{"product_id":"bahtinov-mask-for-140mm-optics-oelj","title":"Bahtinov Mask for 140mm Optics","description":"\u003cp\u003eThe Bahtinov mask is used to focus small telescopes accurately. Although masks have long been used as focusing aids, the distinctive pattern was invented by Russian amateur astrophotographer Pavel Bahtinov.\u003c\/p\u003e\n\u003cp\u003eSimply place the mask in front of the main optic of your telescope and take a picture. Look at the diffraction spike pattern and continue until the spikes are even. Using a Bahtinov mask is the easiest way to get into focus.\u003c\/p\u003e\n\u003cp\u003eThis 140mm mask is great for 125mm - 130mm class telescopes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFits dew shields with an outside diameter of 153-192mm\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMade in Canada\u003c\/p\u003e","brand":"Starfield Optics","offers":[{"title":"Default Title","offer_id":42289647845447,"sku":"FM-140","price":46.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0648\/1631\/6487\/files\/BMmask__89966_0648e79b-0703-4256-929a-b90025bcf793.jpg?v=1766465348","url":"https:\/\/starfieldoptics.com\/products\/bahtinov-mask-for-140mm-optics-oelj","provider":"Starfield Optics","version":"1.0","type":"link"}