Re: Sundial inside a room, but room is inside a canyon!
For more on mirror objectives, here is an article on using automobile hubcaps and parabolic L'eggs containers as reflectors. http://www.versacorp.com/vlink/jcart/allsky.htm Fisheye photographic lenses are another option, but expensive. Some early wide-angle camera lenses (for example, the Hill Sky Lens of 1926 for photographing clouds) used a glass hemisphere as the first lens element. This evolved into modern wide-angle and fisheye lenses. http://360vr.com/fisheye41/coastal-fisheyep.pdf I can envision using a wide-angle lens or mirror to form an image of the sky, a relay lens to form a second image of the sky in a room below, and a second reversed wide-angle lens in the room below to project an inverted image of the sun into the room. More simply, the second image could be projected onto a grid to show the time. Gordon Uber At 22:55 1/8/04, Edley McKnight wrote: Hi Tom, shadow watchers, A mirror objective might indeed work. Basically converting the large angular movement of the sun into a much narrower angle at the top and then re-expanding the angles at the bottom. This would be a curved mirror of course, or a set of small mirrors. Approximating it by a set of small mirrors would probably give insight to the proper curved mirror required. Essentially focusing all the sun's movement into a near column down the tube and then dispersing it again at the bottom. A double curving three dimensional mirror seems like it would be needed to keep from shadowing itself during part of the day. Thinking in terms of 'optical levers' might help. Is there an optical engineer of such caliber on board? -
Re: Sundial inside a room, but room is inside a canyon!
I have a question for those on this list with more experience (just about anyone!): What would happen if a mirror were used not to reflect the sun's image, but as the dial itself? As a kid, I had a mirror with an engraving of a deer on it in my room. I used to like to play with a flashlight at night by shining it on the mirror. The engraved image would become enlarged on the cieling, the opposite wall, etc. Could a mirrorsundial withattached gnomonbe placed on the owner's south facing wall or roof in such a way that the reflection would be on the neighbor's wall throughout the year? (Very similar to reflecting dials that reflect onto bedroom ceilings.) The image would change shape throughout the day and throughout the year I think, but would still be readable. Or would the mirror dial have to be humongous to do this? AF Edley McKnight [EMAIL PROTECTED] wrote: All:A simpler idea might be to just use a video camera with a fisheye lens. Maybe on top of a flagpole on top of the roof.Edley.Date sent: Thu, 08 Jan 2004 21:35:15 -0800From: Tom Egan <[EMAIL PROTECTED]>To: sundial@rrz.uni-koeln.deSubject: Re: Sundial inside a room, but room is inside a canyon!Send reply to: sundial@rrz.uni-koeln.de All: Yet another possibility, a back-to-basics one: When I told my neighbor that his north wall is now known around the globe, thanks to the Dialist Board, he announced that demolishing his second story was now an option. With a hearty chuckle, he said, "For the right price." I thanked him for his concession, but shall continue to pursue lower-cost options to bring the sun into my first-story room. S! eriously, I appreciate the thoughtfulness of all your comments. I've learned a lot and enjoyed myself at the same time! Tom Egan tony moss wrote: Fellow Shadow Watchers, Why not have an electro-mechanical 'sun tracker' on the roof with an electro-mechanical 'repeater' in the room which could be placed on a wall for easy reading. This could take the shape of a 'hour hand' on a 'dial' with a 1:24 gearing to drive a concentric hand to show minutes. A simple ambient sunshine detector would switch off the tracker when the sun was obscured with a warning light on the dial to indicate this. When the sun re-appearerd the tracker could then switch to 'search' mode to relocate it thus avoiding frantic spuirious indications below. Digital clocks are cheaper of course but making it work would ! be a lot of fun ;-) Tony Moss. - -- Do you Yahoo!? Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
Re: Sundial inside a room, but room is inside a canyon!
Good, Mike. A fine example of thinking outside the house. -Bill In a message dated 1/9/2004 4:18:28 AM Eastern Standard Time, [EMAIL PROTECTED] writes: Tom, Instead of demolishing your neighbour's 2nd floor, consider adding a third floor to your own house. This could have additional advantages. Mike Shaw -
Re: Sundial inside a room, but room is inside a canyon!
But one that couls lead to escalating the situation... Dave Good, Mike. A fine example of thinking outside the house. -Bill In a message dated 1/9/2004 4:18:28 AM Eastern Standard Time, [EMAIL PROTECTED] writes: Tom, Instead of demolishing your neighbour's 2nd floor, consider adding a third floor to your own house. This could have additional advantages. Mike Shaw - -
Re: Sundial inside a room, but room is inside a canyon!
Hi Tom, shadow watchers, A mirror objective might indeed work. Basically converting the large angular movement of the sun into a much narrower angle at the top and then re-expanding the angles at the bottom. This would be a curved mirror of course, or a set of small mirrors. Approximating it by a set of small mirrors would probably give insight to the proper curved mirror required. Essentially focusing all the sun's movement into a near column down the tube and then dispersing it again at the bottom. A double curving three dimensional mirror seems like it would be needed to keep from shadowing itself during part of the day. Thinking in terms of 'optical levers' might help. Is there an optical engineer of such caliber on board? On the color sampling, tubes rather than slits would be needed to sample both the hour-angle and declination ( or azimuth and elevation ) Hope this helps! Edley. Yet another possibility, a back-to-basics one: When I told my neighbor that his north wall is now known around the globe, thanks to the Dialist Board, he announced that demolishing his second story was now an option. With a hearty chuckle, he said, For the right price. I thanked him for his concession, but shall continue to pursue lower-cost options to bring the sun into my first-story room. Seriously, I appreciate the thoughtfulness of all your comments. I've learned a lot and enjoyed myself at the same time! Tom Egan tony moss wrote: Fellow Shadow Watchers, Why not have an electro-mechanical 'sun tracker' on the roof with an electro-mechanical 'repeater' in the room which could be placed on a wall for easy reading. This could take the shape of a 'hour hand' on a 'dial' with a 1:24 gearing to drive a concentric hand to show minutes. A simple ambient sunshine detector would switch off the tracker when the sun was obscured with a warning light on the dial to indicate this. When the sun re-appearerd the tracker could then switch to 'search' mode to relocate it thus avoiding frantic spuirious indications below. Digital clocks are cheaper of course but making it work would be a lot of fun ;-) Tony Moss. - - -
Re: Sundial inside a room, but room is inside a canyon!
Instead of demolishing your neighbour's 2nd floor, consider adding a third floor to your own house. This could have additional advantages. Mike Shaw 53.37 North 03.02 West http://www.wiz.to/sundialswww.wiz.to/sundials Good one, Mike! Following another of your ideas, instead of a fixed dial and a moving sun, Tom might consider a fixed indoor light illuminating a slowly rotating dial. Mac P.S. Also, I think I remember seeing a program which puts a simulated sundial on your computer screen, using the location and orientation of the computer and the time from its system clock. Can anyone recall the name of such a program? -
Re: Sundial inside a room, but room is inside a canyon!
Tom, Instead of demolishing your neighbour's 2nd floor, consider adding a third floor to your own house. Thiscould have additional advantages. Mike Shaw 53.37 North03.02 West www.wiz.to/sundials
Re: Sundial inside a room, but room is inside a canyon!
Yet another possibility, a back-to-basics one: When I told my neighbor that his north wall is now known around the globe, thanks to the Dialist Board, he announced that demolishing his second story was now an option. With a hearty chuckle, he said, For the right price. I thanked him for his concession, but shall continue to pursue lower-cost options to bring the sun into my first-story room. Seriously, I appreciate the thoughtfulness of all your comments. I've learned a lot and enjoyed myself at the same time! Tom Egan tony moss wrote: Fellow Shadow Watchers, Why not have an electro-mechanical 'sun tracker' on the roof with an electro-mechanical 'repeater' in the room which could be placed on a wall for easy reading. This could take the shape of a 'hour hand' on a 'dial' with a 1:24 gearing to drive a concentric hand to show minutes. A simple ambient sunshine detector would switch off the tracker when the sun was obscured with a warning light on the dial to indicate this. When the sun re-appearerd the tracker could then switch to 'search' mode to relocate it thus avoiding frantic spuirious indications below. Digital clocks are cheaper of course but making it work would be a lot of fun ;-) Tony Moss. - -
Re: Sundial inside a room, but room is inside a canyon!
Fellow Shadow Watchers, Why not have an electro-mechanical 'sun tracker' on the roof with an electro-mechanical 'repeater' in the room which could be placed on a wall for easy reading. This could take the shape of a 'hour hand' on a 'dial' with a 1:24 gearing to drive a concentric hand to show minutes. A simple ambient sunshine detector would switch off the tracker when the sun was obscured with a warning light on the dial to indicate this. When the sun re-appearerd the tracker could then switch to 'search' mode to relocate it thus avoiding frantic spuirious indications below. Digital clocks are cheaper of course but making it work would be a lot of fun ;-) Tony Moss. -
Re: Sundial inside a room, but room is inside a canyon!
This led me to consider an offshoot of the skylight concept. Some of my neighbors have installed a "solar tube" which provides a skylight effect in a remote room by reflecting the sunlight down the shiny inner wall of a tube roughly one foot in diameter. The light emerges at the lower end of the tube. It emerges quite brightly, I might add. I originally hoped I could install such a tube, mount a sundial beneath the lower end and watch the time go by from the comfort of my family room. I don't think it's that simple, though. If the sun's instant by instant azimuth and elevation in the sky is "information," then that information must get completely garbled up and lost as the rays bounce their way down the pipe. You don't want a tube, but a box. If you set up a rectangular prism so that sunlight can get in the top and out the bottom in your living room, then the rays will exit at the same angle they entered. (The prism need not be vertical.) Well, actually only those rays that make an even number of reflections from each pair of parallel faces will emerge in the same direction they entered. If you want to eliminate the rays emerging in the three wrong directions, you will have to get clever. The other solution is to use imaging optics. Put a small mirror near the "canyon rim" and another in your living room or just outside the window. Focus the image of the first mirror onto the second one with a lens or concave mirror. The first problem is that the f-number of the mirror must be small to catch the sun over most the day, so it will have to be very close to the first mirror. The angular deviations of the rays at the second mirror will then be very small, but you can either design the readout appropriately or re-expand them with another lens or spherical mirror. You must also be careful to keep the small mirrors near the axis of the focussing element to avoid distortion. Fiber optics is certainly a way of preserving and transmitting the information for use at a remote location. But is there another way? Could the incoming light be polarized -- maybe in four sectors for N, E, W, S information -- to preserve the azimuth and elevation in its travels down the tube? Could some esoteric principles of radar be invoked to usefully tap into the information at various points along the tube, or at the end? (All I know about radar is that the microwave energy bounces around in hollow waveguides and the practitioners of the black art are able to somehow work magic with it.) Fiber optics are the equivalent of radar waveguides for light. Both are usually, though not necessarily, operated in single-mode, in which case, as you say, the information they are capable of transmitting is limited. My first suggestion of a reflecting box can be considered a multi-mode waveguide that is capable of preserving some angular information. Have fun, Art Carlson
Re: Sundial inside a room, but room is inside a canyon!
Hi Tom, Being an old Microwave engineer I don't believe that the information could be recaptured after bouncing around the tube, but an alternative optical method might work. A very wide angle lens at the top, looking roughly south configured to have a very long focal length on the back side, reflected down the tube and back out into a circular dispersing reflecting mirror to your more or less conventional sundial. There would probably be serious distortions in the signal, but the information would be there, possibly corrected with an aspheric lens within the system. Being an old Navy man as well, it seems that there were panoramic periscopes that might lend some clues. A raytracing or lens design program might be able to help. Of course there are any number of ways that the information could be sampled and sent in a discrete fashion. A set of tubes or slits at the top with different colored filters at their inner end could reflect a color down the pipe to indicate the time for instance. I hope this starts a rush of thoughts that will help find an answer. Edley McKnight From: Tom Egan [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Subject:Re: Sundial inside a room, but room is inside a canyon! Hi John, Interestingly, the notion of a skylight is what got me going on this perhaps quixotic quest. My house is two stories high. The room where I want the indoor sundial is on the first floor, so I'd have to demolish most of the room above. My neighbor wouldn't mind this particular demolition, of course, but the grandkids who were used to sleeping there would, no doubt, protest. This led me to consider an offshoot of the skylight concept. Some of my neighbors have installed a solar tube which provides a skylight effect in a remote room by reflecting the sunlight down the shiny inner wall of a tube roughly one foot in diameter. The light emerges at the lower end of the tube. It emerges quite brightly, I might add. I originally hoped I could install such a tube, mount a sundial beneath the lower end and watch the time go by from the comfort of my family room. I don't think it's that simple, though. If the sun's instant by instant azimuth and elevation in the sky is information, then that information must get completely garbled up and lost as the rays bounce their way down the pipe. Fiber optics is certainly a way of preserving and transmitting the information for use at a remote location. But is there another way? * Could the incoming light be polarized -- maybe in four sectors for N, E, W, S information -- to preserve the azimuth and elevation in its travels down the tube? * Could some esoteric principles of radar be invoked to usefully tap into the information at various points along the tube, or at the end? (All I know about radar is that the microwave energy bounces around in hollow waveguides and the practitioners of the black art are able to somehow work magic with it.) Tom John Carmichael wrote: Hi Tom: Is a skylight hole in your roof possible? This would eliminate most of your problems with mirrors. You don't need a flat roof. A skylight hole could be used for any of the interior dials I mentioned. John L. Carmichael Jr. 925 E. Foothills Dr. Tucson Arizona, USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - -
Re: Sundial inside a room, but room is inside a canyon!
I would suggest: create the sundial on your neighbors waal only for the hours your south facing wall is not sun lit. For the other hours you can make your sundial on your own wall. Thibaud At 22:03 04-01-2004, you wrote: I sketched out a vertical dial, figuring a mirror as the nodus on a pin gnomon perpendicular to the dial face, using Fer J. de Vries' ZW2000 software. I used my northern California coordinates. It's a *little* large, for a suburban home. A mirror 10 feet from the plane of the wall seems to require a dial face on the order of 86 feet wide by 50 feet tall! If the small attachment comes through, it should explain it... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Dave, Tom, It is not that difficult, mirror the neighbors wall in relation to the mirror, so it will be some imaginary wall in Tom's house. The mirror is the tip of the gnomon, or a little window whatever you like. The south facing dial on the mirrored neighbors wall has to be mirrored back: left and right should switched like top and bottom. And that is simply done by rotating the whole design around a horizontal perpendicular axis. Thibaud At 18:21 04-01-2004, you wrote: I love it! If Tom can sell his neighbor on the esthetic upgrade to his house, it's a great solution. How does the geometry work out? Would the mirror need to be *very* high, say, over 2 stories itself? Closer, or farther than Tom's South wall? I guess the design trick would be to calculate a South-facing dial with a nodus 10 feet away from the face, and adjust the nodus hieght to fit... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Tom, There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W- - - Thibaud Taudin-Chabot 52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m home email: [EMAIL PROTECTED] - - Thibaud Taudin-Chabot 52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m home email: [EMAIL PROTECTED] -
Re: Sundial inside a room, but room is inside a canyon!
regularly find on this dialist board. This is a great example of it. Thank you, Thibaud! If this ever comes to pass, I'll report on it to the board. Tom Thibaud Taudin-Chabot wrote: Tom, There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W -
Re: Sundial inside a room, but room is inside a canyon!
Hi John, Interestingly, the notion of a skylight is what got me going on this perhaps quixotic quest.� My house is two stories high.� The room where I want the indoor sundial is on the first floor, so I'd have to demolish most of the room above.� My neighbor wouldn't mind this particular demolition, of course, but the grandkids who were used to sleeping there would, no doubt, protest.� This led me to consider an offshoot of the skylight concept.� Some of my neighbors have installed a "solar tube" which provides a skylight effect in a remote room by reflecting the sunlight down the shiny inner wall of a tube roughly one foot in diameter.� The light emerges at the lower end of the tube.� It emerges quite brightly, I might add. I originally hoped I could install such a tube, mount a sundial beneath the lower end and watch the time go by from the comfort of my family room.� I don't think it's that simple, though.� If the sun's instant by instant azimuth and elevation in the sky is "information," then that information must get completely garbled up and lost as the rays bounce their way down the pipe. Fiber optics is certainly a way of preserving and transmitting the information for use at a remote location.� But is there another way?� Could the incoming light be polarized -- maybe in four sectors for N, E, W, S information -- to preserve the azimuth and elevation in its travels down the tube? Could some esoteric principles of radar be invoked to usefully tap into the information at various points along the tube, or at the end?� (All I know about radar is that the microwave energy bounces around in hollow waveguides and the practitioners of the black art are able to somehow work magic with it.) Tom John Carmichael wrote: Hi Tom: � Is a skylight hole in your roof possible?� This would eliminate most of your problems with mirrors.� You don't need a flat roof.� A skylight hole could be used for any of the interior dials I mentioned. � � John L. Carmichael Jr. 925 E. Foothills Dr. Tucson Arizona, USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Sundial Sculptures Website: http://www.sundialsculptures.com Stained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass -
Re: Sundial inside a room, but room is inside a canyon!
Hi Edley and all, The plot thickens! What if, instead of a lens, a reflector is used? Suppose I borrow the so-called Victorian gazing ball from my garden (a large metal ball with a mirror finish, about 30 cm diameter) and mount it at the edge of my roof. If I lie underneath it and observe the path of the bright spot throughout the day, I'll see the path as a curve starting near the easternmost extreme of the ball in the morning and ending near the westernmost extreme. If I persist in this supine research through all the seasons, I'll have seen every possible position of the sun apparently condensed onto this 30 cm ball (assuming I'm far enough north (or south) so that the ball never comes between the sun and my eye). Now, suppose I mount a plane mirror beneath the ball, just outside a window. If I tilt it 45 degrees (or should I have said 0.785 radians?), I can reflect the condensed sun path horizontally through the window and into my room. (BTW, I hope the metric folks out there appreciate all the effort I'm putting into trying to be international by converting from god-given units of feet and inches!) At this point, I think the position information (azimuth, elevation) will have been preserved, although any asphericity of the ball will introduce noise. Once the condensed sun path is in the room, I can fool around with it. I can use a 45 deg. plane mirror to deflect it down onto a pedestal-mounted sundial face. Or I could bounce it off another Victorian gazing ball, thereby expanding the condensed information into something that could (maybe) trace out the sun's position on a wall or ceiling. Questions abound: Is there any constraint on the size of the outside 45 deg. mirror? Should the mirror be tiny -- say 5 mm across -- in order to create a narrow beam? Or must it be larger so as to not miss any of the path information? Would an inside ball actually expand the condensed path onto a wall or ceiling? Cheers, Tom Edley McKnight wrote: Hi Tom, Being an old Microwave engineer I don't believe that the information could be recaptured after bouncing around the tube, but an alternative optical method might work. A very wide angle lens at the top, looking roughly south configured to have a very long focal length on the back side, reflected down the tube and back out into a circular dispersing reflecting mirror to your more or less conventional sundial. There would probably be serious distortions in the signal, but the information would be there, possibly corrected with an aspheric lens within the system. Being an old Navy man as well, it seems that there were panoramic periscopes that might lend some clues. A raytracing or lens design program might be able to help. Of course there are any number of ways that the information could be sampled and sent in a discrete fashion. A set of tubes or slits at the top with different colored filters at their inner end could reflect a color down the pipe to indicate the time for instance. I hope this starts a rush of thoughts that will help find an answer. Edley McKnight -
Re: Sundial inside a room, but room is inside a canyon!
I love it! If Tom can sell his neighbor on the esthetic upgrade to his house, it's a great solution. How does the geometry work out? Would the mirror need to be *very* high, say, over 2 stories itself? Closer, or farther than Tom's South wall? I guess the design trick would be to calculate a South-facing dial with a nodus 10 feet away from the face, and adjust the nodus hieght to fit... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Tom, There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W- -
Re: Sundial inside a room, but room is inside a canyon!
I sketched out a vertical dial, figuring a mirror as the nodus on a pin gnomon perpendicular to the dial face, using Fer J. de Vries' ZW2000 software. I used my northern California coordinates. It's a *little* large, for a suburban home. A mirror 10 feet from the plane of the wall seems to require a dial face on the order of 86 feet wide by 50 feet tall! If the small attachment comes through, it should explain it... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Dave, Tom, It is not that difficult, mirror the neighbors wall in relation to the mirror, so it will be some imaginary wall in Tom's house. The mirror is the tip of the gnomon, or a little window whatever you like. The south facing dial on the mirrored neighbors wall has to be mirrored back: left and right should switched like top and bottom. And that is simply done by rotating the whole design around a horizontal perpendicular axis. Thibaud At 18:21 04-01-2004, you wrote: I love it! If Tom can sell his neighbor on the esthetic upgrade to his house, it's a great solution. How does the geometry work out? Would the mirror need to be *very* high, say, over 2 stories itself? Closer, or farther than Tom's South wall? I guess the design trick would be to calculate a South-facing dial with a nodus 10 feet away from the face, and adjust the nodus hieght to fit... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Tom, There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W- - - Thibaud Taudin-Chabot 52 18' 19.85 North, 04 51' 09.45 East, alt. -4.50 m home email: [EMAIL PROTECTED] - Content-Type: IMAGE/GIF; name=MirrorDial.GIF Content-ID: [EMAIL PROTECTED] Content-Description: Content-Disposition: attachment; filename=MirrorDial.GIF Attachment converted: Macintosh HD:MirrorDial.GIF (GIFf/JVWR) (000B088B)
Re: Sundial inside a room, but room is inside a canyon!
Hi Tom: Is a skylight hole in your roof possible? This would eliminate most of your problems with mirrors. You don't need a flat roof. A skylight hole could be used for any of the interior dials I mentioned. John L. Carmichael Jr.925 E. Foothills Dr.Tucson Arizona, USATel: 520-696-1709Email: [EMAIL PROTECTED]Sundial Sculptures Website: http://www.sundialsculptures.comStained Glass Sundials Website: http://advanceassociates.com/Sundials/Stained_Glass - Original Message - From: Tom Egan To: sundial@rrz.uni-koeln.de Sent: Saturday, January 03, 2004 11:36 PM Subject: Sundial inside a room, but room is inside a canyon! I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says.I thought of using mirrors to relay the sun's rays down the canyon between our houses, much as a periscope would. This could be an extension of John Carmichael's reflection sundial (#4 in his reply to Ronit) Several problems with that, since the horizon-to -horizon and season-to-season arc of the sun would require either A small mirror on top and a huge mirror at the bottom end, plus a huge aperture, or A large set of individually aligned small mirrors on top that are focused on a small mirror at bottom. Then I thought of a bundle of optical fibers to carry the sun position information down to a dial or display inside the room. This might be considered an extension of John's #3 projection dial. A little better, but still requiring precise aligning of hundreds of individual fibers at the top end. Plus the disadvantage of losing some resolution and brightness because of quantizing the information (in discrete fibers) and then transmitting it through glass instead of air.Finally, I remembered Mike Shaw's clever implementation of an Indoor Dial he reported on October 29 (or thereabouts), 2000. He used a 150 mm diameter, plastic sewer pipe to hold the fibers in an equatorial semicircle. While he could have installed enough fibers to give 5-minute resolution, he chose to start with just 15-minute resolution. The display ends of the fibers were arranged around the periphery of a clock face. He reported that plenty of light gets down to the display.This isn't quite what I'm looking for, though, as I'd like the equivalent of a garden sundial in my room whose gnomon casts a shadow. I think I can now properly formulate my question: Is there a way to get the sun's rays down to my room so I can have them illuminate an ordinary sundial? (Without demolishing my neighbor's house or spending a ton of money?)Tom Egan33.642 N, 117.943 W-
Re: Sundial inside a room, but room is inside a canyon!
There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W- - Thibaud Taudin-Chabot 52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m home email: [EMAIL PROTECTED] -
Re: Sundial inside a room, but room is inside a canyon!
It is not that difficult, mirror the neighbors wall in relation to the mirror, so it will be some imaginary wall in Tom's house. The mirror is the tip of the gnomon, or a little window whatever you like. The south facing dial on the mirrored neighbors wall has to be mirrored back: left and right should switched like top and bottom. And that is simply done by rotating the whole design around a horizontal perpendicular axis. Thibaud At 18:21 04-01-2004, you wrote: I love it! If Tom can sell his neighbor on the esthetic upgrade to his house, it's a great solution. How does the geometry work out? Would the mirror need to be *very* high, say, over 2 stories itself? Closer, or farther than Tom's South wall? I guess the design trick would be to calculate a South-facing dial with a nodus 10 feet away from the face, and adjust the nodus hieght to fit... Dave 37.277N 121.966W On Sun, 4 Jan 2004, Thibaud Taudin-Chabot wrote: Tom, There is an other solution: Put a miiror high on your south facing wall which will reflect the sun on your neighboors North wall. Design a sundial for that North Facing wall of your neighboor. He will never look at it but you see it all the time. Thibaud At 07:36 04-01-2004, you wrote: I have a nice, south-facing room. The trouble is, my neighbor's two-story house is about 10 feet away, due south. Consequently, if I cut an aperture in my wall, the sun would find it only mid-summer. The rest of the time, my neighbor's roof would block the sun. Demolishing his second story is not an option, he says. Tom Egan 33.642 N, 117.943 W- - - Thibaud Taudin-Chabot 52° 18' 19.85 North, 04° 51' 09.45 East, alt. -4.50 m home email: [EMAIL PROTECTED] -
