1997 Greetings, Roderick and other List members, Roderick Wall wrote:
>Thought that you all may be interested in a window 95 software >program (AtomTime95) that you can use to set your PC clock on >time. So that when you use the NASS's Dialist program your clock >will be on time. >The URL address is: http://www.winternet.com/~adelsman/Software >Program file name is: atmtm12a.zip >AtomTime95 is a 32-bit Win95 Internet (Winsock) application which >will connect to the Atomic Clock time server in Boulder, CO and >fetch the current atomic clock time value. It compares this value >to your PC time and displays the difference. You then have the >option of updating your PC clock to match the atomic clock value. >There is also a command line option to have AtomTime >automatically set the clock and exit. 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. 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. 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.* 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!) End.
