....Yes, of course,..

Thanks, Peter.

   Jack

On 4/22/13, Peter <plpeter2006@yahoo.com> wrote:
> Gordon Williams <gwilliams <at> ncf.ca> writes:
>
>> I calculated 0.25 deg/min  (360 deg/day   /  1440 min/day =3D 0.25 deg/m=
in)
>> but maybe there are effects of latitude and date that I'm not
>> considering,
>> but I don't see that.
>>
>> Bob was not very specific with "not very bad" and "more severe"
>> assertions
>
> Yes, of course, my bad. Anyway 6 minute intervals make for a neat 8 bit
> clock which need not even be microcontroller driven. A little cmos divide=
r
> chain and a watch xtal and you're set. There was even a hack for ordinary
> mains operated led clocks, to mod them for amateur astronomy, the
> fractional
> correction needed to slow them down to astronomical clock mode was
> implemented in hardware using cycle stealing at the 50Hz mains clock leve=
l.
>
> Sidereal day is 86164.091712 seconds vs 86400 calendar day. Spreading tha=
t
> out evenly works out to 236 and a little seconds to steal, per day, or
> almost one for every 6 minute interval in a 6 minute period clock (there
> are
> 240 6 minute periods in a day), less 4 instances/day, running on 8 bits,
> with the fractional part treshed in using some phase accumulator over
> several days. of course this can be taken to much higher levels of
> refinement but there is no need at this point. There is nothing in this
> algorithm which can't run in a lowly 8 bit pic.
>
> -- Peter
>
>
>
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