[time-nuts] Sidereal timekeeping

Jean-Louis Oneto Jean-Louis.Oneto at obs-azur.fr
Tue May 17 12:50:02 UTC 2011


Hi again,
I forgot to mention this nice piece of software useful to check what you're 
doing:
http://www.gb.nrao.edu/~jbrandt/jLSTclock/
Jean-Louis
----- Original Message ----- 
From: "Jean-Louis Oneto" <Jean-Louis.Oneto at obs-azur.fr>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, May 17, 2011 12:27 PM
Subject: Re: [time-nuts] Sidereal timekeeping


> Hello list,
> I tried that a long time ago, but the trap I went into was that the 
> capacitance of the 'scope probe was pulling the frequency down, so I ended 
> with a crystal too high in frequency...
> I'm not sure that you can control the frequency without significantly 
> perturbing it. And waiting to check the rate between each tuning step 
> would take a long time...
> Regards,
> Jean-Louis
> ----- Original Message ----- 
> From: "Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> Sent: Tuesday, May 17, 2011 1:22 AM
> Subject: Re: [time-nuts] Sidereal timekeeping
>
>
>> Jim Lux wrote:
>>> On 5/16/11 2:58 PM, iovane at inwind.it wrote:
>>>> Neville,
>>>> at present I have not enough skill with micros to solve the problem.
>>>> I think I will try modifying a crystal. This would not be that 
>>>> difficult using
>>>> a lapping sheet or the like. And opening the can would be quite easy 
>>>> using hot
>>>> air.
>>>
>>> or a fine jeweler's saw or tubing cutter.
>>>
>>> As you pointed out, the crystals are cheap, so you can afford to ruin a 
>>> few while figuring out how to do it.
>>>
>>> (and then, remember us all, when you're a multi-billionaire having 
>>> cornered the market on sidereal rate crystals<grin>)
>>>
>>>
>> Since the 32 kHz crystal is likely to be a tuning fork form, one merely 
>> needs to shorten the tines to increase the frequency.
>> It may be feasible to do this without removing any of the electrode 
>> metallization.
>>
>> Bruce
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 





More information about the Time-nuts_lists.febo.com mailing list