{"product_id":"open-box-es-field-flattener-for-f-5-to-f-7-refractors-1","title":"Open Box ES Field Flattener For f\/5 to f\/7 Refractors","description":"\u003ch3\u003ePRICE DROP!  Was $130, now just $75!\u003c\/h3\u003e\n\u003ch4\u003eCondition:\u003c\/h4\u003e\n\u003cp\u003eThis is an open box return in excellent condition. The outer body is unmarked and the optics are clean. Though, this is missing and \u003cspan style=\"text-decoration: underline;\"\u003edoes not include\u003c\/span\u003e the M48 adapter. Otherwise it is practically new and includes the original box. \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch4\u003eDescription:\u003c\/h4\u003e\n\u003cdiv class=\"product-main\"\u003e\n\u003cdiv data-product-description=\"\" class=\"product-description rte\"\u003e\n\u003cdiv id=\"tab-0\" class=\"tab-pane tabactive\"\u003e\n\u003cdiv class=\"tabcontent\"\u003e\n\u003cul\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eThis is a field flattener for refractor-type telescopes with a focal ratio of f\/5 to f\/7\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eCauses no change to the telescope focal length\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003e2-inch barrel to easily attach to a two-inch focuser\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eFully multi-coated optics\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eT-ring thread on the device so a T-ring can be used to easily attach a DSLR camera or a dedicated astrocamera\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003e38 mm of clear aperture\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eRequires 55mm (+\/-2) of back focus\/spacing between the device and the camera sensor\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003ePremium high glossy anodizing finish\u003c\/li\u003e\n\u003cli data-open-accessibility-text-original=\"16px\"\u003eIncludes both M42 and M48 adapters\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-open-accessibility-text-original=\"16px\"\u003eWhen doing astrophotography with refractor-type telescopes, the faster the focal ratio the more field curvature becomes a problem. Field curvature will appear in the corners of astrophotographs, making the stars smear perpendicular to the axis of the image. This is called coma -- coma is Latin for comet, because the stars look like comets. The more the curvature, the closer to the center the coma appears. The larger the sensor, the worse the coma.\u003c\/p\u003e\n\u003cp data-open-accessibility-text-original=\"16px\"\u003eAstrophotographers can easily correct the coma by using a field flattener – an optical device that goes between the telescope and the camera. Field fatteners are not interchangeable, because these devices are designed to work with a small range of focal ratios.\u003c\/p\u003e\n\u003cp data-open-accessibility-text-original=\"16px\"\u003eThe Explore Scientific field flattener is designed to work with telescopes with focal ratios between f\/5 and f\/7. Our device requires 55 mm (+\/-2 mm) of spacing between the back of the device and the camera sensor.\u003c\/p\u003e\n\u003cp data-open-accessibility-text-original=\"16px\"\u003e\u003cmeta charset=\"utf-8\"\u003e\u003cstrong\u003eFits the following Explore Scientific telescopes:\u003c\/strong\u003e\u003cbr\u003eDAR1020765-01\u003cbr\u003eDAR127065-02\u003cbr\u003eDAR152065-01\u003cbr\u003eES-ED0806-02\u003cbr\u003eES-ED10207-02\u003cbr\u003eFCD100-0806-01\u003cbr\u003eFCD100-10207-02\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":49709025231107,"sku":"OB2511-ES-FF2F5\/F7","price":75.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/E9EE727E-717B-4CED-B0F7-95539F95A49F.png?v=1764203588","url":"https:\/\/milehighastro.com\/products\/open-box-es-field-flattener-for-f-5-to-f-7-refractors-1","provider":"Mile High Astronomy","version":"1.0","type":"link"}