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Thanks for the first hand account.  Your assessment agrees very well
with my thoughts.  I know that heliostats go way back historically so
what does Atherton's device offer that warrants a patent?  Perhaps one
of our UK members will have more information.  Thanks for your insight.

Regards,
Frank Jones
Rochester, NY

On 9/14/2010 1:26 AM, Gary LaPook wrote:
> The article in Cruising World states that Atherton demonstrated his
> heliostat on board a full-rigged tea clipper off Tenerife. This was
> actually aboard the Royal Clipper last October on the transatlantic
> crossing from Lisbon to Barbados with a stop at Tenerife. I was there. I
> saw Atherton's device set up on a small tripod on deck, the device is
> about six inches across. I asked him what it did. He said that it was
> used to measure the altitude of the sun for navigation and that it used
> a pendulous mass to stabilize it and establish the level position. I
> couldn't see how it could be read to a precision of less than a full
> degree so it didn't appear to be very useful for navigation. He seemed
> like a nice old guy so I didn't tell him that pendulous levels don't
> work on shipboard due to accelerations, of course as a physicist he
> should have known that himself. I believe the way it works (although I
> did not study it very carefully since it looked like a non-starter to me
> so I might be wrong) is that the scale, like a protractor, is mounted on
> a base which contains a small mirror and this whole thing is leveled as
> a pendulum in gimbals. Since the angle of reflection equals the angle of
> incidence, the reflected sunlight will shine on the scale at the same
> angle that the sun light hit the mirror and is read against the
> protractor scale. This would work if you could ensure that the mirror
> was horizontal which you can't on a ship and the scale was only marked
> in degrees and there was no way to read it to a greater precision.
>
> So that's what I saw aboard the Royal Clipper.
>
>
> gl
>
> On 9/13/2010 5:56 AM, WF Jones wrote:
>> On page 31 in the September issue of "Cruising World" magazine is a
>> brief announcement entitled "Sun Sights: Easier Than the Sextant". It
>> is not clear to me how this device works. Some list members in the UK
>> may know of the inventor, Ted Atherton, a physicist who resides in
>> Wigan, England. My internet searches came back without a single
>> connect. Thanks in advance for sharing information and thoughts about
>> this device.
>>
>>
>> Regards,
>> Frank Jones
>> Rochester, NY
>>
>>
>>
>>
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