptolemy trying to state here?
Evolution of the Astrolabe
In doing some other research, I stumbled on John Philoponus – a $6^{th}$ century philosopher who wrote the oldest known treatise on the astrolabe. How does the creating, function, and use differ from later treatises?
Under Explored Hebrew Texts
A little known Jewish astronomer is Rabbi Abraham bar Hiyya who wrote two works on astronomy in the 12th century: Tsurat ha-arets and Luhot ha-Nassi. These texts have not been translated from Hebrew.