Astromania Bahtinov Mask Focusing Mask for Telescopes - FM120mm for a Tube Outer Diameter (OD) from 125mm-180mm - can be Mounted with the Brass

The Astromania Bahtinov Mask Focusing Mask for Telescopes is a versatile tool that allows for precise focusing on a wide range of telescopes and lenses. It is a thin plastic mask that can be mounted with the brass screws either inside or outside the drawtube. One of the key features of this mask is its compatibility with various telescope models. Customers have reported using it with a 10" Ritchey Chretien telescope, a Nikon 14-24mm zoom lens, a Celestron 8" SCT, a Celestron 127SLT, and a Canon EF 70-200mm f2.8 lens. However, some users have found that it does not fit their specific telescope models, so it is important to measure the diameter of your telescope before purchasing. The mask is lightweight and easy to use, making it a must-have for astrophotographers. It aids in precise focusing and helps achieve sharp images. However, some customers have found it difficult to center and have criticized its overall quality. One common issue raised by customers is that the included screws are too big for the slots, and the rubber sleeves fall off the connector bolts. This can be a bit cumbersome, but some users have managed to make adjustments to make it work. Overall, the Astromania Bahtinov Mask Focusing Mask for Telescopes is a useful tool for astrophotographers, but its compatibility with specific telescope models may vary. It is lightweight and easy to use, although some quality issues have been reported.