Re: sundial read from moonlight
Hi Donald I cannot help you with an article on that specific topic but there is a dial at Queens’ College Cambridge which has at its bottom a table of corrections to be used to tell time by the moon. An article published by the University (courtesy Drs Robin Walker and Frank King) is at http://www.queens.cam.ac.uk/page-241 It describes the dial and includes mention of the table and how it should be used. These corrections apply to all dials, not just to that at Queens’. I hope it helps; but I have to say that when even when you do make the requested corrections the resulting time may still be quite inaccurate! The moon’s motion is much more complicated than can be described by a few simple integers. Patrick From: Donald Christensen Sent: Sunday, July 31, 2011 1:14 AM To: f.w.m...@rug.nl Cc: sundial@uni-koeln.de Subject: Re: sundial read from moonlight Sorry I wasn't very clear with my question. I'd like to know how to read a horizontal sundial in the moonlight. I wish I could find the artical that I read on it. I'm going by memory so this is probably wrong but it went something like this: On a full moon, a horizontal dial reads correct. For each day after a full moon, 43 minutes must be addet to the time. Likewise, for each day before a full moon, 43 minutes must be subtracted to the time. On 7/31/11, Frans W. Maes f.w.m...@rug.nl wrote: Dear Donald, One can use the moon's shadow as long as it is distinguishable at night, say, one week either side of full moon. For an example, see: http://www.fransmaes.nl/genk/welcome-e.htm, choose menu item 7 and scroll down in the right-hand frame to The moon dial. Best regards, Frans Maes On 30-7-2011 10:23, Donald Christensen wrote: I heard that a sundial will read the correct time with the shadow on the moon on a certain day. (full moon?) -- Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: sundial Digest, Vol 67, Issue 52
. Patrick From: Donald Christensen Sent: Sunday, July 31, 2011 1:14 AM To: f.w.m...@rug.nl Cc: sundial@uni-koeln.de Subject: Re: sundial read from moonlight Sorry I wasn't very clear with my question. I'd like to know how to read a horizontal sundial in the moonlight. I wish I could find the artical that I read on it. I'm going by memory so this is probably wrong but it went something like this: On a full moon, a horizontal dial reads correct. For each day after a full moon, 43 minutes must be addet to the time. Likewise, for each day before a full moon, 43 minutes must be subtracted to the time. On 7/31/11, Frans W. Maes f.w.m...@rug.nl wrote: Dear Donald, One can use the moon's shadow as long as it is distinguishable at night, say, one week either side of full moon. For an example, see: http://www.fransmaes.nl/genk/welcome-e.htm, choose menu item 7 and scroll down in the right-hand frame to The moon dial. Best regards, Frans Maes On 30-7-2011 10:23, Donald Christensen wrote: I heard that a sundial will read the correct time with the shadow on the moon on a certain day. (full moon?) -- Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- 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/20110731/34e9890e/attachment.html -- ___ sundial mailing list sundial@uni-koeln.de https://lists.uni-koeln.de/mailman/listinfo/sundial End of sundial Digest, Vol 67, Issue 52 *** --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Azimuth calculation
Fellow dialists: I am using the following well known formula to calculate the sun’s azimuth for a particular time and location: Azimuth= tan-1(sin H/(sin φ*cos H – cos φ*tanδ) where H= Sun’s hour angle φ= the latitude - 42.3 degrees δ is the sun’s declination - 18.62 degrees The location is in Boston, USA or 42.3 degrees N and 71.04 degrees west I am using the azimuth-azimuth approach to find the declination of a wall found here: http://www.mysundial.ca/tsp/wall_declination.html the time the measurement was made was 11:18 am (daylight savings time is in effect) I can easily calculate that the azimuth with respect to the wall is 26.8 degrees. Here is the problem: using two other independent methods I find that the wall’s declination is 20 degrees East. So 26.8 degrees – Sun’s Azimuth should equal about twenty degrees. But, using the above equation I cannot get an Azimuth value to work. One place where I might be in error is the value of the Hour angle which I compute to be about –16 degrees. But you can also find the Hour Angle on line here at http://pveducation.org/pvcdrom/properties-of-sunlight/sun-position-calculator Where might I be going wrong? Many thanks for a reply! Andrew Theokas --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Azimuth calculation
Hi Andrew, have you correct H for the longitude and EoT? You may get a confirmation of your calculation with GnomoLab of Sundial Atlas. In www.sundialatlas.eu click GnomoLab in the right column. Click on the orange asterisk beside latitude to digit the coordinates. I use your data but they are not accurate enough to locate the building. Pan and zoom the map to get the building. With GnomoLab you can evaluate the declination of the wall, get the parameters of the dial and watch it with the shadow in real time. ciao Fabio Fabio Savian fabio.sav...@nonvedolora.it Paderno Dugnano, Milan, Italy 45° 34' 10'' N 9° 10' 9'' E GMT +1 (DST +2)attachment: gnomolab.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Azimuth calculation
Andrew: I think your numbers make sense. You didn’t mention the date, but I suspect your calculation was for July 30, 2011. For this date at 11:18 a.m. EDT, and the lat/long of Boston, I find the following values --- Sun’s declination: +18.5 degrees Sun’s azimuth:133.4 degrees (from north through east) When you say the wall “declination” is 20 degrees east (from due south), this is the same as saying that the normal to the wall faces azimuth 160 degrees (measured from north through east). Then, you measured the Sun’s azimuth to be 26.8 degrees (east) with respect to the wall, implying that the Sun’s azimuth is 160 – 26.8 = 133.2 degrees. This is rather close to the 133.4 that I got independently above. Some reference books define azimuths as the angle from due south, while others define it as the angle from true north, so it is important to keep these straight. Roger From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Andrew Theokas Sent: Sunday, July 31, 2011 9:57 AM To: sundial@uni-koeln.de Subject: Azimuth calculation Fellow dialists: I am using the following well known formula to calculate the sun’s azimuth for a particular time and location: Azimuth= tan-1(sin H/(sin φ*cos H – cos φ*tanδ) where H= Sun’s hour angle φ= the latitude - 42.3 degrees δ is the sun’s declination - 18.62 degrees The location is in Boston, USA or 42.3 degrees N and 71.04 degrees west I am using the azimuth-azimuth approach to find the declination of a wall found here: http://www.mysundial.ca/tsp/wall_declination.html the time the measurement was made was 11:18 am (daylight savings time is in effect) I can easily calculate that the azimuth with respect to the wall is 26.8 degrees. Here is the problem: using two other independent methods I find that the wall’s declination is 20 degrees East. So 26.8 degrees – Sun’s Azimuth should equal about twenty degrees. But, using the above equation I cannot get an Azimuth value to work. One place where I might be in error is the value of the Hour angle which I compute to be about –16 degrees. But you can also find the Hour Angle on line here at http://pveducation.org/pvcdrom/properties-of-sunlight/sun-position-calculator Where might I be going wrong? Many thanks for a reply! Andrew Theokas --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Inscribe please
I am getting several copies Only one for me at har...@shepherdswatch.com No others Harrismorrison Or configuration of gmail.com @somatic,cz Harris har...@shepherdswatch.com 514-487-5544 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Sundial read from moonlight
Hi Donald I cannot help you with an article on that specific topic but there is a dial at Queens’ College Cambridge which has at its bottom a table of corrections to be used to tell time by the moon. An article published by the University (courtesy Drs Robin Walker and Frank King) is at http://www.queens.cam.ac.uk/page-241 It describes the dial and includes mention of the table and how it should be used. These corrections apply to all dials, not just to that at Queens’. I hope it helps; but I have to say that when even when you do make the requested corrections the resulting time may still be quite inaccurate! The moon’s motion is much more complicated than can be described by a few simple integers. Patrick From: Donald Christensen Sent: Sunday, July 31, 2011 1:14 AM To: f.w.m...@rug.nl Cc: sundial@uni-koeln.de Subject: Re: sundial read from moonlight Sorry I wasn't very clear with my question. I'd like to know how to read a horizontal sundial in the moonlight. I wish I could find the artical that I read on it. I'm going by memory so this is probably wrong but it went something like this: On a full moon, a horizontal dial reads correct. For each day after a full moon, 43 minutes must be addet to the time. Likewise, for each day before a full moon, 43 minutes must be subtracted to the time. On 7/31/11, Frans W. Maes f.w.m...@rug.nl wrote: Dear Donald, One can use the moon's shadow as long as it is distinguishable at night, say, one week either side of full moon. For an example, see: http://www.fransmaes.nl/genk/welcome-e.htm, choose menu item 7 and scroll down in the right-hand frame to The moon dial. Best regards, Frans Maes On 30-7-2011 10:23, Donald Christensen wrote: I heard that a sundial will read the correct time with the shadow on the moon on a certain day. (full moon?) -- Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Passion - Shall we change this to End of Life Plans?
Hi Warren: I have always loved the idea of deceased sundial society members and their families who donate their sundial stuff to their sundial society either as a gift or to be auctioned off for a worthy cause. Often their families could care less about these things, yet they want them to go to somebody who would appreciate having them. p.s. Since I regard the number of tatoos a body has as being inversely proportional to the person's IQ, I doubt that any members of the distinguished Sundial List have many tatoos- even sundial ones! -Original Message- From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Warren Thom Sent: Saturday, July 30, 2011 6:06 AM To: Sundial; Brent Subject: Re: Passion - Shall we change this to End of Life Plans? Over the last two weeks, I have given a little thought to having my parent's tombstone modified to include a sundial. It faces East and a few designs would look nice. (I have also spent several hours reading about cutting in stone that John Carmichael and others have so interestingly promoted.) On the appropriateness of the topic: Our minister gave a service one time on death. The focus was on making plans, not on the afterlife. She made a planning form available. It included hymns for a memorial service and other wishes. Some in the congregation thought it was inappropriate and some thought it practical. No one thought it was funny. Well she gave a few culturally used synonyms for death like, kick the bucket, sell the farm etc. that drew a few chuckles. With many different cultures represented on this list and the limits of expression in the written word, reading the list requires that we not make hasty assumptions about others intentions. I interpreted the questions below to be about personal plans and actions resulting from our unique interest. I assume the best of intentions unless proven otherwise with expanded discussion. The question of what to do with an accumulation of sundial items is a good one. Some items have value only to a few people. Since I plan to be cremated, I don't really want a dialing item to be destroyed. I mentioned this question very briefly at a NASS meeting either last year or the year before. I don't recall the outcome. I do plan to leave my intentions with my wife or children including the desire to sent some of the items to NASS to be given away in the silent auction. Are there other plans that others would share on the list? No tattoos for me. I have more than enough distinguishing marks on my body already and none are tattoos. Warren Thom (42 N, 89 W) Do any of you plan to have a sundial on your gravestone? Do any of you plan to be buried with a sundial? Do any of you have a sundial tattoo? -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
