Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die eigentliche Nachricht steht dadurch in einem Anhang.
This message was wrapped to be DMARC compliant. The actual message text is therefore in an attachment.
--- Begin Message ---Hi Bred, Initially, hemishpere was used by Shumer's priests for astrology reasons, as an oriented model of anti-firmament with polos (movable ghomon in the form of armillary) to get some ephemeris. Polos had an adjustuble scale for Sun's declination according to twelve Nippur Zodiac signs. The idea was degraded (with the help of the theacher of Alexander the Great, - Aristotel ;) by fixing a vertical gnomon with top in the center of hemisphere. Nowdays, you have to adjust any such constract to polar style - marking and positioning. It will be as accurate, as Sun is. Best wishes in sundialing, Alexei Krutiakov www.analemma.ru >Вторник, 17 октября 2017, 13:01 +03:00 от sundial-requ...@uni-koeln.de: > >Send sundial mailing list submissions to >sundial@uni-koeln.de > >To subscribe or unsubscribe via the World Wide Web, visit >https://lists.uni-koeln.de/mailman/listinfo/sundial >or, via email, send a message with subject or body 'help' to >sundial-requ...@uni-koeln.de > >You can reach the person managing the list at >sundial-ow...@uni-koeln.de > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of sundial digest..." > > >Today's Topics: > > 1. Hemicyclium correction (Brad Thayer) > 2. Re: Hemicyclium correction (Frank King) > 3. Great Circle Studio Solar Calculator - again! (Patrick Powers) > 4. Re: Great Circle Studio Solar Calculator - again! > (????????? ????????) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Mon, 16 Oct 2017 08:48:18 -0400 >From: "Brad Thayer" < wissenschaft...@verizon.net > >To: < sundial@uni-koeln.de > >Subject: Hemicyclium correction >Message-ID: < 03ca01d3467d$0a7ff290$1f7fd7b0$@verizon.net > >Content-Type: text/plain; charset="us-ascii" > >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 > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: < >https://lists.uni-koeln.de/mailman/private/sundial/attachments/20171016/5a3728ae/attachment-0001.html > > > >------------------------------ > >Message: 2 >Date: Mon, 16 Oct 2017 16:12:15 +0100 >From: Frank King < f...@cl.cam.ac.uk > >To: "Brad Thayer" < wissenschaft...@verizon.net > >Cc: sundial@uni-koeln.de, Frank King < f...@cl.cam.ac.uk > >Subject: Re: Hemicyclium correction >Message-ID: < e1e473y-0007r9...@mta1.cl.cam.ac.uk > >Content-Type: text/plain; charset=us-ascii > >Dear Brad, > >You say: > >> I am looking to make a >> hemicyclium-type sundial >> (half-hemisphere) in a >> metal working class. > ><snip> > >> Am I missing anything? > >Er, yes. Rather a lot alas... > >Before you start bashing metal >it may be worth spending rather >less effort on a prototype. > >> ...they are inaccurate... > >I am not sure where you got that >from. There is no reason why they >shouldn't be accurate provided you >know what you can expect of one. > >> ...without being very clear >> on the problem. > >I suspect the writer of your >quote either didn't know what a >hemicyclium was or had looked >at one and noted that it didn't >indicate the same time as his >watch so it must be wrong. > >> It appears to me the only >> issue is it needs to be >> tilted so that the gnomon >> aligns with the Earth's >> rotation axis... > >Er, no. The polar-oriented >gnomon wasn't invented for >nearly 1500 years after the >hemicyclium was in common >use. > >What looks like a gnomon and >may well be CALLED a gnomon >is not what you think of as >a gnomon. It is actually >a "nodus support". Only >the shadow of the tip is >of interest. > >> I am also looking to use >> an analemma-shaped gnomon >> to cast the shadow on the >> bowl... > >First, build a prototype. >You can think about fancy >upgrades later. > >Imagine the following... > > 1. Take an orange. > > 2. Cut it in half. Throw > one half away. [OK, > maybe eat it first.] > > 3. Then cut the half > in half and throw > one of these quarters > away. > > 4. What you are left with > is your half hemisphere. > > 5. This has one curved > surface and two plane > surfaces. > > 6. Arrange for one of the > planes to be horizontal > and the other to be > vertical and facing > due south (assuming you > are in the northern > hemisphere). > > 7. Now place a bead in the > middle of the edge that > is common to the two flat > faces. THIS is the nodus. > > 8. Now imagine that all the > space between the bead > and the skin is replaced > by a transparent medium. > > 9. You now have an embryonic > hemicyclium. Let's think > about some of its > properties.... > >10. At sunrise (and sunset) > the sun is in the plane > of the horizontal flat > surface, and the shadow of > the bead (in the winter > half of the year) will > fall on the inside rim > of the horizontal element > of skin. This rim is the > "horizon line". > >11. At an equinox the shadow > of the bead during the > course of a day will > follow a great (half) > circle on the inside > surface of the skin. > >12. At the winter solstice > it will follow a small > (less than half) circle > on the inside surface > and this will be above > the equinoctial circle. > >13. At the summer solstice > you hit a minor snag. > At sunrise the sun is > north of due east and > the shadow of the bead > will not fall on the > rim. Don't worry about > this yet. [The Greeks > DID cope with this but > that's for later.] > >14. Instead, pick up the > path of the shadow > starting from when the > sun is due east and, > by then, some way > above the horizon. > >15. You will again get a > small (less than half) > circle. > >16. Now add lots of > intermediate small > circles for other > times of year. > >17. At this point you have > a choice as to how you > chop up each circle into > hours... > >18. The ancients chopped each > part circle in the winter > half into 12 parts, thus > dividing the daylight > period into unequal hours. > You could label the spaces > 1 to 12 if you like. The > Greeks didn't have digits > or even Roman Numerals and > labelled the hours alpha, > beta, gamma etc. > >19. That's the way I would do > it but if you insist on > using iconoclastic new > fangled equal hours then > you can. You will find > it rather harder! > >20. That completes your > prototype. Now have a > long think about what > you really want to do. > >Very best wishes > >Frank > >Frank H. King >Cambridge, U.K. > > > > >------------------------------ > >Message: 3 >Date: Mon, 16 Oct 2017 21:16:28 +0100 >From: "Patrick Powers" < patrick_pow...@compuserve.com > >To: "Sundial mail list NEW" < sundial@uni-koeln.de > >Subject: Great Circle Studio Solar Calculator - again! >Message-ID: <35CEDB9248504C75945AE266ABCBEAE6@PatrickPC> >Content-Type: text/plain; charset="windows-1252" > >Hello to all those interested in the currently defunct Great Circle software. >I have managed to make contact with the designer of the Great Circle Studio >Solar Calculator and mentioned that it does not seem to work. His reply >tonight tonight is: >----- >Hi Patrick, >Thank you for your e-mail. I'm afraid that got broken when I updated my >server. I'll take a look and get it fixed. >Thanks again... >---- >Maybe we can hope? If I hear more I shall report it here. > >Regards > >Patrick >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: < >https://lists.uni-koeln.de/mailman/private/sundial/attachments/20171016/e61b48f0/attachment-0001.html > > > >------------------------------ > >Message: 4 >Date: Mon, 16 Oct 2017 23:41:05 +0300 >From: ????????? ???????? < sundi...@mail.ru > >To: Patrick Powers < patrick_pow...@compuserve.com > >Cc: Sundial mail list NEW < sundial@uni-koeln.de > >Subject: Re: Great Circle Studio Solar Calculator - again! >Message-ID: < 1508186465.3039...@f435.i.mail.ru > >Content-Type: text/plain; charset="utf-8" > >Thank you very much, Patrick. >This is encouraging news. >The program was very useful. >I hope we all will be lucky to receive a correction! >Aleks > > >>???????, 17 ??????? 2017, 0:16 +04:00 ?? "Patrick Powers" < >>patrick_pow...@compuserve.com >: >> >>Hello to all those interested in the currently defunct Great Circle >>software. >>I have managed to make contact with the designer of the Great Circle Studio >>Solar Calculator and mentioned that it does not seem to work.? His reply >>tonight tonight is: >>----- >>Hi Patrick, >>Thank you for your e-mail. I'm afraid that got broken >>when I updated my server. I'll take a look and get it fixed. >>Thanks again... >>---- >>Maybe we can hope?? If I hear more I shall report it here. >>Regards >>Patrick >>--------------------------------------------------- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> > > > >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: < >https://lists.uni-koeln.de/mailman/private/sundial/attachments/20171016/17d385ae/attachment-0001.html > > > >------------------------------ > >Subject: Digest Footer > >_______________________________________________ >sundial mailing list >sundial@uni-koeln.de >https://lists.uni-koeln.de/mailman/listinfo/sundial > > >------------------------------ > >End of sundial Digest, Vol 142, Issue 7 >***************************************
--- End Message ---
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
