Friday, March 18, 2016

The Ansonia Sunwatch & Instructions

     It's a rare day I come across an ad for something I actually own, especially when it's as rare as this gem.  The Sunwatch is a pocket sundial with a compass to orient yourself properly with the sun.  I just happen to have found one of these when I was cleaning out my dad's house and as far as I know, it belonged to my grandfather.

     Originally invented for the use of Boy Scouts they were sold in various technical publications as well from the early 1900's through the late 1920's.  My particular one was made around 1921 by Outdoor Supply Company, who bought the patent from Ansonia after WWI.  The construction is cheap by 1920's standards, stamped sheet metal with a transfer face and plastic case German compass but compared to the cheap China world we live in today it's actually made to withstand the rigors of outdoor life.  I didn't get an outside shot of mine but suffice it to say that it's been well worn for being in someone's pocket for years.

     To use the Sunwatch you need to know on which line of Latitude you are on.  On the lid there is a cities list on the left for most major cities in the us.  There is also a correction in + or - minutes that you need to take into account when figuring the time.  On the left is an equation column that give you time corrections in + or - due to date.  Of course the Sunwatch was made before we stupidly decided to go back to Daylight Savings time in the 70's so there is no correction for that save subtracting an hour from the time the device gives you.

     So to figure my time I live in Jacksonville, Fl which is on the list and indicates I need to add 28 minutes correction, it is also March 11th and I need to add another 10 minutes for a combined total of +38 minutes correction.  If we look at the face of the Sunwatch you'll see there's markings along the top arc of the compass that indicate minutes correction in either plus or minus. So all I have to do is point the compass about at the 40 mark on the right and that would do it.  I set the

angle of the arm at the 35°LAT mark and and read the time from the outer 35° circle which gives me a time of about 2:05pm.  This was before Spring "forward" this Sunday so I subtract and hour and I get 1:05pm which is very close to the actual time of 1:01pm.  Of course it's more general than a wristwatch, it's a sundial, but I find it's accuracy quite astonishing.  For me it's nothing more than a novelty, an heirloom of my family's past, it will never replace my cellphone as my timepiece, but it is a wonderful instructional tool and even now I would say that it could find a place in a Scout's gear as one should always be prepared.


  1. Just found one cleaning out my Dad's house lol

  2. That is a very interesting device. I have been wanting to get a book on sundials and learn more about the theory behind how they work. I was wondering about the correction factor, though, that you mentioned. The key written at the bottom seems to indicate that you should add (for Jacksonville) 10 minutes to the sun time, not the arc correction. So the arc correction would have been 28 minutes then whatever time was read on the dial, add 10 minutes to that. I don't know, just wondering if that was the intent. Also the shadow is thick, I could not tell from the photo if it goes to a point at the tip end for more precise reading. Thanks for writing about the dial, I enjoyed it.

  3. I have one as well I'd be willing to sell

  4. Many thanks for your piece. I've just purchased the version made for the British/Irish market.

  5. I just bought a storage unit and found one...

  6. Replies
    1. I did not know it was made in 1920's
      My father gave mind in 1960's
      It came with a purple pouch and no book.
      The plate give clue how to use the watch.
      My longitude is 120 all had to to adjust for time month that plate.

      It still keeps good time for being over a 100 years old.


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