> Does anyone here know the current state of the art for timing the > Earth's rotation? I know the outline, An instrument on a transit > telescope notes the time when a star passes overhead. You take many > of these observations and you can determine the period
Radio VLBI of Quasars comes to mind. > What is the instrument of choice? Several radio telescopes. > Is it still a transit telescope or > do that track a star's motion over a longer span of time? I'd guess > that getting a good rotational period would required tracking many > stars over months and years. Lower accuracy than VLBI. > What about effects like parallax due to the Earth's orbit around the > sun,? Do they only use very distant stars? Or do they use radio > telescopes now. > > If I were doing this in my backyard on a budget I'd mount a small > telescope nearly straight up so that a bright star would pass through > the field on several nights. I'd measure the light of the star > through a slit and time the peak of the light each night. I bet I > could get to about a microsecond. I'm wondering what professionals > are doing in this field. I have references for VLBI, if you want. You probably cannot do optical accurately enough because of "seeing" effects, at least. -John ============== > > > -- > ===== > Chris Albertson > Redondo Beach, California > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
