Daystar Filters' Calcium QUARK Ca H-Line Eyepiece Solar Filter departs from traditional K-line tuned filers and focuses on the 396.9nm H-line wavelength. This wavelength is closer to the visible spectrum and is therefore easier to see - especially older users who have trouble seeing the K-line. When using the filter for imaging the sun, H-line provides improved quantum efficiency, higher glass transmission, and improved performance from anti-reflection optical coatings. H-line also offers slightly more visible features due to the hydrogen contribution. Views through the filter show the chromosphere, plages/faculae, sun spots, and solar flares in a vibrant violet color with high-contrast.
While there are no OTA aperture limitations, Daystar recommends the use of rear UV/IR cut filters for long-duration solar viewing sessions, or OTAs larger than 80mm (3.1"). For best results, they suggest using refractor-style scopes with focal ratios between f/7-f/30, and you can enjoy full-disk viewing with focal lengths up to 1800mm.
This all-in-one filter design enables the use of nighttime telescopes for solar viewing, and is engineered to eliminate unnecessary components which reduced the size and weight. This streamlined form enables it to simply insert into 1.25" or 2" diagonals and accepts 1.25" eyepieces. The filter is powered via a micro-USB port, and Daystar includes a power cord and an AC adapter to meet the high-power requirements of 5 VDC 1.5A. To enable its use at home and abroad, a set of international outlet plugs is provided with adapters for the US, UK, EU, and Australia.