Brunson's 271 tilt collimator provides two reticles ("near" and infinity) for optical instrument testing and evaluation. A top-mounted spirit level vial lets you set the collimator's reticle pattern in a plumb orientation. The infinity target is graduated for angular measurement estimations, with a resolution of 30 arcseconds and a range of ±30 arc minutes in two directions (see illustration below). The paired-line "near" target allows offset measurements when using instruments with micrometers. The steel barrel is hardened and ground, and meets A.I.A. specifications. Backlight illumination for the internal targets is supplied by our model 509 Light Source (included). The 271 may be mounted on bases such as our models 88-6 or 89, or used with a spherical mounting system or "V" blocks. Custom mounting hardware is available on request. The "near" target, shown below left, has multiple paired lines for easy location and registration. The infinity target, shown below right, is graduated for ±30 arc minutes of angular displacement. The image below shows the 271's light source connected for target backlighting
