[time-nuts] BYMLBI (Back Yard Medium LBI)

[Brooke Clarke]

Hi Bruce:

 From what I can learn about "seeing" the atmosphere instability is too 
great to allow making measurements optically in the 1 ms area.

It's a couple of acres.

Have Fun,

Brooke Clarke
http://www.PRC68.com


Bruce Griffiths wrote:
> Brooke Clarke wrote:
>> Hi:
>>
>> For a number of decades I've tried to figure out a way to measure the 
>> period of the Earth's rotation accurate to at least 1 ms.
>> For some thoughts (since I don't think it will work) on doing it 
>> optically see:
>> http://www.prc68.com/I/StellarTime.shtml
>>
>> Is it possible to do it using a radio method in my (large) back yard?
>>
>
> 1ms corresponds to an angle of 15 milliarcsec or 73 nrad for 0 
> declination objects.
>
> 15 milliarc sec positioning accuracy is just within the capability of 
> an 7" aperture transit circle or PZT equipped with a CCD camera.
> This accuracy was close to that achievable with a video camera 
> equipped transit circle in the late 1980's.
>
> A 2900 km diameter dish or equivalent has a resolution of about 73 
> nrad at 1420MHz.
> Position accuracy for a point source can be somewhat higher than the 
> resolution if the SNR is sufficiently high.
> However an antenna system of several hundred km in extent is likely to 
> be necessary.
>
> Just how large is your backyard?
>
> Bruce
>
>
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