{"product_id":"takahashi-starbase-or-20mm-orthoscopic-eyepiece","title":"Takahashi Starbase OR-20mm Orthoscopic Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Starbase OR-20mm is a 20mm orthoscopic eyepiece from Takahashi's Starbase accessory line, built on the same 4-elements-in-2-groups design as the rest of the OR series, aimed at low distortion toward the center of the field. It has a 45° apparent field of view, 14mm of eye relief, and weighs 82g. Takahashi lists an overall body size of 33mm x 45mm (diameter x length) for this specific model.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you want a low-power orthoscopic view — wider star fields, lunar overviews, and framing shots before switching to a shorter focal length for detail, with the sharper center-field correction orthoscopic designs are built for.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOrthoscopic 4-element, 2-group design:\u003c\/strong\u003e low distortion, particularly at the center of the field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e45° apparent field of view:\u003c\/strong\u003e a comfortably wide window at this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14mm eye relief:\u003c\/strong\u003e comfortable for eyeglass wearers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e82g weight:\u003c\/strong\u003e light enough to leave a small refractor's balance unaffected.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe four-element, two-group orthoscopic layout is chosen for correction rather than field width — it holds sharpness and low distortion from the center out, which is the trait orthoscopic eyepieces have historically been valued for on the Moon and planets. At 20mm, the OR-20mm sits at the low-power end of the Starbase orthoscopic range, useful as a wide-view complement to the shorter focal lengths in the same series.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eOn a Takahashi FS-60CB (355mm, f\/5.9) the OR-20mm gives about 18x, a wide, bright view for star fields and open clusters. On a TSA-120 (900mm, f\/7.5) the same eyepiece yields roughly 45x — a comfortable low-power view of the Moon and larger deep-sky targets. Divide any Takahashi tube's focal length by 20mm for the magnification on your own setup.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eNot parfocal with the rest of the range:\u003c\/strong\u003e expect to refocus when you swap eyepieces.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — it drops into a standard 1.25” focuser or diagonal.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eLow-power visual observing — wide star fields and lunar overviews, with the low-distortion correction of an orthoscopic design.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow does it differ from the OR-18mm?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBoth use the same 4-element orthoscopic layout; the OR-20mm's slightly longer focal length gives a touch lower magnification and a marginally larger exit pupil on the same telescope.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat telescopes does it fit?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAny Takahashi refractor or reflector with a standard 1.25” focuser or diagonal.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA 20mm orthoscopic eyepiece with a 45° field, 14mm eye relief, and an 82g weight — a wide, low-power view built around the same distortion-controlled optics as the rest of the Starbase OR series. If you're building a full eyepiece set and want help matching focal lengths to your telescope, send us your setup and we'll work it out with you.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047073566831,"sku":"TAK-SBP08060","price":70.07,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/sbp08060_3.jpg?v=1786912698","url":"https:\/\/ontariotelescope.com\/products\/takahashi-starbase-or-20mm-orthoscopic-eyepiece","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}