76-RH190 Telescopic Transit Square

With Built-In Cross Telescope

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76-RH190 Telescopic Transit Square

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The 76-RH190 has precision telescope optics mounted on a solid-cast bronze horizontal axle which combine to produce a well-balanced instrument with feather-touch controls.  The 76-RH190 is the undisputed "workhorse" of optical alignment, providing tremendous flexibility with substantial time and labor savings.

The versatile Brunson 76-RH190 transit combines the traditional main telescope with a fixed-focus cross telescope mounted in the horizontal axis of the instrument.  This second telescope is fixed at infinity focus to make collimation or autocollimation with another instrument or a mirror quick and easy.  This capability means that the 76-RH190 can be quickly made perpendicular to an optical reference line.  By simply shifting from the main eyepiece to the cross-axis eyepiece, an operator can establish or verify his/her position relative to the basic reference line in seconds. This effectively requires only one technician, where previously two were required.

Patented ball bearing mounts permit accurate sweeping of both horizontal and vertical planes.  The 76-RH190 employs a 194-TM coincidence level for precision leveling. The 194-TM has a 360-degree rotating turret to view the magnified bubble image from any position.

Cross-axis eyepiece

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Available with English, metric, or no micrometer.  Measurements from the optical reference line are taken by using an optical micrometer mounted on the main telescope.  The 76-RH190 comes standard with a model 190 optical micrometer.  To order the transit with a metric micrometer, specify 76-RH190M.  In event that you do not want either micrometer, order model number 76-RH.

The 76-RH190 and 76-RH190M also come with a model 508 light source, a carrying case, set of adjusting pins, instruction booklet, and plastic cover.

 

For additional general information about this instrument, read about our transits on this website.

Specifications

Main telescope:

Length:  14" (with 190 micrometer)

Magnification:  20X at 2" from objective; 30X at infinity

Field of view:  1 degree

Image:  Erect

Optics:  Low reflective, protective coating

Effective aperture:  1.34"

Resolution:  3.9 c/mm (according to NIST test procedure)

Reticle:  Glass, filar/bi-filar pattern (others available)

Focusing Range:  2" to infinity
Cross-axis telescope:

Length:  11"

Magnification:  45X

Field of view:  1 degree

Image:  Erect

Optics:  Low reflective, protective coating

Effective aperture:  1.25"

Resolution:  4.0 arcseconds

Reticle:  Glass, filar/bi-filar pattern (others available)

Focusing range:  Focus is fixed at infinity

Bearings:  Ball type with a runout of 0.000025" or less

Finish:  Two part gray polyurethane enamel (textured)

Approximate Weight:  Instrument, 34 lbs (15.4 kg); instrument and case, 54 lbs (24.5 kg); shipping, 56 lbs (25.4 kg)

Accessories...

  • 160-x Series Coordinate Micrometers
  • 186 Plastic Autoreflection Target
  • 188 Glass Autoreflection Target
  • 190-x Series Optical Micrometers
  • 191 Combination Reticle Projection, Fixed Right Angle Eyepiece Unit (discontinued)
  • 192 Auto-Collimation Unit (discontinued)
  • 193 Right Angle Eyepiece (discontinued)
  • 193-L Right Angle Swivel Eyepiece, Illuminated Adapter
  • 196-1 Combination Projection, Auto-Collimation, Fixed Right Angle Eyepiece Unit

Although the 76-RH190 comes with its own light source, the following light sources will fit on the instrument:

  • 508 LED light source
  • 504 In-line fiberoptic light source (discontinued)
  • 505-110, 505-220 Fiberoptic light sources (discontinued)