Alignment Telescopes

Primarily, alignment telescopes (also called “line scopes” or “line of sight” telescopes) are used to establish and maintain principal optical reference lines. These reference lines may be used by other instruments for a variety of alignment functions (ex., to turn right angles from the reference line), or they may simply be used as measurement references themselves (ex., bore straightness evaluation). In addition, many of them can generally provide the all-important functions of collimation, autocollimation and autoreflection.

Almost all of our alignment telescopes are of the original Keuffel & Esser (K+E) design. These instruments were manufactured and distributed by Cubic Precision before that company joined Brunson Instrument in 1997. At that time, we consolidated our alignment telescope products and adopted the K+E design as our primary product offering.

Our alignment telescopes are made of a very heavy-walled, heat treated, special alloy stainless steel tubing, and concentrically ground inside and out to extremely fine tolerances. Optical systems are precisely installed, and the image is especially bright and clear, having excellent definition. Like all of our instruments, our alignment scopes have the unique ability to prove their accuracy right on the job.


All of our alignment telescope barrels meet A.I.A. specifications, and are hardened and ground to assure good stability and accuracy. The outside diameter is 2.2494" to 2.2497" on all instruments except the 381 series, which has a barrel diameter of 1.7494" to 1.7497".


Some alignment telescopes have built-in optical micrometers, others don't. If the instrument has micrometers, precise measurements of lateral displacement from the line of sight (both horizontal and vertical) can be taken. Micrometers are mounted within the barrel. Different models are available with varying resolutions, ranges and measurement units (metric or English). Explore our range of alignment telescopes to learn more about the various models.

Autoreflection Target

Many of our alignment telescopes have built-in autoreflection targets on the objective (front) end. These paired-line targets are concentric to the line of sight within ±0.001". Three spacings exist (0.008", 0.025", and 0.082") between the paired lines for use at all distances up to 100'. (A 0.092" circle target is also included.) The target may be illuminated from the rear by an autocollimation light source.


Since alignment telescopes have no way to fine-tune the direction of the line of sight, a variety of bases are provided to support and orient the barrel in any desired direction (including straight down). Custom mounting hardware is also available on request. Bases are not furnished with the instruments.


Illumination is supplied by an LED lamp in order to decrease heat distortion and virtually eliminate shock damage. Either 110 or 220VAC may be used with our auto-sensing multi-voltage transformer. A DC power supply is also included with instruments and accessories requiring illumination.


We also provide accessories which allow angular measurement and right-angle sweeps.

Take a look at all of our alignment telescopes…