[time-nuts] synchronization for telescopes

[Ilia Platone]

You got it, however: It only matters relative time. Start and Stop times 
will be known, and that is solved.
Someone has proposed using TV or other broadcasting carrier as reference 
clock: this can be another very cheap solution. There are many AM 
stations near the places we chosen, and these can be used.
A problem found was how to increase SNR: do you have a solution for 
this? If possible this method would be the best, since longer baselines 
could be made. The distance from the carrier source is not a problem 
since we'd use a GPS module at each telescope. Also the software part is 
not a problem too.
Good the relative timestamp also, as it saves HDD space.

Regards,
Ilia.

On 05/04/16 15:28, Chris Albertson wrote:
> One more comment.   It seems to me time-raging events is hard because you
> need many very good clocks that tracks absolute time.
>
> If you redefine the problem to be "determine the time difference between to
> events that occurred a couple nights ago it might be much easier.  This
> does not need to be done in real  time
>
> On Wed, May 4, 2016 at 8:25 AM, Chris Albertson <albertson.chris at gmail.com>
> wrote:
>
>> Maybe there is some simpler way to synchronize the telescopes.   Do they
>> even need to know the absolute time?  I think only relative time maters.
>>
>> For that all they need is some kind of a signal that all the telescope can
>> "see".   Could they use an FM or TV broadcast station?  They could sample
>> and record the signal at a very high sample rate (maybe 4X the career
>> frequency) and record their data at the same time.  each telescope would
>> need to know its distance to the broadcast antenna.
>>
>> The idea is to make the hardware cheaper and simpler and put all the
>> "work" on the post processing software developers.
>>
>> For this purpose, measuring the time difference of photons detected at
>> different locations, I don't think the broadcast career needs to be
>> exceptionally stable.  In post all you do to slide the recorded signal
>> until a best match is found.  So we do need a modulated carrier.  We also
>> have LOTS of data to use to compute the time alignment because you do it
>> later, we'd have billions of samples so it should be immune to noise
>>
>>
>>
>

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