Focuser on Celestron (C11) blocked due to too long screws & foreign objects

Product Description
(N)One screw is loose or too long on SCs & MAks

Problem:
If you want to attach mounting rails to the tubes of SCs & MAks, this is usually possible without any problems, as long as you pay attention to two things:

Length and position of the mounting screws

Avoid foreign objects (chips, dowels)

Length of the screws
If the mounting screws are too long, they can affect the functionality of the telescope. This is especially true for telescopes where the primary mirror must move during focusing (Schmidt-Cassegrains, Maksutovs). In these cases, no screw should protrude through the tube in front of, behind, or next to the primary mirror path! Therefore, if you notice limited focusing after tightening the mounting screws, immediately and absolutely check the primary mirror and the immediate surrounding edge of the tube. Remove the screw(s) that are too long.

Foreign Objects in the Tube
When drilling, care must be taken to ensure that no foreign objects (such as drilling chips or even dowels (or remnants)) enter the interior of the tube.

Possible Solutions
1) Always check the length of the screws and select the correct length based on the tube edge. Generally, screw connections around the primary mirror should be avoided. The tube length is usually sufficient to attach rails elsewhere.

2) Never use dowels; due to physics and the thin tube edge, they do not provide a suitable, stable connection. ALWAYS use metal screws with a fine thread. Use a vacuum cleaner when drilling to remove drilling chips. And while drilling, repeatedly lift the drill bit out of the housing to remove any drilling chips.

If the child falls into the well, or a foreign object gets into the tube of a MAK or SC, you don't have to immediately remove the Schmidt plate or lens. The foreign object can often be removed via the diagonal mirror entrance—or, in the case of SCs with a camera mount, the secondary mirror—using a narrow vacuum hose or a small gripper.
If the foreign object is on the primary mirror or the glass plate, gently shake the telescope slightly so that the object of the disturbance rests in the center section of the tube. Never vacuum, grab, or wipe the mirror or glass plate!

If that's too fiddly for you, feel free to contact us for rail mounting and inspection (for a small fee).