Note on ray projection in AutoCad for use with Meade 8" OTA Drawing.

1.	All incident light arriving at the Corrector Plate is Parallel.
2.	Only the Green Vector passes through the Corrector without Refraction.
3.	Only use the Rays exiting the Corrector on the inside of the OTA as references.
4.	After moving any of the Optical elements, X, Y or Rotation always re project the Rays.

5.	After moving Optical elements, do the following.
	5.1	Use the Extend or Trim Command to set the Rays in 3. to contact the Optical 		surface.
	5.2	Use the Mirror Command to Mirror the incident Ray about the Incident Point to the Centre of Curvature.
	5.3	Extend or Trim the Reflected Ray to contact the next Optical Surface.
	
6.	Use and Repeat the above sequence until the Ray crosses the OTA Axis.

If the Primary or Secondary Mirrors are Tilted or Rotated or Shifted Off Axis, then the intercept of Rays will be shifted off axis as will be shown by the Ray Intercepts at the new focal Point.

The curvature of the Mirrors and their Positions have been obtained for a particular LX200GPS 8" that was manufactured September 2005.  This OTA has the NEW Secondary Mirror assembly and Collimating Assembly.

The OTA has UHTC coatings.

Laser Vectors were 650nm wavelength and 0.25 mm diameter.

The drawings are subject to change and update as new elements are measured and added.

Collimating screws, Primary Mirror Focuser & Micro focuser will be added soon.

Enjoy

Conrad.

mail to:  conrad@crcm.net