{"id":29180,"date":"2025-09-22T10:59:27","date_gmt":"2025-09-22T08:59:27","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=29180"},"modified":"2026-07-20T14:51:03","modified_gmt":"2026-07-20T12:51:03","slug":"optolong-clear-focusing-filter-1-25-inches","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/optolong-clear-focusing-filter-1-25-inch\/","title":{"rendered":"Optolong Clear Focusing Filter 1.25 inches"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>Optolong Clear Focusing Filter 1.25 inch: focus first, then narrowband<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Focusing through a narrowband filter is tricky: the image is dark and stars are barely visible. This bright filter solves that. With 98.5 percent transmission between 420 and 680 nm, you can focus quickly and accurately, and then switch to your narrowband filter for the shot.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Furthermore, this is the ideal filler for the empty position in a filter wheel: it keeps the optical path length the same as your other filters and protects the sensor from dust.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-3 is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\"><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-Clear-Focusing-1-25-.jpg\" alt=\"Optolong Clear Focusing Filter 1.25 inch\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-Clear-Focusing-1-25-1.jpg\" alt=\"Optolong Clear Focusing Filter 1.25 inch\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-Clear-Focusing-1-25-2.jpg\" alt=\"Optolong Clear Focusing Filter 1.25 inch\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-Clear-Focusing-1-25-3.jpg\" alt=\"Optolong Clear Focusing Filter 1.25 inch\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-Clear-Focusing-1-25-4.jpg\" alt=\"Optolong Clear Focusing Filter 1.25 inch\" title=\"\"><\/figure><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Features<\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>98.5% transmission between 420 and 680 nm<\/li><li>Maintain focus consistent with filled filter wheel positions<\/li><li>Acts as a dust cap and protective filter for the sensor<\/li><li>Thin 1.25 inch metal barrel<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compatibility<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Fits the standard 1.25 inch thread (M28.5 x 0.6) in filter wheels, nosepieces, and filter holders.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Specifications<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Type<\/strong><\/td><td>Bright focus filter<\/td><\/tr><tr><td><strong>Transmission<\/strong><\/td><td>98.5 percent (420 to 680 nm)<\/td><\/tr><tr><td><strong>Size<\/strong><\/td><td>1.25 inches (M28.5 x 0.6)<\/td><\/tr><tr><td><strong>Observation goals<\/strong><\/td><td>Focusing, filter wheel filling, sensor protection<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">You can find more accessories for this merk at the <a href=\"\/en\/brands\/optolong\/\">Optolong merk page<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>Optolong Clear Focusing Filter 1.25 inch: clear filter with 98.5 percent transmission (420 to 680 nm) for fast and accurate focusing before switching to a narrowband filter. Also provides protection against dust.<\/p>","protected":false},"featured_media":29193,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[1548],"product_cat":[588],"product_tag":[],"class_list":["post-29180","product","type-product","status-publish","has-post-thumbnail","product_brand-optolong","product_cat-filters","product_shipping_class-licht","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":29165,"url":"https:\/\/www.telescoop.nl\/en\/optolong-sho-filter-kit-1-25-inch\/","url_meta":{"origin":29180,"position":0},"title":"Optolong SHO Filter Kit 1.25 inch","author":"","date":"22-09-2025","format":false,"excerpt":"Optolong SHO filterset 1.25 inch with three narrowband filters: H-alpha 7 nm, OIII 6.5 nm, and SII 6.5 nm. 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For monochrome narrowband photography of emission nebulae, even under light-polluted skies.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"Optolong Filters H-alpha 7nm 1,25\"","src":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/www.telescoop.nl\/wp-content\/uploads\/2025\/09\/Optolong-Filters-H-alpha-7nm-1-25-.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":29150,"url":"https:\/\/www.telescoop.nl\/en\/optolong-sho-filter-kit-7nm-2-inch\/","url_meta":{"origin":29180,"position":2},"title":"Optolong SHO Filter Kit 7nm 2 inch","author":"","date":"22-09-2025","format":false,"excerpt":"Optolong SHO filter set 2 inch with three narrowband filters: H-alpha 7 nm, OIII 6.5 nm, and SII 6.5 nm. 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