{"product_id":"lunt-double-stack-etalon-filter-for-mt-telescopes","title":"Lunt Double Stack Etalon Filter for MT Telescopes","description":"\u003cdiv class=\"kt-page\"\u003e\n\n\u003cstyle\u003e\n.kt-page{--kt-primary:#030B1C;--kt-accent:#2E7FBF;max-width:1100px;margin:0 auto;font-family:inherit;}\n.kt-page.kt-page--wide{max-width:1600px;}\n.kt-page .kt-hero{display:flex;align-items:center;gap:40px;margin-bottom:40px;}\n.kt-page .kt-hero-copy{flex:1 1 55%;}\n.kt-page .kt-hero-img{flex:1 1 40%;text-align:center;}\n.kt-page .kt-sq{width:100%;max-width:420px;aspect-ratio:1\/1;margin:0 auto;background:#ffffff;border-radius:6px;display:flex;align-items:center;justify-content:center;overflow:hidden;}\n.kt-page .kt-sq img{max-width:92%;max-height:92%;width:auto;height:auto;object-fit:contain;}\n.kt-page .kt-hero-copy h2{font-size:26px;margin-bottom:14px;}\n.kt-page .kt-hero-copy p{font-size:16px;line-height:1.6;margin-bottom:14px;}\n.kt-page .kt-features{display:flex;align-items:flex-start;gap:40px;margin:40px 0;}\n.kt-page .kt-features-copy{flex:1 1 55%;}\n.kt-page .kt-features-img{flex:1 1 40%;text-align:center;}\n.kt-page .kt-section-heading{font-size:21px;display:inline-block;padding-bottom:8px;border-bottom:2px solid var(--kt-accent);margin-bottom:18px;}\n.kt-page .kt-feature-list{list-style:none;margin:0;padding:0;}\n.kt-page .kt-feature-list li{font-size:16px;line-height:1.5;margin-bottom:12px;padding-left:26px;position:relative;}\n.kt-page .kt-feature-list li:before{content:\"\\2713\";color:var(--kt-accent);font-weight:bold;position:absolute;left:0;}\n.kt-page .kt-feature-list b{color:#222;}\n.kt-page .kt-specs-wrap{box-sizing:border-box;}\n.kt-page .kt-specs{display:table !important;width:100% !important;border-collapse:collapse;margin:40px 0;font-size:15px;}\n.kt-page .kt-specs th,.kt-page .kt-specs td{border:2px solid #000;padding:10px 12px;text-align:left;}\n.kt-page .kt-specs th{background:var(--kt-primary) !important;color:#fff !important;font-size:16px;}\n.kt-page .kt-specs tr:nth-child(even){background:#f2f2f2;}\n.kt-page .kt-specs tr:nth-child(odd){background:#ffffff;}\n.kt-page .kt-cta{text-align:center;margin:40px 0;font-size:18px;font-weight:bold;}\n.kt-page .kt-cta-buttons{display:flex;justify-content:center;gap:16px;margin-top:16px;flex-wrap:wrap;}\n.kt-page .kt-cta-buttons a{display:inline-block;padding:12px 26px;border:2px solid var(--kt-primary);border-radius:4px;color:var(--kt-primary);text-decoration:none;font-weight:bold;font-size:15px;transition:all .15s ease;}\n.kt-page .kt-cta-buttons a:hover{background:var(--kt-primary);color:#fff;}\n.kt-page .kt-manuals a{display:block;color:var(--kt-primary);font-weight:bold;font-size:30px;text-align:left;text-decoration:none;margin-bottom:10px;}\n.kt-page .kt-manuals a:hover{color:var(--kt-accent);}\n@media (max-width:768px){\n  .kt-page .kt-hero,.kt-page .kt-features{flex-direction:column;}\n  .kt-page .kt-hero-img img,.kt-page .kt-features-img img{max-width:400px;}\n  .kt-page .kt-hero-copy p,.kt-page .kt-features-copy p{font-size:17px;}\n  .kt-page .kt-cta-buttons{display:grid;grid-template-columns:1fr 1fr;gap:12px;}\n  .kt-page .kt-cta-buttons a:nth-child(3){grid-column:1 \/ span 2;}\n  .kt-page .kt-manuals a{font-size:24px;}\n}\n\u003c\/style\u003e\n\n\u003cdiv class=\"kt-hero\"\u003e\n  \u003cdiv class=\"kt-hero-copy\"\u003e\n    \u003ch2\u003eNarrow The Bandwidth On Your MT Telescope\u003c\/h2\u003e\n        \u003cp\u003eA double stack etalon puts a second filter in series with the etalon already in your Lunt MT telescope. Single stack gives you 0.7 Angstrom or better. Adding the second etalon takes the system to 0.5 Angstrom or better, and Lunt reports tighter figures near 0.28 Angstrom on current internal modules. Contrast on the disk climbs sharply.\u003c\/p\u003e\n    \u003cp\u003eChoose the version that matches your telescope. The LS50FHaP and LS60FHa front mount on the LS60MT and LS60THa. The internal SFPT module drops inside the LS80MT and LS100MT. The LS130MTP module serves the LS130MT. The LS100FHa front mount covers the LS100MT and LS100THa. Each one leaves the night sky configuration untouched.\u003c\/p\u003e\n    \u003cp\u003eAt the narrower bandwidth you see filaments resolve into dark cores and multiple strands, plage boundaries sharpen into cellular networks, and active regions show more magnetic structure. The trade is brightness, so plan on lower magnification or longer exposures. Pressure tuning shifts the passband on and off band without tilting the etalon, and the internal modules install without a factory return.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"kt-hero-img\"\u003e\n    \u003cdiv class=\"kt-sq\"\u003e\n      \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0615\/8273\/7521\/files\/DS2-80-Double-Stack-Filter-Lunt-Solar-Telescope.jpg?v=1743113214\" alt=\"Lunt SFPT internal double stack etalon module for the LS80MT and LS100MT universal telescopes\"\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"kt-features\"\u003e\n  \u003cdiv class=\"kt-features-copy\"\u003e\n    \u003ch3 class=\"kt-section-heading\"\u003eKey Features\u003c\/h3\u003e\n    \u003cul class=\"kt-feature-list\"\u003e\n      \u003cli\u003e\n\u003cb\u003eSecond Etalon In Series\u003c\/b\u003e - stacks a second precision etalon with the one already in your telescope to cut the combined bandwidth.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cb\u003e0.5 Angstrom Or Better\u003c\/b\u003e - takes a 0.7 Angstrom single stack system down to 0.5 Angstrom or better, with Lunt quoting under 0.28 Angstrom for the current internal modules.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cb\u003eFront Mount Or Internal\u003c\/b\u003e - arrives as a front mounted filter for 60mm and 100mm class systems, or as an internal module for the 80mm, 100mm and 130mm tubes.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cb\u003eDoppler True Pressure Tuning\u003c\/b\u003e - shifts the passband on and off band without tilting the etalon, and the internal SFPT adds a second independent tuning knob.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cb\u003eCustomer Installed\u003c\/b\u003e - fits without a factory return, so the double stack can be added at purchase or at any point afterward.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cb\u003eNight Sky Unaffected\u003c\/b\u003e - leaves the telescope in its night configuration once the solar module comes out for deep sky use.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"kt-features-img\"\u003e\n    \u003cdiv class=\"kt-sq\"\u003e\n      \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0615\/8273\/7521\/files\/Double-Stack-Filter-60F-Lunt-Solar-Telescope.jpg?v=1743112794\" alt=\"Lunt LS60FHa 60mm front mounted double stack hydrogen alpha filter fitted to a Lunt solar telescope\"\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"kt-specs-wrap\"\u003e\n\u003ctable class=\"kt-specs\"\u003e\n  \u003ctr\u003e\u003cth colspan=\"2\"\u003eSpecifications\u003c\/th\u003e\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eModel \/ SKU\u003c\/td\u003e\n\u003ctd\u003eLS50FHaP, LS60FHa, DSII\/SFPTP, DSII\/LS130MTP, LS100FHa\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003edouble stack hydrogen alpha etalon filter for Lunt MT and THa telescopes\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eLS50FHaP 50mm\u003c\/td\u003e\n\u003ctd\u003efront mounted 50mm etalon, fits the LS60MT and LS60THa\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eLS60FHa 60mm\u003c\/td\u003e\n\u003ctd\u003efront mounted 60mm etalon, fits the LS60MT and LS60THa\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eDSII\/SFPTP Internal\u003c\/td\u003e\n\u003ctd\u003esmall format internal module, fits the LS80MT and LS100MT\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eDSII\/LS130MTP Internal\u003c\/td\u003e\n\u003ctd\u003einternal module, fits the LS130MT\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eLS100FHa 100mm\u003c\/td\u003e\n\u003ctd\u003efront mounted 100mm etalon, fits the LS100MT and LS100THa\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e50mm, 60mm or 100mm on the front mounted versions with no central obstruction, matched to the host telescope on the internal modules\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e0.5 Angstrom or better combined, with Lunt publishing under 0.28 Angstrom for the current SFPT and LS130 internal modules\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eSingle Etalon Bandpass\u003c\/td\u003e\n\u003ctd\u003e0.4 Angstrom on the LS50FHa, LS60FHa, SFPT and LS130 modules as published by Lunt\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eTuning\u003c\/td\u003e\n\u003ctd\u003eLunt Pressure Tuning on the internal modules with dual independent knobs on the SFPT, tilt tuning on the front mounted etalons\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eBlocking Filter\u003c\/td\u003e\n\u003ctd\u003erequired at all times, sold separately\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eMounting\u003c\/td\u003e\n\u003ctd\u003ethreads or clamps to the front cell on the front mounted versions, installs inside the optical path on the internal modules\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003eLS50FHa 10 lb shipping, LS60FHa 11 lb shipping, SFPT module 7 lb shipping, LS130 module 7 lb shipping, LS100FHa Not published\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eWhat's Included\u003c\/td\u003e\n\u003ctd\u003eetalon filter assembly and aluminium hard case with fitted foam on the front mounted versions\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e5 years from date of purchase against manufacturing and workmanship defects\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\n\n\n\u003cp class=\"kt-cta\"\u003e\n  Talk to a Specialist\n  \u003cspan class=\"kt-cta-buttons\"\u003e\n    \u003ca href=\"\/pages\/contact\" style=\"display:inline-block;padding:12px 26px;border:2px solid var(--kt-primary);border-radius:4px;color:var(--kt-primary);text-decoration:none;font-weight:bold;\"\u003eContact Us\u003c\/a\u003e\n    \u003ca href=\"mailto:sales@telescopedepot.com\" style=\"display:inline-block;padding:12px 26px;border:2px solid var(--kt-primary);border-radius:4px;color:var(--kt-primary);text-decoration:none;font-weight:bold;\"\u003eEmail a Specialist\u003c\/a\u003e\n    \u003ca href=\"\/pages\/shipping\" style=\"display:inline-block;padding:12px 26px;border:2px solid var(--kt-primary);border-radius:4px;color:var(--kt-primary);text-decoration:none;font-weight:bold;\"\u003eShipping Info\u003c\/a\u003e\n  \u003c\/span\u003e\n\u003c\/p\u003e\n\n\u003c\/div\u003e","brand":"Lunt Solar Systems","offers":[{"title":"LS50FHaP 50mm (LS60MT, LS60THa)","offer_id":53917549822063,"sku":"LS50FHaP","price":1145.99,"currency_code":"USD","in_stock":true},{"title":"LS60FHa 60mm (LS60MT, LS60THa)","offer_id":53917549854831,"sku":"LS60FHa","price":1495.99,"currency_code":"USD","in_stock":true},{"title":"DSII\/SFPTP Internal (LS80MT, LS100MT)","offer_id":53917549887599,"sku":"DSII\/SFPTP","price":1495.99,"currency_code":"USD","in_stock":true},{"title":"DSII\/LS130MTP Internal Module (LS130MT)","offer_id":53917549920367,"sku":"DSII\/LS130MTP","price":2995.99,"currency_code":"USD","in_stock":true},{"title":"LS100FHa 100mm (LS100MT, LS100THa)","offer_id":53917549953135,"sku":"LS100FHa","price":4495.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0717\/7968\/0367\/files\/DS2-80-Double-Stack-Filter-Lunt-Solar-Telescope.jpg?v=1785527455","url":"https:\/\/telescopedepot.com\/products\/lunt-double-stack-etalon-filter-for-mt-telescopes","provider":"Telescope Depot","version":"1.0","type":"link"}