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A Watch for the Stars!

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A Watch for the Stars!

by Jeff Martin

I will never not know where the moon is ever again!

Background and Biases

I’ve been observing in San Diego since 2003, starting with 8 and 11” GoTo’s.  I think I’ve finally stopped experimenting with equipment and have “frozen” at a Coronado Stacked SolarMax II 60mm, a 17.5” Telekit, a Lightbridge 12, and a C6 on an EZTouch.  All mounts have encoders which I hook up to an iPad via Astro-Devices Nexus wireless adapter.  Plus a couple wide-field achromatics.

I have a pretty strong bias toward the Yes Watches, because they do something I just don’t see other products doing: they let you connect to the sky at a glance 24/7.  Obviously, phone and tablet apps provide more functionality, but it’s not instantaneous (they’re different niches with some overlap).

I’ve been wearing a nice Citizen Dive Watch for about seventeen years before thinking I lost it a few weeks ago.  Having only made about five dives in that period and having rotated through about a dozen telescopes in that same span, I decided to replace the dive watch with an Astronomy Watch. 

With work and parenting decimating my observing time, I was starting, to my chagrin, to lose track of the moon (generally between last quarter and a waxing crescent).  Yes, there are apps and almanacs to keep track of that, but I was dropping the ball, that big shiny darkness-ruining ball.  A watch that connected me with the Moon at all times was a high priority.


The Candidates

The Ultra-Elites.  There are a variety of Lunar-phase watches that cost over $10,000.  I could afford one if I sold all my equipment and took out a loan.  Defeats the purpose; that category was out of my consideration.

Citizen Astrodea - This was one of the more interesting watches, which apparently come in a Lunar Age and a Planisphere model.  They seem hard to find and hard to read (if I have to use a 10x magnifier, I might as well just use an app).

Citizen has at least one Moon Phase watch, in the $1000 range.  The common three-subdials-in-a-big-dial has always seemed too busy for me. 

There are a number of analog watches with a lunar face subdial as well as digital watches with some astronomic functions.  The prices range upward from $20.

Planisphere Watches have an appeal, but they're useful only if you have a magnifying glass.  If you have to use a magnifying glass, you might as well break out the smartphone app.  And, as negligent as I can get about hauling out my telescope, I still pretty much know which constellations are up.

I did buy a fully digital Casio W753D1AV, which has a lunar phase indicator and a tide graph, as well as a readout for what lunar day it is (1-28).  The lunar phase graph has four LCD segments.  I may be losing track of the moon, but I do know what quarter it is.  The LCD segments for the moon and tide are offset behind the "crystal" far enough that I need a strong light at the correct angle to see the data.  It was inexpensive enough to not return it, due to the cost of shipping being a significant fraction of its total cost. I suppose if I'm going do something dirty and scratchy, I won't mind beating the heck out of this watch.

The Winner:  Yes Watch.   By a long shot.

"The Yes Watch changes your relationship with time" says its website.   I found this intriguing, and, ultimately very true.

The Yes Watch bills itself as a lot of things, rightfully.  It is a sophisticated world-wide solar and lunar computer programmed through 2099.  It has a tremendous amount of data and functionality available from its dot matrix digital display, but I'll focus on its wonderful LCD Interface.  I mean, it's cool that I know that it's 1205 days, 15 hrs 4 min and 10 seconds until my first solar eclipse starts (Idaho, Aug 21, 2017), but its the interface that makes this watch uniquely and instantly useful.

Yes Watches come in a variety of cases and bands, the interface comes in two flavors.  The pictures in the review are of my WorldWatch II, which shares the same interface as the Zulu, Kundalina, Inca, and Cozmo watches:


The Yes Watch unique graphic interface shows the following information in a single glance:

*          Time

*          Solar High Noon

*          Sunrise

*          Sunset

*          Proportion of Daylight to Sunlight

*          Moonrise

*          Moonset

*          Lunar Phase (8-segments, which is equivalent to about 44 hours each)

*          Proportion of Moon "up" versus Moon "down"

*          Daylight Savings time "offset"

*          Time Zone Longitudinal offset



When facing South

1.   Rotating the watch so that the "day is level", the 24-hour hand points to the sun.

2.   Rotating the watch so that the Moonrise and Moonset are "level" and the 24-hour hand points to the moon. click here for details.


Looking at the watch over a period of days, you see:

*       the moon phase waxing and waning

*       the Moonrise and Moonset "ring" lag behind the sunrise and sunset

Observing the watch over a period of weeks, you see:

*       The lengthening or shortening of the days - the seasonal changes to daylight proportion.

*       Eight days out of the year (solstices, equinoxes and cross quarter days) you get a special display.  Two days ago, my watch told me it was Beltane.  I didn't know what it was; now I know).

These are the benefits the brilliantly-designed interface delivers with a simple glance - without having to touch any buttons.

Touching buttons provides the same celestial information as above through the LCD Interface for:

*       Dual Time: get the same celestial information for any point on the globe.

*       Time Calculator: get the same celestial information at any time through 2099.


If you want to dive in to the dot matrix digital readout, you get a wealth of information.

For example, a few hours before the Lunar Eclipse of April 15, 2014, I wanted to know what time the Eclipse Maximum was, but was away from the internet (heaven forbid!).  "Oh, yeah: my Yes Watch knows!"  Yes it did, and it was happy to tell me.

Pressing the upper right button shows the date, holding button kicks off a ton of precise information, including

City, Day of Year, Week, Latitude & Longitude, Solar and Lunar data, including rise, transit, and set times as well as New and Full Moon times and current percent illumination.

The User’s Manual is available on the Yes Website, so I won’t reproduce the other details.


Its uniquely intuitive and powerful interface, surrounded by a variety of models to suit your taste make the Yes Watch a beautiful and valuable full-time companion.  There's nothing quite like it!

Additional Information:

Yes Watch LCD Interface

Daylight Savings Time Offset

March 8, 9, 2014: Automatic Changeover to DST.



Standard Time. Note the sunrise/sunset symmetry

Daylight Savings Time. Note the sunrise/sunset 1-hr rotation.

November 1, 2, 2014: Automatic Changeover to Standard Time.



DST.  Note the shorter days, with Solar High Noon later
than 12:00p.

Standard Time.  Solar High Noon and 12:00p retaining only
Time Zone longitudinal offset.

The Winter Solstice: special graphics!




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