{"product_id":"rb-focus-carbon-fiber-double-vane-spider","title":"RB Focus Carbon Fiber Double-Vane Spider for Newtonian Telescopes","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDouble-vane spider design\u003c\/li\u003e\n\u003cli\u003eUltra-thin 0.5 mm vanes\u003c\/li\u003e\n\u003cli\u003e3K carbon fiber and stainless steel construction\u003c\/li\u003e\n\u003cli\u003eImproves collimation stability against temperature changes\u003c\/li\u003e\n\u003cli\u003e4-point collimation system with included Bob's Knobs\u003c\/li\u003e\n\u003cli\u003eAvailable for 150, 200, 250, and 300 mm Newtonians\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eRB Focus Carbon Fiber Double-Vane Spider for Newtonian Telescopes\u003c\/h2\u003e\n      \u003cp\u003eThe RB Focus Carbon Fiber Double-Vane Spider is a secondary mirror spider for Newtonian telescopes, made of 3K carbon fiber and stainless steel. Its two 0.5 mm vanes are spaced 10 mm apart. RB Focus says the thinner vanes reduce weight while improving the rigidity and stability of the secondary support, so collimation holds after long use or transport to the field. A 4-point collimation system with Bob's Knobs makes secondary alignment easier.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003e0.5mm Vanes and 3K Carbon Fiber Construction\u003c\/h3\u003e\n      \u003cp\u003eRB Focus says the carbon fiber spider is very resistant to temperature changes, which helps collimation and focus stay where you set them as the temperature varies. The vanes are only 0.5 mm wide.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eDiffraction Pattern of the 10 mm Spaced Vanes\u003c\/h3\u003e\n      \u003cp\u003eRB Focus explains that, contrary to what the double vanes suggest, stars do not show doubled spikes: at focus the patterns cancel out into fine, elongated spikes that give stars a subtle, stylized look. RB Focus adds that this pattern can also be used to confirm focus.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003e4-Point Secondary Adjustment with Included Bob's Knobs\u003c\/h3\u003e\n      \u003cp\u003eThe spider has 4 collimation points, factory-fitted Bob's Knobs and a modified collimation clutch. RB Focus says this makes it much easier to square the focuser and collimate the secondary mirror, aligning it in a few seconds.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the main benefits of upgrading to the RB Focus Carbon Fiber Spider?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eRB Focus highlights its rigidity and stability, its resistance to temperature changes (helping collimation and focus hold), the 0.5 mm vanes, and easier collimation with 4 points and Bob's Knobs.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the double-vane design of the RB Focus spider create double diffraction spikes?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. RB Focus says that at focus the patterns from the two vanes cancel out into fine, elongated spikes rather than doubled ones.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 4-point system on the RB Focus spider make collimation easier?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith 4 collimation points, factory-fitted Bob's Knobs and a modified collimation clutch, RB Focus says squaring the focuser and collimating the secondary becomes much easier.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI have a 250mm Sky-Watcher Newtonian. Will the RB Focus spider fit?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThere is a 250 mm version, and the package includes four adapter pieces for Sky-Watcher telescopes. RB Focus does not list specific telescope models, so ask us to confirm the fit for your tube.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the RB Focus spider behave during a long imaging session with falling temperatures?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eRB Focus says the carbon fiber spider is very resistant to temperature changes, so collimation and focus hold as the temperature varies.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the diffraction pattern from the RB Focus spider to help me focus?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. RB Focus says that because the spikes come together into a fine, clean pattern at focus, the pattern helps confirm the telescope is in focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesign\u003c\/td\u003e\n\u003ctd\u003eDouble-vane spider\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterials\u003c\/td\u003e\n\u003ctd\u003e3K carbon fiber, stainless steel, brass and carbon-fiber PLA (FDM printed)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVane width\u003c\/td\u003e\n\u003ctd\u003e0.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVane spacing\u003c\/td\u003e\n\u003ctd\u003e10 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCollimation screws\u003c\/td\u003e\n\u003ctd\u003eBob's Knobs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCollimation points\u003c\/td\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSizes\u003c\/td\u003e\n\u003ctd\u003e150, 200, 250 and 300 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eRB Focus Carbon Fiber Double Spider\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBob's Knobs\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 4\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAdapter pieces for Sky-Watcher telescopes\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 4\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eCollimation clutch\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/rb-focus-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eRB Focus 2-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"RB Focus","offers":[{"title":"150 mm","offer_id":67881971876125,"sku":"RB-SPIDER-150","price":200.99,"currency_code":"USD","in_stock":true},{"title":"200 mm","offer_id":67881971908893,"sku":"RB-SPIDER-200","price":223.99,"currency_code":"USD","in_stock":true},{"title":"250 mm","offer_id":67881971941661,"sku":"RB-SPIDER-250","price":282.99,"currency_code":"USD","in_stock":true},{"title":"300 mm","offer_id":67881971974429,"sku":"RB-SPIDER-300","price":341.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/78d234_0716651570b845c39c177499cc0d1e5c_mv2.png?v=1793070918","url":"https:\/\/davidastro.com\/fr-us\/products\/rb-focus-carbon-fiber-double-vane-spider","provider":"David Astro","version":"1.0","type":"link"}