C.Cooper Sidereal Time Pocket Watch - Swiss Made

Discussion in 'European & Other Pocket Watches' started by Springdale Ben, May 14, 2020.

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  1. Springdale Ben

    Springdale Ben Registered User

    Jun 21, 2019
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    Hi

    I have an interesting silver pocket watch that tells Sidereal time and I was hoping someone can help identify the movement maker?

    The dial and movement are both signed "C.Cooper 93 Hatton Garden London, Swiss Made". I assume Cooper is the retailer as I can't find any information about him being listed as a watchmaker

    There are some numbers under the balance that read "3 834 1" Swiss Flag and then in smaller numbers "10489".

    Please see pictures attached. It runs like a train and I didn't want to try and stop the balance to photograph it.

    Thanks in advance

    Ben

    IMG_7206.JPEG IMG_7207.JPEG IMG_7210.JPEG IMG_7205.JPEG IMG_7202.JPEG IMG_7203.JPEG IMG_7204.JPEG
     
  2. eri231

    eri231 Registered User

    Jan 13, 2012
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    Roskopf perfected watch with direct second.
    regards enrico

    CH_10489_A.png
     
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  3. Springdale Ben

    Springdale Ben Registered User

    Jun 21, 2019
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    Thanks Enrico - so it's a Roskopf pocket watch?
     
  4. JTD

    JTD Registered User

    Sep 27, 2005
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    #4 JTD, May 15, 2020
    Last edited: May 15, 2020
    As enrico has said, Swiss patent No. 10489 is in respect of a movement with the Roskopf system. The patent was granted in 1895 to Ls.-Marcelin Grosjean of Bienne (Switzerland).

    Many Swiss watch makers made watches with the Roskopf sytem.

    It would be hard to say who made yours. Cooper calls himself 'sole maker' on the dial, but he clearly didn't make the movement. Perhaps he bought in the movement and cased it. Are there any case markings?

    JTD
     
  5. eri231

    eri231 Registered User

    Jan 13, 2012
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    can't define a Roskopf, but a distant and evolved cousin this yes.
    This movement was made by Brandt & Hofmann of Biel, better known as the Orion Watch. and can be called a high grade of "Roskopf-like". a drawback of the wheel train used by Roskopf was that the minute register turned in the opposite direction, to the left, a problem solved later with the addition of an intermediate wheel. While with Marcelin Grosjean's patent no intermediate wheels were needed. With the same patent it was possible to have the seconds in the center. But the real question is a real sidereal time or not? Solar time (24h) sideral time (23h56m)
    regards enrico
     
  6. Springdale Ben

    Springdale Ben Registered User

    Jun 21, 2019
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    Hi

    JTD - case is marked "K&L" with London import hallmarks for 0.935 silver.

    Thanks Enrico - it seems to be sidereal time. I set it at 6.00pm yesterday, it's currently 12.20pm here and the watch is reading just past 12.22pm. So at 6.00pm it should be reading roughly 6.04pm if it's sidereal? I guess with a watch of this age it's not going to be perfectly accurate anyway.

    Thanks

    Ben
     
  7. JTD

    JTD Registered User

    Sep 27, 2005
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    Could you post a photo?

    JTD
     
  8. Springdale Ben

    Springdale Ben Registered User

    Jun 21, 2019
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    Sure - see pictures attached.

    Thanks

    Ben

    IMG_7230.JPEG IMG_7231.JPEG
     
  9. gmorse

    gmorse Registered User
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    Jan 7, 2011
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    Hi Ben,

    Certainly the 'three bears' and the '0.935' of the Swiss silver standard for the British market, but no London import marks that I can see.

    Regards,

    Graham
     
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  10. PatH

    PatH National Program Chair
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    Dec 5, 2014
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    Is the pictured watch the one advertised by Charles Cooper in this 1899 Google publication? The ad says it is rated to 5 beats/sec, but can be rated to 4 at an extra cost of 15s (the watch sold for 50 shillings).
    The Observatory
     
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  11. Springdale Ben

    Springdale Ben Registered User

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    Hi Pat - are you able to screenshot the advert, I can't seem to view it through Google Books.

    Thanks
     
  12. musicguy

    musicguy Moderator
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    Nice find Pat!


    Rob
     
  13. PatH

    PatH National Program Chair
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    Courtesy of Google Books - The Observatory January (blue tinted paper) and December (white paper) issues. Other instances of these ads are included in the various monthly issues. Early in the year the 1st ad appeared, then at the end of the year, the 2nd example.

    C Cooper The Observatory 1899-01.png C Cooper sidereal The Observatory 1899-12.png
     
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  14. Springdale Ben

    Springdale Ben Registered User

    Jun 21, 2019
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    This is great, thanks Pat. I can't tell if the watch beats 4 or 5 times per second, although it ticks very loudly! See video below...

     
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