{"product_id":"lunt-b3400-blocking-filter-b3400s2","title":"Lunt B3400 Blocking Filter (B3400s2)","description":"\u003ch2\u003eLunt B3400 Blocking Filter\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBLOCKING FILTER ARE REQUIRED ON ALL LUNT SOLAR TELESCOPES\u003c\/strong\u003e\u003c\/p\u003e\nThe Lunt B3400 Blocking Filter is best for visual work on telescopes with focal lengths up to 3400 mm, and for imaging work on scopes with focal lengths of up to 1800 mm. The Lunt B3400 Blocking Filter is housed in a 2″ straight-through extension tube with 2″ and T2 connections. Like all Lunt blocking filters, the B3400 houses additional filters. Significantly, this is required for the safety and performance of the solar package. It’s important to realize that Lunt Solar blocking filters contain a unique filter system. Furthermore, we can only warranty safety or performance when one of our blocking filters is paired with a Lunt H-alpha filter or telescope. Lunt Solar Systems currently offers a total of four (4) blocking filter apertures for use with our Etalon systems, and they come in a selection of housing designs so that you can choose the best one for your visual or imaging applications.  Significantly, the Blocking Filter houses additional filters which are required for the safety and performance of the solar package. In addition, Lunt Solar blocking filters contain a unique filter system. Another key point is we can only warranty safety or performance when one of our blocking filters is paired with a Lunt H-alpha filter or telescope.\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhich Blocking Filter to Choose\u003c\/strong\u003e\u003c\/p\u003e\nThe smallest recommended BF for a specific scope allows for the most inexpensive version of the assembly without cutting off the image at the image plain. ie: The image size of the 60mm Lunt Solar Telescope is 4.2mm. The 6mm Blocking Filter provides almost 1mm of area around the Solar disk. A smaller Blocking Filter would cut off the image and would not allow for a full disk view. A smaller Blocking Filter would also cause significant uniformity issues at the edges. A slightly larger (one size up) is always recommended whenever the user intends to do imaging, manual tracking, or requires a larger field of view for increased visual comfort and Solar edge contrast. One size up is the minimum recommended size. Depending on the size of your scope and the type of camera you may want to chose 2 step higher Blocking Filter. The advantage of getting a larger Blocking Filter for imaging use now is that, a) it removes the need to upgrade later should you decide to image later, and b) it provides more wiggle room around the Blocking Filter in Visual mode. (There is more dark space around the Sun when viewing). This also has the advantage of not having to adjust the mount as often when tracking manually. To pick the proper blocking filter for you, take a look at the suggestions listed below for visual use and\/or imaging use. Next, match what you want to do with the focal length of the telescope you will be using for solar work.\n\u003cp data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; text-rendering: optimizelegibility; color: #f15c0f; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: 600; line-height: 1.125; margin: 1.424rem 0px 0px; font-size: 1.802rem; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; text-align: left;\"\u003e \u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; text-rendering: optimizelegibility; color: #f15c0f; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: 600; line-height: 1.125; margin: 1.424rem 0px 0px; font-size: 1.802rem; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; text-align: left;\"\u003e\u003cstrong\u003eFocal Length Suggestions for Visual Use:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; list-style: none; padding: 0px; margin: 1.266rem 0px 0.4rem; color: #494846; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB600 : For visual use on telescopes with focal lengths up to 600 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB1200: For visual use on telescopes with focal lengths up to 1200 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB1800: For visual use on telescopes with focal lengths up to 1800 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB3400: For visual use on telescopes with focal lengths up to 3400 mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; text-rendering: optimizelegibility; color: #f15c0f; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: 600; line-height: 1.125; margin: 1.424rem 0px 0px; font-size: 1.802rem; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; text-align: left;\"\u003eFocal Length Suggestions for Imaging Use:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; font-size: 16px; font-weight: 400; line-height: 1.5; margin: 0.8rem 0px 0.2rem; color: #494846; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003eWhen imaging with a Lunt Solar System it is recommended that the user opt for the next larger blocking filter than that recommended for visual use. This is due to the fact that most imaging systems require additional “back focus”.  It’s important to realize that the blocking filter be moved further up the light cone. As a result, the aperture of the blocking filter needs to be larger to allow for the larger cone size.\u003c\/p\u003e\n\u003cul data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; list-style: none; padding: 0px; margin: 1.266rem 0px 0.4rem; color: #494846; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB600: For imaging use on telescopes with focal lengths up to 400 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB1200: For imaging use on telescopes with focal lengths up to 600 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB1800: For imaging use on telescopes with focal lengths up to 1200 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003eB3400: For imaging use on telescopes with focal lengths up to 1800 mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; text-rendering: optimizelegibility; color: #f15c0f; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-weight: 600; line-height: 1.125; margin: 1.424rem 0px 0px; font-size: 1.802rem; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; text-align: left;\"\u003e\u003cstrong\u003eLunt Solar Blocking Filter Housing Options\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; list-style: none; padding: 0px; margin: 1.266rem 0px 0.4rem; color: #494846; font-family: Silka, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003e1.25″ or 2″ diagonal with T2 connection\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" data-mce-style=\"background-repeat: no-repeat; box-sizing: border-box; overflow: visible; padding: 0px; font-size: 1rem; line-height: 1.5; margin: 0.5rem 0px 0.5rem 1rem; list-style: none; position: relative;\"\u003e2″ extension tube with T2 and 2″ connection, aka “straight-through”\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 data-mce-fragment=\"1\"\u003eIn the Box\u003c\/h3\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\u003c\/ul\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003e\n\u003cp data-mce-fragment=\"1\"\u003eLunt B3400 Blocking Filter 2\" Straight-Through\u003cbr data-mce-fragment=\"1\"\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\u003c\/ul\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\u003c\/ul\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\u003c\/ul\u003e\n\u003ch3 data-mce-fragment=\"1\"\u003eWarranty \u0026amp; Manuals\u003cbr data-mce-fragment=\"1\"\u003e\n\u003c\/h3\u003e\n\u003cp data-mce-fragment=\"1\"\u003eLunt 5-Year Warranty\u003c\/p\u003e\n\u003ch3\u003e\u003c\/h3\u003e","brand":"Lunt","offers":[{"title":"Default Title","offer_id":43125688729829,"sku":"LS-3400s2","price":3493.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/lunt-b3400-blocking-filter-b3400s2-astronomy-plus.webp?v=1690483742","url":"https:\/\/istronomyplus.com\/products\/lunt-b3400-blocking-filter-b3400s2","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}