DAVIDSON OPTRONICS Model D-613 90 Degree Optical Square

90° OPTICAL SQUARE -- D-613

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.
Features:

Dual-purpose optical square for great flexibility

Kinematic base provides two-plane adjustment

Integral safety guard protects polished surfaces

Certification of accuracy traceable to National Institute of Standards and Technology

Optical Square Schematic As shown in the adjacent 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 arc second
Porro Angle		±3 arc seconds
Flatness		3 surfaces: ⅕ fringe
Surface Quality		80/50 per MIL 13830
Material	Square	BK-7 Glass
	Mount	Steel
Coating Two Sides		Aluminum with protective overcoat per MIL-M-13508
Prism Dimensions	Hypotenuse	2 Inch (51 mm) square
	Coated Sides	1½ Inch (38 mm) square
Overall Dimensions	Height	3¾ Inch (95 mm)
	Width	4.3 Inch (109 mm)
	Length	4.3 Inch (109 mm)
	Height to Prism Center	2¼ Inch (57 mm)
Finish		Ivory Enamel
Carrying Case		Ethafoam lined Finished Hardwood
Prism Weight		3½ pounds (1.6 kg)
Shipping Weight		8 pounds (3.6 kg)

Davidson Optronics, Inc.
Phone: (626) 962-5181
Fax: (626) 962-5188
E-mail: sales@davidsonoptronics.com