{"product_id":"astronomy-plus-tmb-58-high-definition-planetary-eyepiece","title":"Astronomy Plus TMB 58° High-Definition Planetary Eyepiece","description":"\u003ch1\u003eAstronomy Plus TMB 58° High-Definition Planetary Eyepiece\u003c\/h1\u003e\n\u003carticle class=\"text-token-text-primary w-full focus:outline-none [--shadow-height:45px] has-data-writing-block:pointer-events-none has-data-writing-block:-mt-(--shadow-height) has-data-writing-block:pt-(--shadow-height) [\u0026amp;:has([data-writing-block])\u0026gt;*]:pointer-events-auto scroll-mt-[calc(var(--header-height)+min(200px,max(70px,20svh)))]\" dir=\"auto\" data-turn-id=\"request-WEB:2bc4a553-33f2-4b40-9236-c66927f9011b-1\" data-testid=\"conversation-turn-4\" data-scroll-anchor=\"true\" data-turn=\"assistant\" tabindex=\"-1\"\u003e\n\u003cdiv class=\"text-base my-auto mx-auto pb-10 [--thread-content-margin:--spacing(4)] thread-sm:[--thread-content-margin:--spacing(6)] thread-lg:[--thread-content-margin:--spacing(16)] px-(--thread-content-margin)\"\u003e\n\u003cdiv class=\"[--thread-content-max-width:40rem] thread-lg:[--thread-content-max-width:48rem] mx-auto max-w-(--thread-content-max-width) flex-1 group\/turn-messages focus-visible:outline-hidden relative flex w-full min-w-0 flex-col agent-turn\"\u003e\n\u003cdiv class=\"flex max-w-full flex-col grow\"\u003e\n\u003cdiv class=\"min-h-8 text-message relative flex w-full flex-col items-end gap-2 text-start break-words whitespace-normal [.text-message+\u0026amp;]:mt-1\" data-message-author-role=\"assistant\" data-message-id=\"27bd2954-f050-4abb-899c-929d9e754985\" data-message-model-slug=\"gpt-5\"\u003e\n\u003cdiv class=\"flex w-full flex-col gap-1 empty:hidden first:pt-[1px]\"\u003e\n\u003cdiv class=\"markdown prose dark:prose-invert w-full break-words dark markdown-new-styling\"\u003e\n\u003cp data-start=\"0\" data-end=\"432\"\u003eThe TMB Planetary eyepiece design was developed by optical designer Thomas M. Back (TMB) with the goal of achieving \u003cstrong data-start=\"116\" data-end=\"157\"\u003erefractor-like sharpness and contrast\u003c\/strong\u003e in a compact, affordable package. It’s based on a \u003cstrong data-start=\"208\" data-end=\"249\"\u003emodified orthoscopic\/Plössl principle\u003c\/strong\u003e, optimized to reduce common issues such as internal reflections, ghosting, and lateral color while maintaining excellent edge sharpness across a relatively wide 58° apparent field.\u003c\/p\u003e\n\u003cp data-start=\"434\" data-end=\"768\" data-is-last-node=\"\" data-is-only-node=\"\"\u003eEach eyepiece uses \u003cstrong data-start=\"453\" data-end=\"513\"\u003ehigh-quality glass elements with advanced multi-coatings\u003c\/strong\u003e to maximize light transmission and suppress scatter, resulting in crisp planetary and lunar details. The design also emphasizes \u003cstrong data-start=\"642\" data-end=\"685\"\u003elong eye relief and comfortable viewing\u003c\/strong\u003e, even at short focal lengths—something many traditional high-power eyepieces lack.\u003c\/p\u003e\n\u003ch3 data-start=\"434\" data-end=\"768\"\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eDescription\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eApparent Field of View\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e58° (wide field)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBarrel Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1.25″ standard format\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEye Relief\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e16 mm (long eye relief for comfort)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOptical Coatings\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eFully multi-coated with anti-reflective green film\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAvailable Focal Lengths\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e3.2 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eIn the Box\u003c\/h3\u003e\n\u003cp\u003e1.25'' eyepiece at selected focal length :\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/article\u003e\n\u003cul style=\"direction: ltr;\"\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e3.2mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e4mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e5mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e6mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e7mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e8mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e9mm\u003c\/li\u003e\n\u003cli style=\"font-family: Tahoma,Arial,STHeiti,SimSun; font-size: 14px; color: #000000;\"\u003e10mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eManual \u0026amp; Warranty\u003c\/h3\u003e\n\u003cp\u003eAstronomy Plus Warranty\u003c\/p\u003e","brand":"Astronomy Plus","offers":[{"title":"3.2mm","offer_id":47918205894885,"sku":"AP-TA139-3.2","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"4mm","offer_id":47918205927653,"sku":"AP-TA139-4","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"5mm","offer_id":47918205960421,"sku":"AP-TA139-5","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"6mm","offer_id":47918205993189,"sku":"AP-TA139-6","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"7mm","offer_id":47918206025957,"sku":"AP-TA139-7","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"8mm","offer_id":47918206058725,"sku":"AP-TA139-8","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"9mm","offer_id":47918206091493,"sku":"AP-TA139-9","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"10mm","offer_id":47918206124261,"sku":"AP-TA139-10","price":62.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/Untitled_a86d7016-6144-4be8-8090-209f266290f5.png?v=1777045202","url":"https:\/\/astronomyplus.com\/products\/astronomy-plus-tmb-58-high-definition-planetary-eyepiece","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}