----- Original Message -----
From: "Patrick J. Madden" <unvat001@...>
To: <guide-user@yahoogroups.com>
Sent: Monday, December 12, 2005 6:32 PM
Subject: [guide-user] Trigonometry Question


>
> I am trying to set up a 16" Ritchey with a FL of 3650 mm. Through the
> T-Point program, I have discovered that there is a lack of orthogonality
> between the optical axis and the declination axis. The amount is 415 arc
> seconds, or about 7 arc minutes. Now, if the mounting rings are 16"
> apart, how big of a shim do I need to put under one of them to introduce
> an angle of 7 arc minutes?
>

Hi Pat,

You have a right-angled triangle with an unknown "height" (x), a base of
16", and an angle of 415".

We therefore have:

tan(415") = x/16

ie x = 16*tan(415")

x = 0.032"

so you need a shim which is 0.032", or 0.82mm in height.

Regards,

Chris