Hi Brad, My message re your interest in hemicyclia should have made it clear that it was Fer De Vries’s original work on the construction of a Hemispherium that he placed on his website and which was republished after his death by Frans Maes and then placed on his own website for us to read today. My sincere apologies to Frans!
Patrick From: Patrick Powers Sent: Sunday, October 22, 2017 12:40 PM To: Brad Thayer ; sundial@uni-koeln.de Subject: Re: Hemicyclium correction Hi Brad Further to your interest in an hemicyclium you might like to know of this link to the former webpages of the late Frans Maes who set out his instructions for “Construction of Hemispherium” some time ago and which is based on several earlier documents – all referenced. You might find it useful – or at least interesting! http://www.fransmaes.nl/zonnewijzers/downloads/hemisph.htm Good luck Patrick From: Brad Thayer Sent: Monday, October 16, 2017 1:48 PM To: sundial@uni-koeln.de Subject: Hemicyclium correction I am looking to make a hemicyclium-type sundial (half-hemisphere) in a metal working class. What little I can find on them says they are inaccurate, without being very clear on the problem. It appears to me the only issue is it needs to be tilted so that the gnomon aligns with the Earth’s rotation axis; thus the half-bowl faces south and the gnomon points south, but the end of the gnomon that attaches to the bowl points north. Am I missing anything? I am also looking to use an analemma-shaped gnomon to cast the shadow on the bowl, and at least month lines for the solar elevation. The bowl will also have a rod and bracket on the bottom to allow it to be rotated for daylight-savings time and for local longitude corrections. Thanks in advance -- Brad -------------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
