|This article is of interest to the following WikiProjects:|
I'm confused by the phrase, "it was obsolete as an astronomical instrument, having been replaced by the armillary sphere". IIUC, the armillary sphere was a teaching/study tool, while the dioptra was a measuring tool, something like a theodolite without optics. If I thought I knew what I was talking about, I'd rip it out. Wcoole (talk) 22:20, 5 November 2008 (UTC)
- I wrote that line. I got it from James Evans: The History and Practice of Ancient Astronomy, page 35: "However, by the time of Hipparchus (second century BC), the dioptra was replaced by the armillary sphere as the instrument of choice for measuring the positions of the stars. From then on, the dioptra's chief role in astronomy was that of a demonstration device or teaching tool." Concerning the armillary sphere, he says on page 80: "if an armillary sphere is made well enough, and large enough, and equipped with sights, it can also function as an instrument of observation. It can be used, for example, to measure the celestial coordinates of stars or planets in the night sky. By Ptolemy's time, the armillary sphere had become the preferred instrument of the Greek astronomers." Singinglemon (talk) 20:14, 9 November 2008 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Dioptra. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
- Added archive https://web.archive.org/web/20051211215037/http://www.mlahanas.de/Greeks/HeronAlexandria.htm to http://www.mlahanas.de/Greeks/HeronAlexandria.htm
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
You may set the
|checked=, on this template, to true or failed to let other editors know you reviewed the change. If you find any errors, please use the tools below to fix them or call an editor by setting
|needhelp= to your help request.
- If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
- If you found an error with any archives or the URLs themselves, you can fix them with this tool.
If you are unable to use these tools, you may set
|needhelp=<your help request> on this template to request help from an experienced user. Please include details about your problem, to help other editors.