Filter Wheel adapter mismatch

Discussion in 'Filter Wheels' started by theastroimager, Apr 21, 2017.

  1. theastroimager

    theastroimager Standard User

    Mar 13, 2017
    I've purchased and installed SBIG product 10105 (Filter Insert 36mm to 1.25") into my FW8G-STT filter wheel.

    On the Diffraction Limited/SBIG website (, this product is advertised to allow the use of 1.25" filters in the FW8G-STT. Unfortunately, the fit is not quite right.

    When the filter is screwed into the insert, and the insert is installed in the filter wheel, the filter very easily slides around. The flange diameter of the adapter is 35.7mm, while the recess for the filters in the filter wheel is 36.4mm deep, so the filter can slide around.

    The depth of the hole the filters set in is about 3mm, but the height of the flange is only 2.4mm, so there is no "gripping" of the filter when the plate that secures the filters to the filter wheel is screwed down.

    The end result is shown in the video clip which can be seen at...

    So, I'm guessing that either this is not the correct filter adapter, or that there is supposed to be some sort of gasket that helps the cover that holds the filters down to grip the filter?

    Last Friday I talked to Tim, who said he would call me on Monday with the status of this issue. As of today (Friday) I've not heard from anyone.


  2. Tim

    Tim Staff Member

    Sep 25, 2014
    It sounds like you may have forgotten the o-rings? They are size 2-27 and came with the filter wheel (not the inserts). They are placed under the inserts.

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