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Keuffel & Esser "Bright Line" Alignment Telescope, model 71-2030, SN 180126

$ 949.87

Availability: 100 in stock
  • Brand: KEUFFEL & ESSER
  • Model: 71-2030
  • MPN: 71-2030
  • Modified Item: No
  • Product: Alignment telescope
  • Condition: Used
  • All returns accepted: ReturnsNotAccepted
  • Country/Region of Manufacture: United States

    Description

    Keuffel & Esser "Bright Line" Alignment Telescope, model 71-2030, SN 180126.
    Here is a vintage (1960's), lightly-used alignment telescope, complete with lamp, power supply and transport/storage box.
    The telescope is in very good condition, both functionally and cosmetically.  The focus knob and micrometer drums turn smoothly, as does the eyepiece focus ring.  The optics are clean and free of scratches/damage.  The heavy chrome-plated barrel is free of rust and damage.  The light-green paint is clean and unmarred but for an engraving between the drums (see pic# 3).  This instrument was only lightly used and well cared for; I know because I managed and maintained an inventory of scopes including this one. It was in acceptable adjustment when last serviced in the mid-1990's.  I am confident that it is fully functional, but before using for any critical task, one ought to have it re-certified / re-calibrated.
    This model is distinguished from its close cousin (model 71-2022) by its right-angle eyepiece and projection illuminator assembly directly behind it ; see pics #5, 6, and 7.  The lamp is powered by coax-cable and step-down transformer; see pics #5 and 8.  The brightness of the lamp (GE #157) can be varied by the transformer's rheostat from nothing to overpowering (not recommended).  Five spare lamps are provided.  The lamp illuminates a negative (dark) reticle with a green cross (see pic# 11).  Note that with the introduction of the projection illuminator, there is no need for auto-reflection target (typical of the model 71-2022) over the front objective (see pic# 4).
    The instrument has two main uses:
    1)  viewing/measuring alignment of features, using the eyepiece reticle and micrometer drums; in pic #9 we are looking at a millimeter scale at short range.  Note that the eyepiece reticle pattern is a simple set of crossed lines; pic #10.
    2)  with the illuminator turned ON, viewing/measuring tilt of optical surfaces (flat, spherical, coated or not).  In pic #11, we are looking the auto-reflection image of the projector's green cross off of a mirrored surface.  Note that the cross coincides with the eyepiece crosshair, which indicates zero tilt.
    Highlights of technical details from the K & E catalog #9 (1979):
    Magnification varies from 4X (near-focus) to 46X at infinity focus.  Fully coated optics throughout.  Eyepiece has an erect image, and a focus-ring for reticle clarity.  Horizontal and vertical micrometers have a range of +/- 0.050", and direct reading to 0.001".  The telescope barrel has an industry-standard outside diameter of 2.250".  Overall length is 22".   Weight is 12 lbs.
    The blond oak box is massive and sturdy, with some external scuffs, overall good condition, and still affords excellent protection for the scope.  The green cloth web belt is still intact and durable, as are the four rubber foot pads.  The serial number on the box matches that on the scope. The box weight is 14 lbs, and is 28" long by 10" high by 9" wide.
    There are no storage compartments within the box for the transformer and cord, so I anticipate shipping in two packages:
    1) the telescope box, over-packed in a larger cardboard box (33 x 12 x 12"), estimated at 31-33 lbs, and...
    2) the transformer with cords, in a smaller cardboard box, estimated at 4-5 lbs.
    Thank you for looking.