End cap for AP 3.5 inch focuser to AP 2.7 inch x 24 tpi inner thread | Starlight

In astrophotography, you want the camera, flat lens and adapter rings to be firmly and perpendicular and not able to sag out of alignment, like in a clamp connection. This end cap with AP 2.7 inch inner thread (24 tpi) from Starlight Instruments is intended for a 3.5 inch focuser (AP 3.5 inch), so you can attach accessories with that threaded connection directly to the focuser.

AP stands for Astro-Physics, which uses this thread size, and tpi stands for threads per inch: the number of threads per inch. That's how you screw a flat lens or a connecting piece with this wire directly on the focus lens.

Check that your accessories really have the 2.7 inch x 24 TPI screw thread, because there are many screw thread sizes that look similar to the eye. If in doubt, measure and check the dimensions. our camera accessories for extension pieces.

If you use an SBIG STL camera, then there is an SBIG STL adapter for the AP end cap.