{"id":15337,"date":"2025-07-05T17:44:22","date_gmt":"2025-07-05T15:44:22","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=15337"},"modified":"2026-03-03T20:25:46","modified_gmt":"2026-03-03T19:25:46","slug":"zwo-clear-glass-filter-d21","status":"publish","type":"product","link":"https:\/\/staging.telescoop.nl\/en\/zwo-helderglasfilter-d21\/","title":{"rendered":"ZWO Clear Glass Filter D21"},"content":{"rendered":"<p class=\"wp-block-paragraph\"><strong>ZWO Clear Glass Filter D21<\/strong> is a transparent filter specifically designed to protect the sensor of your ZWO ASI camera from dust, moisture and scratches, without significantly affecting light transmission. With a transmission of 95 %, your image remains clear and contrasty, ideal for both reflecting telescopes and refractors.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Key benefits<\/strong><br>\u2713 <strong>High-transmission glass (95 %)<\/strong> - preservation of sharpness and contrast without color shift<br>\u2713 <strong>Sensor protection<\/strong> - Prevents dust and moisture build-up on the sensor during long sessions<br>\u2713 <strong>Universal fit<\/strong> - directly compatible with ASI D21 cameras (M42 thread)<br>\u2713 <strong>Easy mounting<\/strong> - Screw it before any other filter or corrector for maximum protection<br>\u2713 <strong>Low maintenance<\/strong> - easy to clean with air blower or lens cloth<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Practical application<\/strong><br>Place this clear glass filter as the first element in your filter wheel or directly on the camera to protect your expensive mono or color sensor. When used with reflecting telescopes, you prevent dust and moisture from settling during long exposures. With refractors, this filter will keep UV\/IR-blockers or narrowband filters clean and safe.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Technical specifications<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Format: ASI D21 (M42 x 0.75)<\/li>\n\n\n\n<li>Filter type: Clear glass<\/li>\n\n\n\n<li>Transmission: 95 %<\/li>\n\n\n\n<li>Coating: multi-coated for minimal reflection<\/li>\n\n\n\n<li>Glass thickness: 2 mm<\/li>\n\n\n\n<li>Mounting: threaded<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p data-start=\"1729\" data-end=\"1799\">\u00a0<\/p>\n<p data-start=\"1568\" data-end=\"1727\">ZWO Clear Glass Filter D21 for ASI Cameras. Protect your sensor from dust and moisture with 95 % transmission with no image loss.<\/p>","protected":false},"featured_media":21094,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[123],"product_cat":[56,588],"product_tag":[],"class_list":["post-15337","product","type-product","status-publish","has-post-thumbnail","product_brand-zwo","product_cat-telescoop-accessoires","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":15362,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-ir-blocking-filter-d21\/","url_meta":{"origin":15337,"position":0},"title":"ZWO IR-blocking filter D21","author":"","date":"06-07-2025","format":false,"excerpt":"\u00a0 ZWO IR-blocking filter D21 protects your ASI camera and blocks infrared for razor-sharp, high-contrast shots. 90 % transmission, M42 loose design.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO IR-Sperrfilter D21","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D21.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":15341,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-helderglasfilter-d25\/","url_meta":{"origin":15337,"position":1},"title":"ZWO Clear Glass Filter D25","author":"","date":"05-07-2025","format":false,"excerpt":"\u00a0 ZWO Clear Glass Filter D25 for ASI cameras - 95 % transmission and reliable sensor protection without image loss.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO Klarglasfilter D25","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-Helderglasfilter-ASI-D25.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":15365,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-ir-blocking-filter-d25\/","url_meta":{"origin":15337,"position":2},"title":"ZWO IR-blocking filter D25","author":"","date":"06-07-2025","format":false,"excerpt":"\u00a0 ZWO IR-blocking filter D25 for ASI cameras. Blocks infrared, protects sensor and provides 90 % transmission for razor-sharp, high-contrast images.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO IR-Sperrfilter D25","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Blocking-filters-IR-ASI-D25.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":15334,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-lrgb-filterset-1-25-inch\/","url_meta":{"origin":15337,"position":3},"title":"ZWO LRGB filter set 1.25 inches","author":"","date":"05-07-2025","format":false,"excerpt":"ZWO LRGB filterset 1.25 inch\u00a0voor ASI 1600 MM Mono. Hoge transmissie, UV\/IR-cut L-filter en parafocaal ontwerp voor perfecte kleur-deep-sky en planetaire foto\u2019s.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO LRGB Filtersatz 1,25 Zoll","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-LRGB-filterset-voor-ASI-1600-MM-Mono-1-25-.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":15348,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-lrgb-filterset-36-mm-losse-filters\/","url_meta":{"origin":15337,"position":4},"title":"ZWO LRGB filter set 36 mm separate filters","author":"","date":"06-07-2025","format":false,"excerpt":"\u00a0 ZWO LRGB filter set 36 mm separate filters for ZWO cameras. Four multi-coated interference filters, including UV\/IR-block Luminance filter, for full-resolution color channels.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO LRGB-Filterset 36 mm lose Filter","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Filters-LRGB-Filter-36mm-unmounted.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":15397,"url":"https:\/\/staging.telescoop.nl\/en\/zwo-adapter-nikon-objectieven-op-asi-cameras\/","url_meta":{"origin":15337,"position":5},"title":"ZWO adapter Nikon lenses on ASI cameras","author":"","date":"06-07-2025","format":false,"excerpt":"\u00a0 ZWO adapter for Nikon lenses on ASI cameras. Supports 12.5\/17.5 mm back focus and internal M48 filter thread. Rugged aluminum, quick mounting.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"ZWO Adapter Nikon-Objektive auf ASI-Kameras","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/07\/ZWO-Adapter-Nikon-objectieven-op-ASI-camera-s.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product\/15337","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/comments?post=15337"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/21094"}],"wp:attachment":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=15337"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_brand?post=15337"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_cat?post=15337"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/product_tag?post=15337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}