ADAPTER M54 MALE TO M42 FEMALE M56 these screws turn the accessory

these screws turn the accessory and therefore alter the collimation

The D2 line at 5890Å is brighter than both Calcium and even Hydrogen Alpha

5 lb counterweights

guidescopes or small telescopes which have finder-style dovetails

flat field for astrophotography

ADAPTER M54 MALE TO M42 FEMALE M56 these screws turn the accessoryThis adapter consists of a male M54 x 0. 75 thread on one end and a female M42 x 0. 75 thread on the other. Optical thickness of the adapter is effectively zero. This is very useful for connecting accessories such as filter drawers or filter wheels with a female M54 x 0. 75 thread to accessories with male M42 x 0. 75 (T2) threads. Specifications Optical length 0 mm (5 mm thread length) Clear aperture 41 mm Outer diameter 54 mm Connection side A Male