Re: Whats the time, where am I, whats on telly?
Hi all, A Brown wrote: I know John Davis gave a lively talk at a previous BSS meeting regarding the delineating of a dish as a sundial, I believe this may have involved covering the dish with a Mylar membrane. I hope I don't have to admit defeat and take out one of those awful microprocessor based finders! I did indeed - the dial (no longer in operation since the advent of digital satellites) can be seen on my website at www.flowton-dials.co.uk. Follow the links to Vertical Dials. If you (A Brown) want a reprint, let me know your address. I believe that there have been some US Patents on solar methods of aligning dishes in the past few years which would be worth seeking out. Good luck with an interesting project. Cheers, John --- Dr J R Davis Flowton Dials
Whats the time, where am I, whats on telly?
Fellow dial listSun worshipers come in all guises, my relative living in Australia follows the sun to the Northern Territories on an annual basis, migrating south again to Esperance (WA) for the summer season. Happy at forgoing fixed home comforts she pines for helpings of television soap opera to break the monotony of wild bush evensong (everything in life is relative).In exchange for lodgings and a 500 mile lift to a scratch in the sand on the Nullarbor Plain to witness Decembers Solar Eclipse I have foolishly promised to design and build a "Sun referenced satellite finder"The "instrument" is to enable them to easily point their dish at a range of satellites from virtually anywhere in Australia throughout the year by referencing the altitude and azimuth directions of the dish relative to the suns known location.Ideally the 1.2M dish would be marked up with lines showing particular satellites and intersecting lines showing the time of day the dish simply being moved to cast a bright spot at the required intersection or its interpolation.Since they would not necessarily know their exact location it may be that the process would have to be two stage with say a bubble built into the dishes altitude adjustment to determine latitude.This could also be used to set the polar mount axis to allow the dish to "sweep" the Clarke belt.The idea is to temporarily replace the prime focus satellite parabolic dish's LNB with an orifice plate capable of setting one of the required variables probably the date.I imagine this to be two coaxial disk on a common 40mm diameter axle which can be substituted for the LNB.One or perhaps both the disk could be rotated with the lower disk having an annelema slot and the upper a radial slot. This would give an aperture whilst of variable shape at a known position. The axle would be referenced to the clamp and hence the dish.The disk would be sized to cast a good shadow to give maximum contrast for the bright spot in the strong sunlight, whilst still allowing sufficient ambient light to read the designations.Has anyone built such a device, or think it feasible, I understand 1/2 a degree aiming accuracy should be sought.How would early Radio Telescope dishes like Jodrell Bank be first "calibrated"??I know John Davis gave a lively talk at a previous BSS meeting regarding the delineating of a dish as a sundial, I believe this may have involved covering the dish with a Mylar membrane.I hope I don't have to admit defeat and take out one of those awful microprocessor based finders!
Re: Whats the time, where am I, whats on telly?
A.Brown wrote: ... a Sun referenced satellite finder This is a page included on the NASS Link page. I think he is doing what you want to do. http://www.sundialsetup.com/ Bob Terwilliger NASS Webmaster Fellow dial list Sun worshipers come in all guises, my relative living in Australia follows the sun to the Northern Territories on an annual basis, migrating south again to Esperance (WA) for the summer season. Happy at forgoing fixed home comforts she pines for helpings of television soap opera to break the monotony of wild bush evensong (everything in life is relative). In exchange for lodgings and a 500 mile lift to a scratch in the sand on the Nullarbor Plain to witness Decembers Solar Eclipse I have foolishly promised to design and build a Sun referenced satellite finder The instrument is to enable them to easily point their dish at a range of satellites from virtually anywhere in Australia throughout the year by referencing the altitude and azimuth directions of the dish relative to the suns known location. Ideally the 1.2M dish would be marked up with lines showing particular satellites and intersecting lines showing the time of day the dish simply being moved to cast a bright spot at the required intersection or its interpolation. Since they would not necessarily know their exact location it may be that the process would have to be two stage with say a bubble built into the dishes altitude adjustment to determine latitude. This could also be used to set the polar mount axis to allow the dish to sweep the Clarke belt. The idea is to temporarily replace the prime focus satellite parabolic dish's LNB with an orifice plate capable of setting one of the required variables probably the date. I imagine this to be two coaxial disk on a common 40mm diameter axle which can be substituted for the LNB. One or perhaps both the disk could be rotated with the lower disk having an annelema slot and the upper a radial slot. This would give an aperture whilst of variable shape at a known position. The axle would be referenced to the clamp and hence the dish. The disk would be sized to cast a good shadow to give maximum contrast for the bright spot in the strong sunlight, whilst still allowing sufficient ambient light to read the designations. Has anyone built such a device, or think it feasible, I understand 1/2 a degree aiming accuracy should be sought. How would early Radio Telescope dishes like Jodrell Bank be first calibrated?? I know John Davis gave a lively talk at a previous BSS meeting regarding the delineating of a dish as a sundial, I believe this may have involved covering the dish with a Mylar membrane. I hope I don't have to admit defeat and take out one of those awful microprocessor based finders!
