Astromania Bahtinov Mask Focusing Mask for Telescopes - FM200mm for a Tube Outer Diameter (OD) from 215mm-260mm - can be Mounted with The Brass Screws Inside or Outside The drawtube

This is a must have piece of equipment for any astrophotographer. It works easily and is light weight. Don’t leave home without one for the night!

this is a good batinov mask for a 4 inch telescope, a must to focus for astrophotography at a good price.

It works. Looking through the eyepiece you can clearly see the pattern, but you don't need it for that. You need it for the camera. I can't see the pattern looking through the camera, but if I take a short photo, (these are 10-11 seconds) you can see the pattern. I mounted it to a thin plywood board that slides into the telescopes cover slot for easy installation and removal.

Purchased for an Explore Scientific ESD80 and it's actually a little small but does the job. Focusing is quick & easy as long as you use a bright star.

At first, I did not realize that the pegs are actually in 3 pieces, a rubber outer sleeve, a threaded screw, and threaded hexagonal, for lack of a better word, nut. I wish that the unit came with instructions.

I haven't had a chance to use this thing yet. Never used one before either. However it does fit my lens hood well. I'll find out how good it is when the summer gets here. In the Pacific Northwest the winters are too miserable to sit outside taking long exposures of the sky.

The included screws are too big for the slots. Other than that it looks ok. I'll keep it and widen the slots but the correct screws would have been nice.

Place this on your camera lens or telescope to help you nail focus on the stars, and planets. Take it off, and view the sky object(s) or capture your astro-photographs.

Not much to say, works great.

Works perfectly as expected. Just be sure to order for the outside diameter of your tube.

Arrived quickly and was exactly as described.

sturdy and easy to work with

well built ..easy to use