On the Spanish coal mine
Dear all, I've read Rogelio Menendez article on the 'Mile' Mine in Bembibre (Spain) and I can make a small summary of it for these (few!) of you that do not understand Spanish. Rogelio is a geologist working for a mining company and he reports of a now abandoned coal mine that consists of a 742 meter long and 2*2 meter wide tunnel. Interestingly the tunnel is completely straight, having an inclination of 19 deg and an azimuth (from N) of 75 deg so that the sun reaches the bottom of the mine well twice a year, on March 25 and Sept 26. He says that is quite uncommon in mining having such kind of gallery, and generally speaking there aren't many tunnels so long in the world exhibiting so a phenomenon, perhaps being the most known the one in Abu Simbel. Is that right? Do you know of other constructions like this? Do you think it is worthwile keeping it as a didactical issue? I do not know if it is safe to take children to the bottom of a coal mine but indeed it'd be quite astounding for them seeing the Sun lighting the whole tunnel in a few seconds twice a year. Regards, Anselmo --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Terminator
I have a site on my browser, www.mapmaker.com/shadowfacts/sunweb.asp that shows the terminator throughout the year. It is fascinating to see how rapidly the shape changes, and I was astonished to see this evening that it is nearly a straight line, as we approach the equinox. Of course, a little thought shows that I have should have expected this, but to see it on a 'flat earth' reminds one of what is happening to a globe, or the earth itself. I expect others have more fun with other representations! Doug --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Terminator
Thank you Doug, Another one very different but interesting too on the equinox day, have a look on my favorite sundial, in the South of France http://perso.wanadoo.fr/cadrans.solaires/cadrans/cadran-mines.html Joël 48°01'25'' N, 1°45'40 O http://www.cadrans-solaires.fr/ - Original Message - From: Douglas Bateman [EMAIL PROTECTED] To: sundial@uni-koeln.de Sent: Sunday, March 19, 2006 7:01 PM Subject: Terminator I have a site on my browser, www.mapmaker.com/shadowfacts/sunweb.asp that shows the terminator throughout the year. It is fascinating to see how rapidly the shape changes, and I was astonished to see this evening that it is nearly a straight line, as we approach the equinox. Of course, a little thought shows that I have should have expected this, but to see it on a 'flat earth' reminds one of what is happening to a globe, or the earth itself. I expect others have more fun with other representations! Doug --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
[Fwd: Re: Terminator]
Douglas Bateman wrote: I have a site on my browser, www.mapmaker.com/shadowfacts/sunweb.asp that shows the terminator throughout the year. I Doug https://lists.uni-koeln.de/mailman/listinfo/sundial I have always loved the SunClock display. The changes through the seasons are indeed fascinating... I went to their site, and refreshed my memory of the various displays and products they offer. It's been a long time since I had a copy on my PC, and while I don't want it as a screensaver, I thought it would be nice to have the executable version again. G!! As I started to install it, my anti-spyware popped up and informed me LOPDOTCOM was trying to install itself. This is a particularly nasty commercial hijacker, that I doubt any of us wants on the desktop... http://anti-spyware-review.toptenreviews.com/spyware/lop.html Be warned, be aware, be safe! Dave --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Terminator
Another interesting site is: http://www.fourmilab.com/homeplanet/ If you haven't already come across it. Regards Andrew -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Douglas Bateman Sent: 19 March 2006 18:01 To: sundial@uni-koeln.de Subject: Terminator I have a site on my browser, www.mapmaker.com/shadowfacts/sunweb.asp that shows the terminator throughout the year. It is fascinating to see how rapidly the shape changes, and I was astonished to see this evening that it is nearly a straight line, as we approach the equinox. Of course, a little thought shows that I have should have expected this, but to see it on a 'flat earth' reminds one of what is happening to a globe, or the earth itself. I expect others have more fun with other representations! Doug --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Terminator
There is also a good depiction of the terminator on the under "Current Solar Data" on the NASS Web site. http://sundials.org/ Bob --- https://lists.uni-koeln.de/mailman/listinfo/sundial
