tag:blogger.com,1999:blog-7752626037671660516.post1386219940328138268..comments2021-01-20T09:22:07.084+00:00Comments on Astrolabes and Stuff: Leap years and astrolabesSeb Falkhttp://www.blogger.com/profile/12749635113622688649noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-7752626037671660516.post-76611847698226449702016-04-29T20:51:06.456+01:002016-04-29T20:51:06.456+01:00Thank you very much for your quick reply! Both Joh...Thank you very much for your quick reply! Both John North and Chaucer's Universe look like great resources-- I'll have to track them down somehow :) The main resource I've used so far is James Morrison's Astrolabe book, which is pretty systematic. 14th C is pretty early for most western astrolabe systems, so tracking down resources has been challenging.<br /><br />Thank you again for your help; I look forward to seeing more posts on your page in the future :)<br /><br />-VitalyVitalynoreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-8820593613435719312016-04-22T02:25:33.068+01:002016-04-22T02:25:33.068+01:00I've arrived at the realization that both my e...I've arrived at the realization that both my ecliptic and peripheral date scale need to be adjusted for proper position in each of the four leap year cycles. To me the best way to do this is to produce four star maps, each with the appropriately positioned date and ecliptic scale. The trick then is to make them easily interchangeable. Again, we can do this because we're not working in brass! This eliminates the clear overlay for the ecliptic.Tim Stonehttp://flickr.com/photos/timstonenoreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-44185040802725251232016-04-21T05:22:10.390+01:002016-04-21T05:22:10.390+01:00Glad you like it! I'm on holiday at the moment...Glad you like it! I'm on holiday at the moment so only time for a quick reply, but the absolute best book on medieval astrology is "Horoscopes and History" by John North. It's hard to find, but worth the effort, and will tell you loads about medieval house systems. North's work also covers astrolabes (there's a great explanation of how they worked in "Chaucer's Universe"), but once you've mastered the functions (which it sounds like you have), I'd say the best thing is just to look at lots of examples (I can't think of any book that systematically compares different astrolabe layouts). http://www.mhs.ox.ac.uk/astrolabe/ is a good catalogue with great images, if you've not already found that. Good luck!Seb Falkhttps://www.blogger.com/profile/12749635113622688649noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-27993125042724802622016-04-21T00:45:08.528+01:002016-04-21T00:45:08.528+01:00Cool website! I'm in the design phase of a 14t...Cool website! I'm in the design phase of a 14th-century-style astrolabe, so I would love to hear more about medieval house systems! Everything I've seen only goes back to Regiomontanus. Is there a good bibliography you could recommend for 14th century sources on astrology or astrolabes?<br /><br />Thanks again for the website and, in advance, for your consideration! :)Vitalynoreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-46373632970112136882016-04-03T20:43:31.436+01:002016-04-03T20:43:31.436+01:00Very interesting! I think transparent overlays ha...Very interesting! I think transparent overlays have real potential to do things that couldn't be done with brass. It can be fiddly to change them around, but then you could say the same about the latitude plates that were very common. I hope you manage to find a solution that works for you!Seb Falkhttps://www.blogger.com/profile/12749635113622688649noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-81803504036414028582016-04-03T20:33:29.971+01:002016-04-03T20:33:29.971+01:00Oh yes! A lot of people are surprised to find Cha...Oh yes! A lot of people are surprised to find Chaucer wrote a treatise on the astrolabe, but it was very popular (it survives in more than 30 manuscripts). In fact the "Equatorie of the Planetis" manuscript, which I've been researching, cites Chaucer's Treatise on the Astrolabe and was obviously influenced by Chaucer's approach. <br /><br />There's no contradiction between Chaucer the poet and Chaucer the astronomer. His preface, where he lays out the plan of his writing and explains why he was writing in English instead of Latin, is always worth a read, and the treatise as a whole is still a clear and readable guide to the astrolabe, more than 700 years after it was written. (You can find it online at http://www.chirurgeon.org/treatise.html.)Seb Falkhttps://www.blogger.com/profile/12749635113622688649noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-80291048285456321782016-04-03T15:25:33.054+01:002016-04-03T15:25:33.054+01:00I'm sure you've come across this---But jus...I'm sure you've come across this---But just in case you haven't (I was so {unscientifically} tickled to find it, myself): Tractatus de Conclusionibus Astrolabii, Geoffrey Chaucer <br /><br />Lyte Lowys my sone, I aperceyve wel by certeyne evydences thyn abilite to lerne sciences touching nombres and proporciouns; and as wel considre I thy besy praier in special to lerne the tretys of the Astrelabie. Than for as moche as a philosofre saith, “he wrappith him in his frend, that condescendith to the rightfulle praiers of his frend,” therfore have I yeven the a suffisant Astrolabie as for oure orizonte, compowned after the latitude of Oxenforde; upon which, by mediacioun of this litel tretys, I purpose to teche the a certein nombre of conclusions aperteynyng to the same instrument.<br /><br /><br />secretgardenerhttps://www.blogger.com/profile/15650883324027210560noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-71130680844914296632016-03-16T04:11:08.662+00:002016-03-16T04:11:08.662+00:00I've placed the ecliptic right on the planisph...I've placed the ecliptic right on the planisphere star map, which makes showing multiple years solar positions problematic. The Merton solution was to mark the solar position on the perimeter, which in my case would require a straight edge from the pivot to the perimeter to find the solar position. But I want to be able to, for example, place the solar position on the planisphere's horizon, to predict local sunrise/sunset. This would be inconvenient with a straight edge.<br /><br />I tried creating tick marks on the ecliptic to show the solar position in each of the leap year cycle years. That was horrible. I couldn't figure out which set of tick marks I should use, and I'm the one that created them. I figured anyone else would be hopelessly lost.<br /><br />So, I'm considering moving the ecliptic to a transparent overlay that can be fixed to the planisphere sky map. This would allow me to print one for each of the leap year cycle years. It's less convenient for sure, but allows me to predict the solar position/altitude directly on the ecliptic.<br /><br />Ugh! I've spent far more time on the ecliptic than I did on the remainder of the planisphere! Check https://flic.kr/p/ETxePbTim Stonehttps://flic.kr/p/ETxePbnoreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-67424652954183938682016-03-06T13:47:17.405+00:002016-03-06T13:47:17.405+00:00Thanks! I'd be interested to hear how you get...Thanks! I'd be interested to hear how you get on (and see pictures). I love your photos, by the way!Seb Falkhttps://www.blogger.com/profile/12749635113622688649noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-72137411839116321492016-03-06T04:45:05.627+00:002016-03-06T04:45:05.627+00:00This is a great article! I recently created my own...This is a great article! I recently created my own planisphere, and wrestled with the same question. I settled on the middle year solution, but found it a bit unsatisfactory. I'll have to see if I can adapt the Merton concept. Thank yoU!Tim Stonehttp://flickr.com/photos/timstonenoreply@blogger.com