{"id":50522,"date":"2026-03-08T00:23:18","date_gmt":"2026-03-07T23:23:18","guid":{"rendered":"https:\/\/kart.no\/produkt\/astra-iiib-sight-tube-clear-tube-sight-tube-for-sextant\/"},"modified":"2026-03-08T00:23:18","modified_gmt":"2026-03-07T23:23:18","slug":"astra-iiib-sight-tube-clear-tube-sight-tube-for-sextant","status":"publish","type":"product","link":"https:\/\/kart.no\/en\/produkt\/astra-iiib-sight-tube-clear-tube-sight-tube-for-sextant\/","title":{"rendered":"Astra IIIB Sight Tube (Clear Tube) &#8211; Sight tube for sextant"},"content":{"rendered":"<p data-start=\"84\" data-end=\"338\"><strong data-start=\"84\" data-end=\"122\">Astra IIIB Sight Tube (Clear Tube)<\/strong> is a simple sight tube used instead of a telescope on a <strong data-start=\"184\" data-end=\"196\">sextant<\/strong> for <strong data-start=\"201\" data-end=\"227\">astronomical navigation<\/strong>. The accessory provides a wide field of view and can make it easier to find and follow celestial bodies during observations. <\/p>\n<p data-start=\"340\" data-end=\"652\">A sighting tube &#8211; often called a <em data-start=\"364\" data-end=\"376\">clear tube<\/em> &#8211; is used when optical magnification is not necessary, but where a <strong data-start=\"441\" data-end=\"460\">larger field of view<\/strong> is an advantage. For example, this could be when measuring horizontal angles between objects, or when first locating the sun, moon or a star before possibly using a telescope. <\/p>\n<p data-start=\"654\" data-end=\"1015\">The wide aperture provides a significantly larger field of view than a conventional sextant telescope. This makes it easier to keep the celestial body in the field of view when the sextant is moving, which can be useful when <strong data-start=\"852\" data-end=\"879\">navigating with a sextant<\/strong> in waves or rough seas. Many navigators also use the sighting tube to more quickly locate celestial bodies for more precise observations.  <\/p>\n<p data-start=\"1017\" data-end=\"1246\">The Sight Tube has been developed for <strong data-start=\"1044\" data-end=\"1080\">the Celestaire Astra IIIB sextant<\/strong>, but is also suitable for several other modern metal sextants with a standard telescopic mount, including <strong data-start=\"1179\" data-end=\"1205\">Astra III Professional<\/strong> and some models from Cassens &amp; Plath.<\/p>\n<p data-start=\"1248\" data-end=\"1448\">This is a practical accessory for navigators who want a simple alternative to a telescope when <strong data-start=\"1343\" data-end=\"1367\">sextant sailing<\/strong>, or who want to make it easier to find celestial bodies during observations.<\/p>\n<p data-start=\"1450\" data-end=\"1646\"><strong data-start=\"1450\" data-end=\"1484\">Navigasjonsbutikken Kart.no AS<\/strong> is a distributor of Celestaire in Norway. For schools, courses and institutions, we can also deliver larger batches of sextants &#8211; please contact us for price and delivery time. <\/p>\n","protected":false},"excerpt":{"rendered":"<p data-start=\"316\" data-end=\"529\">Astra IIIB Sight Tube is a sextant sight tube that provides a wide field of view for astronomical navigation.<\/p>\n","protected":false},"featured_media":42039,"comment_status":"open","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":""},"product_brand":[1380],"product_cat":[1101],"product_tag":[],"class_list":{"0":"post-50522","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_brand-celestaire","7":"product_cat-accessories-for-sextants","8":"product_shipping_class-boxship","10":"first","11":"instock","12":"taxable","13":"shipping-taxable","14":"purchasable","15":"product-type-simple"},"composite_virtual":false,"composite_layout":"","composite_add_to_cart_form_location":"","composite_editable_in_cart":false,"composite_sold_individually_context":"","composite_shop_price_calc":"","composite_components":[],"composite_scenarios":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.4 (Yoast SEO v27.4) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Astra IIIB Sight Tube sight tube for sextant<\/title>\n<meta name=\"description\" content=\"Astra IIIB Sight Tube (Clear Tube) sight tube for sextant. 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