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

[Bruce Griffiths]

jimlux wrote:
> On 3/15/11 9:36 PM, Hal Murray wrote:
>>
>>>> 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.
>>
>> What sort of accuracy can I get with:
>>    1) small/medium telescope in suburban back yard
>>    2) small/medium telescope out in the sticks
>>    3) big telescope in a good location
>>
>
> It's sort of time nutty...
>
> Couldn't you rig up a MLBI (medium, not very) setup between you and 
> someone else in your area..
>
> Could one detect pulses (or a signal) from some quasar (or "infinite 
> distance" stellar source) with a reasonable small antenna. 
Optical methods typically achieve positioning accuracies of around 10 
milliarcsec or so.
Radio methods are about 100x more accurate or around 100 micro arc sec.

To achieve the latter synchronisation between antennae has to be better 
than around 5us.
However to get fringes from the spectral region around the waterhole 
then relative synchronisation between receivers of a few tens of picosec 
is required.

Achieving such synchronisation even for an MLBI system would be 
something of a challenge without hydrogen masers or equivalent 
performance clocks at each antenna.

With care integration times of around half an hour or so are possible 
using a hydrogen maser at one antenna and an SRS FS725 rubidium standard 
another antenna.
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Using common view GPS carrier phase observables may be an option as long 
as the MLBI system isnt too large.

Bruce