[time-nuts] Result of Earth Quake speeds up earth?

[J. Forster]

> 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
>
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