Re: Is it possible to determine when the sun is due East & West?

[fer de vries]

Re: Is it possible to determine when the sun is due East & West?   I wanted to answer to this thread and I needed a figure. My e-mail to the sundial list didn't pass so I offer my answer for download at: http://www.de-zonnewijzerkring.nl/test/mekka.htm Together with a second figure the file is about 370 kB. Best wishes, Fer Fer J. de Vries De Zonnewijzerkring mailto:[EMAIL PROTECTED] http://www.de-zonnewijzerkring.nl Eindhoven, Netherlands lat.  51:30 N      long.  5:30 E ----- Original Message ----- From: "David Lawrence" <[EMAIL PROTECTED]> To: <sundial@rrz.uni-koeln.de> Sent: Friday, September 16, 2005 10:44 AM Subject: Is it possible to determine when the sun is due East & West? > > At first sight, this looked like a 'trivial' request - but it very > quickly became apparent that I don't have enough knowledge, and so > I have joined this mailing-list in the hope of getting help from > people who may be more able to say whether it is even possible! > > I am located in Northern Ireland, and (knowing of my hobby-level > interest in Amateur Astronomy) - I was recently asked if it would > be possible to tell the exact time when the sun is DUE EAST & WEST. > > There is a local group of Muslim 'asylum-seekers', who have been > moved here from mainland Britain - and (as part of their religious > observance duties), they want to arrange prayer sessions whenever > the sun is precisely in both the due East and due West directions. > > Initially, I thought "Easy - just have a vertical stick (or any > simple 'nodus'), with some North/South/East/West markings on the > ground, and they can watch the shadow until it shows that time". > > However, two problems - (1) What if it is not sunny, and (2) Even > if it is sunny, what would they do during the Winter period, when > the sun will rise/set without reaching the East/West directions? > > My next thought was "OK, it should be possible to use a computer > program to calculate the times, for every day of the year" - BUT > the Muslim group will not accept any form of 'modern technology' > for this task, and insist that it must be done either by direct > observation or obvious mechanical means (apparently some type of > simple 'clockwork' will be OK for them, but nothing electronic). > > My question is therefore "Can the moment when the sun is exactly > due East or West be determined, in any way which will satisfy this > 'fundamentalist' Muslim group - or is it an impossible request? > > Any thoughts or suggestions from members will be much appreciated. > > Sincerely, > > David Lawrence. > > > -- > -