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Howie Glatter TuBLUG-1.25" Newtonian Collimator

Howie Glatter TuBLUG-1.25" Newtonian Collimator

by Howie Glatter
SKU SI-TUBLUG1.25
CA$224.00 - CA$224.00
CA$224.00
CA$224.00 - CA$224.00
CA$224.00
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  • Barlowed laser collimation of the Newtonian primary with a 1.25" laser
  • Built-in anti-reflection coated Barlow lens
  • Matte-white 45° screen, visible outside the focuser
  • Nylon screws hold the laser without marring
  • Use with a laser in single-beam mode, aperture stop removed
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Howie Glatter TuBLUG-1.25" Newtonian Collimator

    The TuBLUG (Tube + Barlow + Plug) is Howie Glatter's Barlowed laser collimation accessory for adjusting the primary mirror of a Newtonian, made by Starlight Instruments. This version is for 1.25" laser collimators. It is used with a regular laser collimator in single-beam mode on closed tube reflectors.

    How Barlowed collimation works

    The TuBLUG goes in the focuser and the laser collimator inserts into the other side of it. Its built-in anti-reflection coated Barlow lens, mounted in a central axial hole, diverges the beam, so the beam reaching the primary is large and defocused and easily covers the primary's center marker.

    After reflection from the primary, the shadow of the center marker returns to the TuBLUG's white screen. You adjust the primary until the shadow is centered on the screen's central hole. If the center marker is of a certain size, a small red ring of light appears outside the central hole and inside the marker's shadow; making that ring even in thickness helps the adjustment.

    The screen

    The TuBLUG has a matte-white 45° face. It is easily visible from the primary adjustment position, and the TuBLUG can be turned 180° to face the front; it has a cut-out. The screen sits outside the focuser, so it can be seen when collimating the primary from below, and the shadow is more easily seen in twilight or darkness than on a sunny afternoon.

    If you cannot see the screen from below the primary, use a simple 5-6x close-focusing monocular; on smaller scopes you can sit between the bottom of the scope and the focuser and lean one way to turn a knob and the other to see the screen.

    Step by step

    • Insert the TuBLUG in the focuser and tighten the focuser binder against it. Aim the window toward the primary mirror if you will watch the screen from below the primary.
    • Remove the aperture stop from the laser if it has one (you want a large beam) and insert the laser fully into the TuBLUG; nylon screws hold it without marring.
    • Adjust the primary until the shadow of the center marker is centered on the central hole.

    TuBLUG-1.25" or TuBLUG-2"

    Howie makes the TuBLUG for 1.25" and 2" lasers. Choose this 1.25" version for a 1.25" laser collimator.

  • What is the main purpose of the Howie Glatter TuBLUG-1.25"?

    It is used for Barlowed laser alignment of a Newtonian's primary mirror: the shadow of the primary's center marker is returned to the TuBLUG's white screen and you center it on the central hole.

    Do I need to buy a separate Barlow lens to use the TuBLUG-1.25"?

    No. The TuBLUG-1.25" has a built-in anti-reflection coated Barlow lens. You only need to provide your own standard 1.25" single-beam laser collimator to use it.

    How do I use the TuBLUG-1.25" with my 8" f/5 Dobsonian?

    After aligning the secondary, insert the TuBLUG in the focuser and tighten the binder, remove the laser's aperture stop and insert the laser fully, then adjust the primary until the center marker's shadow is centered on the central hole. On smaller scopes, sit between the bottom of the scope and the focuser, leaning one way to turn a knob and the other to see the screen.

    Will the TuBLUG-1.25" damage the barrel of my expensive laser collimator?

    No. The Howie Glatter TuBLUG-1.25" is designed with non-marring nylon retention screws. They hold the laser firmly without marring.

    What if I can't see the shadow on the TuBLUG-1.25" screen from the back of my long telescope?

    If your telescope is too long to see the screen clearly while making adjustments, Howie Glatter's instructions suggest using a simple 5-6x close-focusing monocular to get a clear, magnified view of the screen from a distance.

    Can I use my laser's holographic or crosshair pattern with the TuBLUG-1.25"?

    No. The TuBLUG-1.25" is designed to be used with a laser collimator in single-beam mode. Remove any holographic attachment. You also need to remove any aperture stop from the laser to create a broad, defocused beam that fully illuminates the primary mirror's center marker.

  • Type Barlowed laser collimation accessory (Tube + Barlow + Plug) for Newtonians
    For 1.25" laser collimators
    Fits Focuser (tightened by the focuser binder)
    Screen Large white screen visible outside the focuser
    Lens Built-in anti-reflection coated Barlow lens
    Laser Retention Nylon screws (non-marring)

    • TuBLUG 1.25"

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  • Howie Glatter Warranty