waltham side real and astrinomical

[lollyb1984]

Im trying to find out about my side real and astrinomical watches can any one help ? thanks the serial numbers are 18028503 for the side real and the astrinomical is 18091062 the are both 19 jewles aww company waltham mass on both cases , hope someone can help me lolly

[Larry Treiman]

Hint: If you want to do a search, either on this MB or Google, the words are "siderial" and "astronomical" and I believe that Waltham called them Astronomical-Siderial watches. They are great watches to have! Someone should be along soon who is more familiar with what all that means.

[Larry Treiman]

Oops! Spelling alert!! When I typed the above post, I thought that the word was spelled :Sidereal" (one word). But when I checked the serial numbers in the Waltham list (the "Gray" book., both listings showed it spelled "Siderial" so I changed it. But the more I thought about it and pictured the word in my mind, I wasn't so sure. I was on my way out, but when I got back I looked it up in the dictionary and there it is spelled Sidereal.

I'm sorry to have to say that the Waltham serial number list (the "Gray" book) isn't noted for accuracy, so if you are doing a search, use the sidereal spelling. As for astronomical, the "Gray" book abbreviates it as "Astronom."

[burt]

Sidereal Time is the time it takes the earth to make a complete rotation on it's axis.This completion is called a sidereal day.Sidereal time is 3 minutes and 55.91 seconds shorter than the mean solar day.This is about equal to 9.83 seconds shorter per hour.

[Tom McIntyre]

The reason for the difference between a solar day and a sidereal day is that the earth also orbits the sun. That annual orbit around the sun constitutes an additional rotation of the earth. In the same way, the moon is not stationary on its axis but rotates once every 28+ days as it orbits around the earth. In the case of the moon, the phases of the moon are an indication that the same part of the moon is not facing an external reference object continuously the same way. That is, if you were standing on the sun and looking at the moon/earth system, you would see the moon rotate once in each orbit.

[Fred Hansen]

The 1892 model Waltham "Sidereal" and "Astronomical" are scarce, high grade, and desirable watches. The examples of these watches I've seen have been basically the same apart from the difference in "Sidereal" or "Astronomical" dial marking. Congrats on having an example of each of these great watches!


Here are some photos and details of an "Astronomical" that I had last year ...

http://fhwatch.com/showitem.php?desc_fn=soPW10306.txt

... and I would enjoy seeing photos of your two watches if possible.