{"product_id":"photosphere-7-5nm-1-25-filter-e-series","title":"Photosphere 7.5nm 1.25″ Filter E-series","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Player One Astronomy Photosphere 7.5nm 1.25″ E-series filter isolates a narrow 7.5 nm slice of green light centred on 540 nm to lift the contrast of the Sun's visible surface. Working in this continuum band makes sunspots, faculae, and granulation stand out more crisply than a broadband white-light view, giving your solar images cleaner photospheric structure. It transmits about 97% in-band while blocking out-of-band light to OD4.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis filter is for white-light solar imagers who already view the Sun safely and want more contrast on the photosphere. If you photograph sunspot groups and granulation and want to sharpen that detail, the Photosphere 540 nm continuum filter is made for the job.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e540 nm continuum band:\u003c\/strong\u003e centres on green light where photospheric contrast is high, making sunspots and granulation pop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrow 7.5 nm bandwidth:\u003c\/strong\u003e restricts the passband to a slim window for cleaner, higher-contrast detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e≈97% in-band transmission:\u003c\/strong\u003e keeps the solar surface bright for short, sharp exposures.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOD4 out-of-band blocking:\u003c\/strong\u003e suppresses light outside the passband to preserve contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePV 1\/4λ wavefront:\u003c\/strong\u003e figured to a quarter-wave to protect resolution through the imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ thread (M28.5×0.6):\u003c\/strong\u003e fits standard 1.25-inch cells, drawers, and wheels.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical\/Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Photosphere filter passes a 7.5 nm-wide (FWHM) band centred on 540 nm at about 97% transmittance, while rejecting out-of-band light to optical density 4 (OD4). Restricting the view to this green continuum window raises the visible contrast of photospheric features because sunspot umbrae, penumbrae, and granulation modulate strongly there; narrowing the band trims the surrounding light that would otherwise wash the detail out. The 1.85 mm-thick optical-glass substrate carries a multi-layer composite coating and is figured to a PV 1\/4 wavelength wavefront. Mechanically it uses the 1.25-inch M28.5×0.6 thread with a 5 mm body plus 2.5 mm thread section (7.5 mm total).\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eHigh-contrast white-light imaging of sunspots and granulation.\u003c\/li\u003e\n\u003cli\u003eContinuum-band solar photography where a broadband view looks flat.\u003c\/li\u003e\n\u003cli\u003e1.25-inch solar imaging trains that already include safe aperture-side solar filtration.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility \u0026amp; Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFit:\u003c\/strong\u003e 1.25″ M28.5×0.6 filter thread — works in 1.25-inch cells, drawers, and filter wheels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSolar setup:\u003c\/strong\u003e used within a properly filtered white-light train (for example behind a safe aperture solar film or a Herschel wedge), not on its own.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus:\u003c\/strong\u003e the 7.5 mm cell and 1.85 mm glass add to your optical path; include them in your spacing calculation.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eThis is a contrast-enhancing continuum filter, not a solar safety filter; the Sun must already be made safe to view by an approved aperture or wedge filter ahead of it.\u003c\/li\u003e\n\u003cli\u003ePlayer One does not publish a bandwidth tolerance or a net weight for this filter; the shipping weight shown at checkout is an estimate. Contact us if you need exact figures.\u003c\/li\u003e\n\u003cli\u003eInserting the filter shifts focus slightly, so refocus after fitting it.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eFAQ\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e No. It threads into a standard 1.25-inch cell, drawer, or wheel within your existing safe white-light train and needs no power; refocus once after fitting.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat does a 540 nm photosphere filter do?\u003c\/strong\u003e It confines the view to a narrow green continuum band where photospheric contrast is highest, so sunspots and granulation appear sharper than in a broadband white-light image.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this a solar safety filter?\u003c\/strong\u003e No. It enhances contrast only; a safe aperture or Herschel-wedge solar filter must already be in place to make the Sun safe to view and image.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy the narrow 7.5 nm band?\u003c\/strong\u003e A slim passband trims surrounding light that would otherwise reduce contrast, letting fine surface structure show more clearly.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Photosphere 7.5nm 1.25″ E-series filter sharpens white-light solar detail by isolating a 7.5 nm continuum band at 540 nm with ~97% transmission and OD4 blocking, bringing out sunspots and granulation in your images.\u003c\/p\u003e","brand":"Player One Astronomy","offers":[{"title":"Default Title","offer_id":44013787545711,"sku":"POA-PS125E","price":138.6,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/PS125E-filter-logo__10151.png?v=1766562683","url":"https:\/\/ontariotelescope.com\/products\/photosphere-7-5nm-1-25-filter-e-series","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}