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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Big Full Moon and Perigee Spring Tides
From: Richard B. Langley
Date: 2011 Mar 19, 13:02 -0300
From: Richard B. Langley
Date: 2011 Mar 19, 13:02 -0300
Hate to nitpick, but best not to call it the "Daiichi Problem." "Dai ichi" just means "number one" in Japanese. It is certainly not the West Coast's number one problem. Maybe the "nuts" are. ;-) -- Richard Langley On 19-Mar-11, at 10:57 AM, Apache Runner wrote: > Frank - > > I'm at Cape Cod today, and we do have some big tides today, so that > much is interesting. > > I did a bit of digging on the definition of high astronomical tide > and low astronomical tide. There is a move to try to standardize > this for bathymetric datum for all charts, but a) the US is still > using MLLW (mean lower low water) and b) the definition of > astronomical tides is a bit elusive. > > In an operational definition, it seems to be the 'lowest' tide > recorded over some longish time period. A more thorough > definition in other countries seems to be based on the metonic cycle > of 19 years. A even more thorough definition would be the earth > at perihelion, the moon at perigee, the sun and moon in conjunction > and both the sun and moon at zero declination, which my source tells > me will next happen in 6580 AD. I don't think any country uses > this definition. > > Regarding the west coast panic, my cousin who lives in San Francisco > e-mailed me, asking about potassium iodide tablets. I resisted > the urge to reply "R U NUTS?", and instead composed a thoughtful > message with all the reasons why the Daiichi problem cannot affect > the US West Coast. > > John H. > > > > On Sat, Mar 19, 2011 at 5:20 AM, Frank Reed> wrote: > An article from S&T about some of the exaggerated claims regarding > the Full Moon today: > http://www.skyandtelescope.com/observing/home/118265299.html > > It makes a simple, excellent point: "When it comes to science > stories, if you don't know it in numbers, you don't know it at all". > > There's also some good advice on "frantic aunts" forwarding brain- > dead emails. > > -FER > > > ---------------------------------------------------------------- > NavList message boards and member settings: www.fer3.com/NavList > Members may optionally receive posts by email. > To cancel email delivery, send a message to NoMail[at]fer3.com > ---------------------------------------------------------------- > > > > > -- > Keeping up with the grind ----------------------------------------------------------------------------- | Richard B. Langley E-mail: lang@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3 | | Fredericton? Where's that? See: http:// www.fredericton.ca/ | -----------------------------------------------------------------------------