sidereal clock for sale

On Tuesday, April 30, 2002 at 10:43:16 PM UTC, Bryan Mumford wrote:
Mumford Micro Systems is making an analog quartz sidereal clock for sale.
It was created at the request of staff at Mt. Wilson and may be of
interest to amateurs who want to keep an eye on local sidereal time. Local
sidereal time is the Right Ascension of objects currently at the zenith.

See:
http://www.bmumford.com/clocks/sidereal/index.html

--
Bryan Mumford
www.bmumford.com

Convert An Existing Clock By Replacing the 32768 crystal with a 32858 crystal then calibrate it against WWV 1000 HZ tone using a variable condenser of the right value. Sidereal time is simply one more day within the same civil year period. so like 32768 * 366.25/365.25 should be the new frequency.

On Thursday, April 13, 2017 at 5:52:28 PM UTC-6, wrote:

Convert An Existing Clock By Replacing the 32768 crystal with a 32858 crystal

Um, isn't the problem that they don't _make_ 32858 crystals that you can just
easily run out and buy?

John Savard

On Thursday, April 13, 2017 at 6:23:58 PM UTC-6, Quadibloc wrote:
On Thursday, April 13, 2017 at 5:52:28 PM UTC-6, wrote:

Convert An Existing Clock By Replacing the 32768 crystal with a 32858 crystal

Um, isn't the problem that they don't _make_ 32858 crystals that you can just
easily run out and buy?

I found this thread:

https://forum.cosmoquest.org/archive...p/t-54749.html

Somebody ordered 500 custom quartz crystals at 32.8577 kHz, which is more
accurately the needed frequency. Maybe he still has some.

John Savard

On Thu, 13 Apr 2017 17:29:29 -0700 (PDT), Quadibloc
wrote:

On Thursday, April 13, 2017 at 6:23:58 PM UTC-6, Quadibloc wrote:
On Thursday, April 13, 2017 at 5:52:28 PM UTC-6, wrote:

Convert An Existing Clock By Replacing the 32768 crystal with a 32858 crystal

Um, isn't the problem that they don't _make_ 32858 crystals that you can just
easily run out and buy?

I found this thread:

https://forum.cosmoquest.org/archive...p/t-54749.html

Somebody ordered 500 custom quartz crystals at 32.8577 kHz, which is more
accurately the needed frequency. Maybe he still has some.

I'd just go with one of the zillion available sidereal clock apps for
a smartphone.

On Friday, 14 April 2017 06:14:26 UTC+2, Chris L Peterson wrote:

I'd just go with one of the zillion available sidereal clock apps for
a smartphone.

But what will happen when 'Baby' Kim throws an EMP 'tantrum' over the US?

I should start whittling a wooden pendulum now. Just in case.

You can tie on a bag of last week's obsolete iPhonies as a bob. ;-)

On Thursday, April 13, 2017 at 10:14:26 PM UTC-6, Chris L Peterson wrote:

I'd just go with one of the zillion available sidereal clock apps for
a smartphone.

I was thinking it might be possible to use a computer to convert a time signal to
the sidereal rate...

John Savard

On 14/04/2017 01:23, Quadibloc wrote:
On Thursday, April 13, 2017 at 5:52:28 PM UTC-6, wrote:

Convert An Existing Clock By Replacing the 32768 crystal with a 32858 crystal

Um, isn't the problem that they don't _make_ 32858 crystals that you can just
easily run out and buy?

Indeed. Minimum order is about 1000 parts and a batch setup cost on top.
Someone did it a long while ago they might still have some left.

The way I did it was make a normal clock using a LCD display and 16F877
and provide a switch to allow solar or sidereal timekeeping with an
ability to tweak the second and digitally correct to 1ppm daily.

I intended to add temperature compensation but it worked well enough at
that point so I gave up.

Converting master pendulum clocks originally intended for clocking in
systems to an observatory sidereal clock is quite doable by shortening
the pendulum within the limits allowed by the adjuster.

Today there are any number of smartphone apps that will do sidereal time
and some predictions of satellite passes and Iridium flares too.

--
Regards,
Martin Brown

wrote:
On Tuesday, April 30, 2002 at 10:43:16 PM UTC, Bryan Mumford wrote:
Mumford Micro Systems is making an analog quartz sidereal clock for sale.
It was created at the request of staff at Mt. Wilson and may be of
interest to amateurs who want to keep an eye on local sidereal time. Local
sidereal time is the Right Ascension of objects currently at the zenith.

See:
http://www.bmumford.com/clocks/sidereal/index.html

--
Bryan Mumford
www.bmumford.com

Convert An Existing Clock By Replacing the 32768 crystal with a 32858
crystal then calibrate it against WWV 1000 HZ tone using a variable
condenser of the right value. Sidereal time is simply one more day within
the same civil year period. so like 32768 * 366.25/365.25 should be the new frequency.



A much cheaper option is to use an phone or tablet app. The best available
and dirt cheap is Emerald Observatory for iPad:


http://emeraldsequoia.com/eo/

They also do an iphone watch app which includes sidereal time displays.

Chris.B wrote:
On Friday, 14 April 2017 06:14:26 UTC+2, Chris L Peterson wrote:

I'd just go with one of the zillion available sidereal clock apps for
a smartphone.

But what will happen when 'Baby' Kim throws an EMP 'tantrum' over the US?

I should start whittling a wooden pendulum now. Just in case.

You can tie on a bag of last week's obsolete iPhonies as a bob. ;-)


If an EMP destroys electronics I will be more worried about the lack of
food, water electricity and prescription medicine than sidereal time
clocks/.

There is no competition between what is true and what is false despite appearances yet it amazes me that our planet's two distinct day/night cycles doesn't garner attention much less the celebration it actually is.

The annual singular twilight at the South pole as Polar night settles in as part of the long day/night cycle as distinct from the daily day/night cycle experienced at habitable latitudes.

https://www.usap.gov/videoclipsandmaps/spwebcam.cfm


There is no such thing as the solar day/sidereal day, there are,however, the dual day/night cycles and the distinct surface rotations behind them and now quite visible with contemporary time lapse -

https://www.youtube.com/watch?v=CFrP6QfbC2g&t=100s

The surface rotation as a function of the orbital motion of the Earth runs parallel with the orbital plane.

That grown adults could manage to project a notion that there are two distinct 'days' running off daily rotation is absurd in the extreme for it obliterates the possibility of expressing a round and rotating Earth and an equatorial speed.