NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Precise index correction: was- Eye problems and IE, IC
From: Bill B
Date: 2006 Jul 14, 03:56 -0500
George wrote:
> Bill has told us that he obtains, consistently, a lower value for 4SD
> (where SD = Sun semidiameter) from his observations of adjacent Sun
> images, than he would expect. I can suggest two reasons that ought to
> be at least taken into account, at the precision level he is
> attempting to work to.
Unless I have totally lost it (the key word here being "totally") I believe
Alex and I have been discussing the merit or lack thereof over the past few
days of interpolating Almanac SD to more accurately reflect current values.
I believe I again addressed the problem of elevation in my summary of stage
2 of tests your proposed, posted July 14, 2:08 EDT, 6:08 GMT.
To quote me: "The experimenter cautions that the relationships between
vertical and horizontal measurement change as the body rises or drops in
relationship to the horizon. Therefore changes in elevation of the body
will affect the vertical to horizontal ratio. Care should be taken when
comparing observations taken at different times/elevations. The experiment
was designed to maintain body elevations in a region that minimize these
distortions."
Bill
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From: Bill B
Date: 2006 Jul 14, 03:56 -0500
George wrote:
> Bill has told us that he obtains, consistently, a lower value for 4SD
> (where SD = Sun semidiameter) from his observations of adjacent Sun
> images, than he would expect. I can suggest two reasons that ought to
> be at least taken into account, at the precision level he is
> attempting to work to.
Unless I have totally lost it (the key word here being "totally") I believe
Alex and I have been discussing the merit or lack thereof over the past few
days of interpolating Almanac SD to more accurately reflect current values.
I believe I again addressed the problem of elevation in my summary of stage
2 of tests your proposed, posted July 14, 2:08 EDT, 6:08 GMT.
To quote me: "The experimenter cautions that the relationships between
vertical and horizontal measurement change as the body rises or drops in
relationship to the horizon. Therefore changes in elevation of the body
will affect the vertical to horizontal ratio. Care should be taken when
comparing observations taken at different times/elevations. The experiment
was designed to maintain body elevations in a region that minimize these
distortions."
Bill
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
