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Ideal for those who do not want to have to choose what part of the sun they can optimally view, the Daystar Filters QUARK Gemini H-Alpha Switchable Chromosphere/Prominence Eyepiece Solar Filter is unique in its ability to view both the chromosphere and prominences.
The sun's chromosphere (surface) structure behaves differently in active regions than quiet areas, where magnetic field lines are stronger, so viewing this portion of the sun provides a constantly changing observational experience. By contrast, prominences—details of the chromosphere projected against the blackness of space behind the sun—are seen with improved contrast. Since the bandpass requirements to view these separate features are different, two different etalons are required, so Daystar uses a push-pull etalon changer system that allows you to quickly and easily choose and change the filter without having to remove or power down the entire unit.
This all-in-one hydrogen-alpha filter is engineered to eliminate unnecessary components, which reduces the size and weight and enables it to fit in a compact form factor that simply inserts into 1.25" or 2" diagonals and accepts 1.25" eyepieces. This design enables the use of nighttime telescopes for solar viewing. In addition to the tunable H-alpha filter, the QUARK Gemini also functions as a 4.2x Barlow lens, with a 2-element lens system designed to be telecentric, which flattens the field of view and reduces parallax, and optical coatings that are optimized for the 656nm H-alpha wavelength.
While there are no OTA aperture limitations, Daystar recommends the use of UV/IR cut filters or front-mount energy rejection filters on OTAs over 80mm for long-duration solar viewing sessions. For best results, they suggest using refractor-style scopes with focal ratios between f/4 and f/8, and you can enjoy full-disk viewing with focal lengths up to 450mm.
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.
- Separate individual Fabry Perot etalons allow a single unit to view both prominences and the sun's chromosphere (surface)
- Change etalon using a simple slider, no need to change gear or refocus OTA
- <0.5Å bandpass etalon is used for viewing the chromosphere
- >0.6Å bandpass etalon is for viewing prominences
- 656nm hydrogen-alpha filter
- Integrated 12mm blocking filter
- 22mm clear filter aperture
- Tuning knobs allow for ±0.5Å wing shift for Doppler-shift compensation
- Markers at every 0.1Å for reference and repeatability
- LED indicators for power, warming, ready, and fault
- Integrated 4.2x Barlow lens
- Lens and optical coatings designed specifically for 656nm H-alpha wavelength
- Two-element telecentric lens design keeps light waves parallel to flatten the field of view and reduce parallax as magnification increases
- Fits into both 1.25" and 2" focusers, drawtubes, and accessories like diagonals
- Standard 1.25" holder with brass compression ring to protect eyepiece
- Optional 2" and SCT adapters available separately
- No aperture limitation
- Best performance with f/4-f/8 refractors
- Full-disk viewing on refractors up to 450mm focal length
- For apertures over 80mm (3.1"), or for long-duration solar viewing, an UV/IR cut filter should be used for energy rejection
- Not suited for off-axis applications
- 5 VDC, 1.5A micro-USB port
- 90-240 VAC wall adapter
- Set of international outlet plugs for US, UK, EU, and Australia