{"product_id":"svbony-1-25-0-5x-focal-reducer","title":"SVBONY 1.25″ 0.5x Focal Reducer","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-1_20250807110655_3023_20260810100140_7034.webp?v=1791670296\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SVBONY F9154A is a 0.5x focal reducer in a 1.25″ filter-style cell. It threads onto the M28.5 x 0.6 filter thread of an eyepiece or a 1.25″ camera nosepiece and roughly halves the effective focal length, giving a wider field at lower magnification. The two-element optic is fully multi-coated, the sleeve is all-metal aluminium alloy, and the cell is 20 mm tall with a female M28.5 thread at the rear so a filter can be added.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if your telescope's long focal length makes it hard to fit large targets such as the full Moon in the field, or if you image with a small-sensor planetary or EAA camera and want a wider field and shorter exposures.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-2_20250807110742_2637.jpg?v=1791670296\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.5x reduction:\u003c\/strong\u003e cuts the telescope's focal length by about half for a wider view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo-element optics:\u003c\/strong\u003e fully multi-coated on all air-glass surfaces for contrast, including on long exposures.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads both ends:\u003c\/strong\u003e male M28.5 x 0.6 at the front, female at the rear for a 1.25″ filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAll-metal body:\u003c\/strong\u003e aluminium alloy sleeve, 20 mm total height.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-3_20250807110742_3087.jpg?v=1791670297\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe reducer works by converging the light cone sooner, so the eyepiece or sensor sees a shorter effective focal length. With a filter-thread reducer the actual reduction depends on the distance between the reducer and the focal plane: the further it sits from the sensor or eyepiece field stop, the stronger the reduction. SVBONY rates it at 0.5x.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-4_20250807110742_3647.jpg?v=1791670297\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar observing:\u003c\/strong\u003e fitting the whole Moon in the field on long-focal-length scopes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSmall-sensor imaging and EAA:\u003c\/strong\u003e a wider field and shorter exposures with planetary-style cameras.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-power visual views:\u003c\/strong\u003e larger open clusters and extended objects.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-5_20250807110742_3991.jpg?v=1791670296\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread:\u003c\/strong\u003e M28.5 x 0.6, the standard 1.25″ filter thread on eyepieces and camera nosepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e a 1.25″ filter threads into the rear.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eC-mount option:\u003c\/strong\u003e SVBONY also offers this reducer with a C-mount adapter as a separate style; get in touch if you need that version.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-6_20250807110742_2678.webp?v=1791670296\" alt=\"SVBONY F9154A 1.25″ 0.5x focal reducer for wider-field observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSmall fields:\u003c\/strong\u003e a filter-thread reducer suits small sensors and narrow-field eyepieces best; on larger sensors the edges of the field show vignetting and off-axis aberrations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e SVBONY does not publish a weight for this reducer.\u003c\/li\u003e\n\u003c\/ul\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 threads onto an eyepiece or camera nosepiece like a filter.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs it for visual or imaging?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBoth. SVBONY presents it for wider-field visual use and for CCD\/CMOS imaging.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I still use a filter?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes. The rear female M28.5 thread accepts a 1.25″ filter.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 1.25″, two-element, fully multi-coated 0.5x reducer in a 20 mm metal cell that threads on like a filter to widen the field for observing and small-sensor imaging.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"Focal Reducer","offer_id":67722265886831,"sku":"F9154A","price":21.65,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9154a-1_20250807110655_3023_20260810100140_7034.webp?v=1791670296","url":"https:\/\/ontariotelescope.com\/products\/svbony-1-25-0-5x-focal-reducer","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}