{"id":112907,"date":"2026-10-09T16:52:47","date_gmt":"2026-10-09T14:52:47","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=112907"},"modified":"2026-10-09T20:32:20","modified_gmt":"2026-10-09T18:32:20","slug":"adjustment-screws-for-the-catch-mirror-of-a-6-inch-sct-bobs-knob","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/afstelschroeven-voor-de-vangspiegel-van-een-6-inch-sct-bobs-knobs\/","title":{"rendered":"Adjustment screws for the rear mirror of a 6 inch SCT | Bob\u2019s Knobs"},"content":{"rendered":"

A 6-inch Schmidt-Cassegrain is compact and easy to carry, but the small collimation screws on the secondary holder are difficult to operate, especially with gloves on. These adjustment screws for a 6-inch SCT from Bob\u2019s Knobs replace them with larger knobs that you twist with your fingers.<\/p>\n\n\n\n

First, check that your telescope is a 6-inch Schmidt-Cassegrain with the usual collimation screws on the secondary holder. This type of viewer can be found in the catadioptric telescopes<\/a>.<\/p>\n\n\n\n

Replace the screws one by one so that the mirror remains in place. Then adjust the collimation to a bright star at high magnification, or with a artificial star for collimation<\/a>, with increasingly small turns.<\/p>\n\n\n\n

If you have a Celestron C6 f\/10 with metric thread, there is a set specially designed for the C6<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"

Large adjustment buttons from Bob\u2019s Knobs for the secondary mirror of a 6 inch SCT, for collimation by hand.<\/p>","protected":false},"featured_media":112906,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[1559],"product_cat":[56,3091],"product_tag":[],"class_list":["post-112907","product","type-product","status-publish","has-post-thumbnail","product_brand-bobs-knobs","product_cat-telescoop-accessoires","product_cat-telescoop-onderdelen","first","instock","taxable","shipping-taxable","purchasable","product-type-simple"],"bundled_by":[],"bundle_stock_status":"instock","bundle_stock_quantity":null,"bundle_virtual":false,"bundle_layout":"","bundle_add_to_cart_form_location":"","bundle_editable_in_cart":false,"bundle_sold_individually_context":"","bundle_item_grouping":"","bundle_min_size":"","bundle_max_size":"","bundle_price":[],"bundled_items":[],"bundle_sell_ids":[],"acf":[],"jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":30398,"url":"https:\/\/www.telescoop.nl\/en\/bobs-knobs-afstelschroeven-voor-celestron-sct-11-f-10-metric\/","url_meta":{"origin":112907,"position":0},"title":"Bob's Knobs Adjusting Screws for Celestron SCT 11\u2033 f\/10 Metric","author":"","date":"08-10-2025","format":false,"excerpt":"Bob's Knobs for the Celestron 11-inch f\/10 SCT Metric: stainless steel thumb screws for secure, tool-free secondary mirror collimation.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"Bob\u2019s Knobs Afstelschroeven voor Celestron SCT 11\" f\/10 Metric","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-11-f-10-metric.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-11-f-10-metric.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-11-f-10-metric.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-11-f-10-metric.jpg?resize=700%2C400&ssl=1 2x, 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SCT","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/10\/Bobs-Knobs-SCT-8-post-1980-Standard-.jpg?resize=1400%2C800&ssl=1 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secondary holder. This way you can line up without a screwdriver.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/58067_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/58067_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/58067_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112912,"url":"https:\/\/www.telescoop.nl\/en\/afstelschroeven-voor-de-vangspiegel-van-een-5-inch-sct-f-6-bobs-knobs\/","url_meta":{"origin":112907,"position":4},"title":"Adjusting screws for the viewfinder of a 5 inch SCT f\/6 | Bob\u2019s Knobs","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"Adjustment knobs from Bob's Knobs for the secondary mirror of a 5 inch Schmidt-Cassegrain with f\/6.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87171_1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87171_1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2026\/10\/87171_1.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":112863,"url":"https:\/\/www.telescoop.nl\/en\/afstelschroeven-voor-de-vangspiegel-van-een-5-inch-sct-f-10-metrische-draad-bobs-knobs\/","url_meta":{"origin":112907,"position":5},"title":"Adjusting screws for the viewfinder of a 5 inch SCT f\/10, metric thread | Bob\u2019s Knobs","author":"Info telescoop","date":"09-10-2026","format":false,"excerpt":"Bob's Knobs with metric thread for the viewfinder of a 5 inch Schmidt-Cassegrain f\/10 telescope. 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