Aluminum Alloy Mask 84-115mm 84-115mm Monocular Telescope

Place the over the end of your telescope, then locate a bright star near your target, take a 3-5 second picture and view the diffraction spikes. Change your focus, take another picture and again, view your diffraction spikes.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.Masks now feature 3 holes which can be attached with 3 screws to prevent the mask from falling all the way to the groundPerfect focusing for your CCD, DSLR or Webcam in secondsLight weight so you wont upset the balance on your scopecover allow the mask to be simply attached to any telescopeType: MonocularModel Number: for Telescope monocularAstronomical telescope: for telescopeBahtinov Mask: for Astronomy telescopeAstronomy: Excellent Qualitycolour:blackmaterial:Aluminum alloysize:Product size: 80mmSuitable for caliber size:84-115MmWeight:32gPackage Contents:1*Telescope Focusing MaskNote:1,When you buy it , you need to check your out-diameter of the tube .Not just the Objective lens diameter.you need to put the item one the tube.2,if you don't know which size should to choose you can ask me before buy it3,The size is not the diameter of the item, pls check the measurement way.Only the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.