Ray Tracing

 

The optical design of the NextGEN 0.33X was done with Zemax and optimized for four field points using wavelengths of 450, 550 and 650 nm. The goal was for the smallest blur diameters for the four field points. The system was modeled using the actual optical prescription for a SCT with the inherit aberrations of this telescope. The resulting lens curvatures of this designed were made without adjusting the radii to the optical lab's tool list. Custom tools were made for all surfaces.

 

Click  here to see spot diagram

 

Click  here to see encircled energy diagram

 

Click  here to see ray trace diagram

 

Click here to see field curvature diagram

 

Click  here  for a glossary of terms used in the diagrams

 

 

 

 

Historical Perspective

 

The original 0.33X Maxfield was first introduced almost 14 years ago and was designed for cameras such as the ST-6 and 7 with CCDs deficient in blue sensitivity. The design wavelengths were 500, 650 and 850 nm and was not really intended for RGB imaging which was in its infancy. You can still see on the web a report comparing the old MAXfield to the Meade telecompressor  here. While the reviewer gave the Meade a slight edge over the Optec unit primarily because of cost, it is important to note that the NGM is now price competitive to the Meade unit and has been completely redesigned to perform better optically. The same quality mechanical mounting noted in the review has not changed.