Aluminum Alloy Bahtinov Focusing Mask Telescope Caliber Fixed Diameter 60-270mm

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Aluminum Alloy Bahtinov Focusing Mask Telescope Caliber Fixed Diameter 60-270mm

Descriptions: 1. The Bahtinov Mask Made of aluminum alloy, not plastic. And it has whole anodizing aluminium process, which is durable and has good performance in long-term use. 2. This focusing mask can be used for a variety of purposes, such as camping, hiking, fishing, hunting, and other outdoor activities. 3. Masks now feature 3 holes which can be attached with 3 screws to prevent the mask from falling all the way to the ground 4. Perfect focusing for your CCD, DSLR or Webcam in seconds 5. Light weight so you wont upset the balance on your scope 6. Suitable for telescopes front end diameter 60mm to 330mm according to different sizes 7. Universal adaptation, 3 bolts with plastic cover allow the mask to be simply attached to any telescope 8. Aluminium alloy material thickness: 1 mm 9. Color: Black

Note :

1. When you buy it, you need to check your out-diameter of the tube. Not just the Objective lens diameter, because you need to put the item on the tube.

2. If you don't know which size should to choose you can ask us before buying it, Thanks

3. Place the Bahtinov Focus-Mask over the end of your telescope, then locate a bright star near your target, take a 3-5 seconds picture and view the diffraction spikes. Change your focus, take another picture and again, view your diffraction spikes. Is the center spike moving further from center? Then change the direction your focusing and try another picture. Watch the direction the spikes are moving and when the center spike passes the middle of the other two spikes, change direction and fine tune your tuning knobs until the center spike is in the middle. Your now in perfect focus.

Normal Size

Telescope tube min outer diameter(appr.)

tube max inner diameter(appr.)

Sample compatible telescopes

A27-60

60mm-90mm

60mm

90mm

small camera lenses or small refractors like the TS 50mm APO. INED70 or other 60-80mm refractors…