Hi all, On Jan 4, 2:55pm, Wm. S. Maddux wrote:
> Subject: Internet program to set your clock for the Dialist program. > 1997 Greetings, Roderick and other List members, > > Thank you for the information, Roderick, but perhaps a word of > caution on the List about using PCs as clocks is in order: > > Dial-related timings (of sun shadows) rarely, if ever, result > in discrimination to better than several seconds uncertainty. > However, the display on an ordinary PC is liable to be wrong > by larger errors than that, due to the limitations of the > internal clocks used in PCs, unless special measures are > taken. (See an article in the Feb. 1996 SKY & TELESCOPE, > pp 81 to 83, that discusses PCs as timekeepers, and suggests > some dodges to improve their performance.) In practice, it > doesn't seem important to me for the ways I use my computer > re dials. > Thanks Bill for the above information in SKY & TELESCOPE on how to improve the PC's clock. I had no other way of doing this and I found the AtomTime95 program to do the job. > For me, one of the values of dialing as a hobby is its tie to > consideration of the real world in real time, and its bringing > awareness of astronomical connections into direct conscious > context for my everyday life. I spend lots of time using the > computer as a mathematical tool, and as a means of communication, > but it is the time spent making and playing with shadow-catching > toys in real sunshine that brings me greatest satisfaction. I agree it is fun designing, making and setting up dials I also find that this part also brings me the greatest satisfaction. I also use the computer as a tool to help me design sundials. > > When engaged in direct outdoor sundialing activities, I rely upon > an inexpensive "quartz" digital watch, less cumbersome than any > laptop would be, for timing sun positions by shadow observation. > The watch (Casio) that I use cost about 12 US-dollars. I have > checked it routinely -- once a month, over the last three years, > using WWV, Fort Collins, shortwave signals. The watch has had > a very predictable rate (gains between 9 and 10 second in 30 days) > with only a slight indication of temperature sensitivity within > my non-air-conditioned workshop's annual range of approximately > 16 to 32 degree C.* > I also use a quartz watch as the computer is too large to take outside. I notice that you use WWV Fort Collins shortwave signals to check the timing of your quartz watch. You are lucky in that in Australia we can't always receive WWV on shortwave (then it is only sometimes at night). But now, all I have to do is to connect onto the INTERNET set the PC's clock (with AtomTime95) then check my quartz watch with the Date/Time window that is in the windows 95 Control Panel (Under settings). > If I'm being fussy, I "ad hoc" compare the watch with WWV > within an hour or so of making observations and apply any > differential found to my recorded times. Frankly, this is > overkill, because as a variable, Standard Time determination > has never been a significant source of error for any of the > dial-related measurements I have ever made, even without such > extra precautions. > > Bill Maddux > > *(For comparison, my own PC accumulates time error at a rate > of well over a minute per day! Try checking your own!) I have never checked my PC's clock. A rate of over a minute per day is a lot I will check it tomorrow. > >-- End of excerpt from Wm. S. Maddux Thanks Bill for the above information happy sundialing. Roderick Wall. -- _______________________________ Roderick Wall E-mail: [EMAIL PROTECTED] Melbourne Australia. ________________________________
