Re: Man Wants heliochronometer
Hi Kevin at all, If you want really high resolution from a small solar timekeeper, try a dipleidoscope! They can resolve down to a second or two. Regards, John Dr J Davis Flowton Dials From: Kevin Karney kar...@me.com These dials are latitude adjustable, correctable for longitude and summer time hours. They are meant for permanent installation so no do have levelling screws or compass. There is no my knowledge any heliochronometer that will tell the time better than 30 seconds accuracy, but I would love to be corrected on that! Best regards Kevin--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Man Wants heliochronometer
John, He wants a sundial that can tell the time to “THE SECOND”. He’ll be lucky! Does he realise that the difference per second will be 0.0042 of a degree. So you will be marking out the 24 hour time scale into 86,400 divisions. I have quite a few heliochronometers and the best one I have (that is still available) is a Gunning. Despite the claims, I think the Pilkington Gibbs heliochronometer is only accurate to 2 minutes, - it is only marked in 2 minute divisions and the cam is probably worn after 100 years! The PG Sol is marked to 1 minute and probably can (just) if you can find one. We think only about 50 were ever made, and I only know of 9 – do let me know if you have one. My Aten is an early one that doesn’t have the later vernier scale. I have a Silas Higgon (Bernhard type), but that’s only marked in 5 minute divisions. My Schmoyer Sunquest is a nice instrument, but is really a compromise heliochronometer. The Gunning IS accurate to a minute – you can’t really see the divisions smaller than that. That said, you really do have to know what you are doing to set it up: accurately orientated – flat and level in all directions and set to exactly the correct latitude. I found that the latitude scale as manufactured wasn’t accurate enough. Mike Shaw 53º 22' North 03º 02' West www.wiz.to/sundials--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re Man wants heliochronometer
Greetings, fellow dialists, Tom Kreyche wrote: With my Wild Heerbrugg T3000 Digital Theodolite equiped with a Roelofs Solar Prism I can achieve a few seconds accuracy for solar observations by taking a great deal of care with the sophisticated leveling system, assuming the base is stable, the temperature doesn't change, there is no wind and you don't touch the instrument. No doubt an experienced surveyor with astronomical observation experience can do better, or perhaps an experienced navigator with a good sextant. In fact any run-of-the-mill astro-navigator with a merely passable sextant could at least manage an accuracy of a minute of arc, or four seconds of time. Accuracy down to a tenth of a minute is quite possible. Would that be partly because sextant observations use the edge (limb) of the sun and not the less precise whole disc? Of course, the sea horizon, with a small correction, gives you a perfect level, too. For a really accurate dial could the east or west limb of the sun be projected and utilised? Frank 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Re Man wants heliochronometer
Dear Frank, As ever, you prompt several interesting trains of thought... In fact any run-of-the-mill astro-navigator with a merely passable sextant could at least manage an accuracy of a minute of arc... I have never used a sextant but I have heard this arc-minute figure so many times I am willing to believe it! ...or four seconds of time. Careful here! Most of the year the sun goes round in a small circle so an arc-minute change in position takes longer than four seconds. Also, I am not sure what angle you are measuring? You can't mean the solar altitude. That doesn't change anything like an arc-minute in 4s where I live! For a really accurate dial could the east or west limb of the sun be projected and utilised? Well you can project the whole solar disc using a continental camera obscura sundial and thereby see both east and west limbs of the sun. I have observed transit at the Basilica di S. Maria degli Angeli in Rome many times, sometimes with enthusiasic Italian diallists adding to the fun! Each diallist shouts Ora [Now] at what he perceives to be the critical moment and the chorus lasts two or three seconds, so that's an observational error for a start. The very first time I did this, I noted the time of the middle Ora on my radio-controlled watch and did the reductions. This includes allowing for the difference between UTC and UT1. It was pretty good, the error was about 3.5 seconds. Alas, I have done this many times since and noted errors of up to 10 seconds. There are too many things to go wrong... Mario Catamo says that you get a build-up of muck on one side of the hole which shifts the apparent centre. There would need to be a lot of muck to account for 10 seconds though! I believe the line isn't quite north-south but since I always go at much the same time of year the error should be consistent! That said, I think 10 seconds is pretty good. Frank Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
FW: Man Wants heliochronometer
This man wrote to me wanting to order a particular type of heliochronometer. I told him that I do not manufacture what he wants and that I would forward his resquest to The Sundial List. Perhaps one of you can sell him what he wants. See his description and photo below. Thx John From: ja.humb...@bluewin.ch [mailto:ja.humb...@bluewin.ch] Sent: Wednesday, May 22, 2013 4:11 PM To: jlcarmich...@comcast.net Subject: Accurate heliochronometer Hello, You do what I like! I am looking for a very accurate portable heliochronometer that can tell the time to the second in brass, no wood you know why! Shape more or less like picture, but with large Vernier scale, graduated latitude dial in half degrees around ca lat. 30 and 60, size 30-40 cm dial ring diameter, base plate with leveling screw for horizontal setting, compass in the base, precise and large analemma for equation of time, engraved hours and minutes on the ring if possible, motto and figurine on it. My position : lat. 46°31 minute N/long. 6°38 minute 50 sec. E. How about the price ? Best regards, Jacques Humbert Av. de Rumine 11 1005 Lausanne/CH atenII http://atensundials.com/images/at2big.jpg --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Man Wants heliochronometer
That is an Aten Sundial made by J. D. Gard http://atensundials.com Sadly Mr Gard has died and I do not know if the business has been continued by his wife. The website invites e-mail enquiries and no longer gives prices. These dials are latitude adjustable, correctable for longitude and summer time hours. They are meant for permanent installation so no do have levelling screws or compass. There is no my knowledge any heliochronometer that will tell the time better than 30 seconds accuracy, but I would love to be corrected on that! Best regards Kevin On 23 May 2013, at 16:26, John Carmichael jlcarmich...@comcast.net wrote: This man wrote to me wanting to order a particular type of heliochronometer. I told him that I do not manufacture what he wants and that I would forward his resquest to The Sundial List. Perhaps one of you can sell him what he wants. See his description and photo below. Thx John From: ja.humb...@bluewin.ch [mailto:ja.humb...@bluewin.ch] Sent: Wednesday, May 22, 2013 4:11 PM To: jlcarmich...@comcast.net Subject: Accurate heliochronometer Hello, You do what I like! I am looking for a very accurate portable heliochronometer that can tell the time to the second in brass, no wood you know why! Shape more or less like picture, but with large Vernier scale, graduated latitude dial in half degrees around ca lat. 30 and 60, size 30-40 cm dial ring diameter, base plate with leveling screw for horizontal setting, compass in the base, precise and large analemma for equation of time, engraved hours and minutes on the ring if possible, motto and figurine on it. My position : lat. 46°31 minute N/long. 6°38 minute 50 sec. E. How about the price ? Best regards, Jacques Humbert Av. de Rumine 11 1005 Lausanne/CH --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Man Wants heliochronometer
I wonder if there is an upper weight limit on portable sundials. Back in the old days of computers, there was a luggable category - maybe we should revive this as a sundial classification. Even with substantial material cutouts, a 30-40 cm brass dial would be a candidate. With m y Wild Heerbrugg T3000 Digital Theodolite equiped with a Roelofs Solar Prism I can achieve a few seconds accuracy for solar observations by taking a great deal of care with the sophisticated leveling system, assuming the base is stable, the temperature doesn't change, there is no wind and you don't touch the instrument . No doubt an experienced surveyor with astronomical osbservation experience can do better, or perhaps an experienced navigator with a good sextant. ...Tom Kreyche - Original Message - From: Kevin Karney kar...@me.com To: John Carmichael jlcarmich...@comcast.net Cc: Sundial Mailing List sundial@uni-koeln.de Sent: Thursday, May 23, 2013 9:33:46 AM Subject: Re: Man Wants heliochronometer That is an Aten Sundial made by J. D. Gard http://atensundials.com Sadly Mr Gard has died and I do not know if the business has been continued by his wife. The website invites e-mail enquiries and no longer gives prices. These dials are latitude adjustable, correctable for longitude and summer time hours. They are meant for permanent installation so no do have levelling screws or compass. There is no my knowledge any heliochronometer that will tell the time better than 30 seconds accuracy, but I would love to be corrected on that! Best regards Kevin On 23 May 2013, at 16:26, John Carmichael jlcarmich...@comcast.net wrote: This man wrote to me wanting to order a particular type of heliochronometer. I told him that I do not manufacture what he wants and that I would forward his resquest to The Sundial List. Perhaps one of you can sell him what he wants. See his description and photo below. Thx John From: ja.humb...@bluewin.ch [mailto:ja.humbert@ bluewin.ch ] Sent : Wednesday, May 22, 2013 4:11 PM To: jlcarmich...@comcast.net Subject: Accurate heliochronometer Hello, You do what I like! I am looking for a very accurate portable heliochronometer that can tell the time to the second in brass, no wood you know why! Shape more or less like picture, but with large Vernier scale, graduated latitude dial in half degrees around ca lat. 30 and 60, size 30-40 cm dial ring diameter, base plate with leveling screw for horizontal setting, compass in the base, precise and large analemma for equation of time, engraved hours and minutes on the ring if possible, motto and figurine on it. My position : lat. 46°31 minute N/long. 6°38 minute 50 sec. E. How about the price ? Best regards, Jacques Humbert Av. de Rumine 11 1005 Lausanne/CH atenII--- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Man Wants heliochronometer
Good Afternoon Always nice to know that David is still remembered for his beautiful instrument. I had high hopes of continuing the building of the Aten Heliochronometer after his death but as I am no machinist, I was unable to find anyone to make the dial at a reasonable cost. My sincere apologies for any confusion caused by the continuing existence of the website. As always in life, many other more pressing matters have had to be dealt with. This conversation serves as a reminder that I need to look in to what needs to be done. I continue to listen and learn through your conversations. Sincerely J Gard Sent from Windows Mail From: Tom Kreyche Sent: Thursday, May 23, 2013 10:07 AM To: sundial@uni-koeln.de I wonder if there is an upper weight limit on portable sundials. Back in the old days of computers, there was a luggable category - maybe we should revive this as a sundial classification. Even with substantial material cutouts, a 30-40 cm brass dial would be a candidate. With my Wild Heerbrugg T3000 Digital Theodolite equiped with a Roelofs Solar Prism I can achieve a few seconds accuracy for solar observations by taking a great deal of care with the sophisticated leveling system, assuming the base is stable, the temperature doesn't change, there is no wind and you don't touch the instrument. No doubt an experienced surveyor with astronomical osbservation experience can do better, or perhaps an experienced navigator with a good sextant. ...Tom Kreyche From: Kevin Karney kar...@me.com To: John Carmichael jlcarmich...@comcast.net Cc: Sundial Mailing List sundial@uni-koeln.de Sent: Thursday, May 23, 2013 9:33:46 AM Subject: Re: Man Wants heliochronometer That is an Aten Sundial made by J. D. Gard http://atensundials.com Sadly Mr Gard has died and I do not know if the business has been continued by his wife. The website invites e-mail enquiries and no longer gives prices. These dials are latitude adjustable, correctable for longitude and summer time hours. They are meant for permanent installation so no do have levelling screws or compass. There is no my knowledge any heliochronometer that will tell the time better than 30 seconds accuracy, but I would love to be corrected on that! Best regards Kevin On 23 May 2013, at 16:26, John Carmichael jlcarmich...@comcast.net wrote: This man wrote to me wanting to order a particular type of heliochronometer. I told him that I do not manufacture what he wants and that I would forward his resquest to The Sundial List. Perhaps one of you can sell him what he wants. See his description and photo below. Thx John From: ja.humb...@bluewin.ch [mailto:ja.humb...@bluewin.ch] Sent: Wednesday, May 22, 2013 4:11 PM To: jlcarmich...@comcast.net Subject: Accurate heliochronometer Hello, You do what I like! I am looking for a very accurate portable heliochronometer that can tell the time to the second in brass, no wood you know why! Shape more or less like picture, but with large Vernier scale, graduated latitude dial in half degrees around ca lat. 30 and 60, size 30-40 cm dial ring diameter, base plate with leveling screw for horizontal setting, compass in the base, precise and large analemma for equation of time, engraved hours and minutes on the ring if possible, motto and figurine on it. My position : lat. 46°31 minute N/long. 6°38 minute 50 sec. E. How about the price ? Best regards, Jacques Humbert Av. de Rumine 11 1005 Lausanne/CH atenII --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial--- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
