>Date: Fri, 22 Jan 1999 00:05:49 -0500
>To: [EMAIL PROTECTED]
>From: [EMAIL PROTECTED]
>Subject: Re: "Analemmatics" on a Gradient
>In-Reply-To: <[EMAIL PROTECTED]>
>
>I have always found it easiest to think of an analemmatic dial as the
downward projection of an armillary sphere onto a surface directly under
the sphere. The projection of the equatorial ring of the sphere would
yield the ellipse of the analemmatic dial, while the projection of the
central portion of the gnomon rod would yield the date line. Since the
direction of projection is straight down, the gnomon of the analemmatic
would always be vertical. If the surface projected to was level it would
yield the "classic" analemmatic dial. It seems to me that the surface
projected to could be tilted in any direction with the only change being in
the shape of the ellipse and the date line. The gnomon would remain
vertical. In fact, I don't believe it necessary for the surface projected
to even be a plane at all; that any shape surface can "catch" the projection.
>
>Charles
>
>
>At 08:04 PM 1/20/99, you wrote:
>>
>>In relation to the recent question/replies, regarding detecting/correcting
>>'errors' in the setting of sundials - is there any feasible way of varying
>>the layout of an "Analemmatic" dial, to cope with it being on a GRADIENT ?
>
