90° OPTICAL SQUARES -- D-613
As shown in the above sketch, the internal 90° angle, when using this instrument as a Porro prism, permits viewing the image through the hypotenuse. The Model D-613 aids in quickly positioning two autocollimators at 90° to each other by utilizing the precise right angle surfaces. |
Detailed Specifications:
| 90 degree Angle | ±1 second | |
| Porro Angle | ±3 seconds | |
| Flatness | 3 surfaces, 1/5 fringe | |
| Surface Quality | 80/50 per MIL-O-13830 | |
| Material | Square | BK-7 Glass |
| Mount | Steel | |
| Coating Two Sides | Aluminum with protective overcoat per MIL-M-13508 | |
| Prism Dimensions | Hypotenuse | 2" square |
| Coated Sides | 1½" square | |
| Overall Dimensions | Height | 3¾" |
| Width | 4.3" | |
| Length | 4.3" | |
| Height to Prism Center | 2¼" | |
| Finish | Ivory Enamel | |
| Carrying Case | Ethafoam lined Finished Hardwood | |
| Prism Weight | 3½ pounds | |
| Shipping Weight | 8 pounds | |
Davidson Optronics, Inc.
Phone: (626) 962-5181
Fax: (626) 962-5188
E-mail: sales@davidsonoptronics.com
From an economy standpoint, the Model D-613 90 Degree Optical Square does the work of two accessories, but at the cost of only one. It is a precise 90° Optical Square (or 90° Angle block) and it is also a Porro prism with sensitivity in elevation only. Fine adjustment is accomplished with 120 threads per inch leveling screws. The base safety guards protect the polished optical surfaces and simplify handling.