[ARC5] NSS Cutler, ME
Roy Morgan
k1lky68 at gmail.com
Wed Nov 27 14:06:15 EST 2013
On Nov 27, 2013, at 11:57 AM, D C _Mac_ Macdonald <k2gkk at hotmail.com> wrote:
> Were time signals (ala WWV) once sent from a "Naval Observatory?" Was that once the location of WWV?
I’m not sure about radio transmissions from the Naval Observatory. It’s possible that time signals from the Observatory went by wire to the NBS/WWV site which was not far away at that time. As I have been writing this, Richard reports hearing time signals on NSS from Annapolis. Most likely there was a wire from the DC observatory headquarters over to Annapolis. And Mac reports hearing the voice time announcement. To See USNO time:
Main Navy Time link:
http://tycho.usno.navy.mil/ Click “Time” for the choices
Simple web page numerical display:
http://tycho.usno.navy.mil/simpletime.html
Animated GIF window:
http://tycho.usno.navy.mil/what1.html
The voice by telephone service:
Time Voice Announcer, Washington, DC: 202-762-1401 & 202-762-1069
Time Voice Announcer, Colorado Springs, CO: 719-567-6742
The Naval Observatory is in two places in DC. The headquarters is within sight of the Lincoln Memorial at the west end of the Mall. The mechanical clocks for Navy standard time were there, and the more modern physics-based ones may still be. The astronomical observatory was a few miles (maybe 4 miles) off to the North, still within the District of Columbia I think. The US Vice Presidents residence is there. There the now-ancient 24 (?) inch refractor telescope is still in operating condition, and the “Transit Telescope” is also. This latter was still in use in the late 80’s when I visited there. It is precisely fixed in rotation in east-west angle but moves easily in elevation. We watched the observer lie underneath it on a mechanics-like dolly and swing the telescope to watch a star transit the scope’s center line, and push a button at the right instant. That time mark, combined with much accurate calculation, and many more like it, establishes the sidereal time. As I understand it, sidereal time wanders a bit with respect to UTC (or NIST-A) time but is still used for some things. More info is at: http://tycho.usno.navy.mil/sidereal.html “… Astronomers use local sidereal time because it corresponds to the coordinate right ascension of a celestial body that is presently on the local meridian.” One of the very early transit telescopes was/is located in now-suburban Maryland in Rockville. The building is still there, but I don’t know if the instrument is.
The division of responsibility for time keeping is roughly: Military purposes, Naval Observatory. Civilian and international purposes: NIST/WWV. Naturally, the two organizations coordinate with each other.
During the early years, the WWV time broadcasts came from Greenbelt, MD, just to the NE of the District. That all moved to Boulder CO, (in the early 60’s I think). I remember hearing the time broadcasts from Greenbelt, and have visited the Boulder facility. At the time of the visit, there were three Master Clocks, made by HP I think, in operation I think there is a compare and vote system to eliminate one if it messes up. the voice that announces the time (and other things) is now solid state memory/playback, but it used to be a drum magnetic recorder that was played automatically.
The NIST Time and Frequency Division is part of the NIST Physics Laboratory. The research and development of newer time standards goes on at Boulder. When I was there they had become able to get the “Fountain Clock” to operate for some 20 minutes before it quit. No doubt by now the’ve made considerable progress. The “Fountain Clock” was calculated to develop an error of a second in some gad zillions of years. It’s quite possible that we won’t be here to notice the error.
Time is a most interesting topic.
Roy
Roy Morgan
RoyMorgan at alum.mit.edu
K1LKY Since 1958
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