The SolarMax II 90 Double Stack Telescope from Coronado features the RichView tuning method which allows direct adjustment of the primary etalon filter. With RichView, the scope can be tuned for more precise wavelengths of light of the hydrogen-alpha (Ha) band. This allows for higher contrast views of active regions, flares, filaments and other surface features. It can be quickly re-tuned for prominences on the solar limb.
The SolarMax II 90 Double Stack is a dedicated H-Alpha solar viewing telescope with a 90mm SolarMax filter, a T-Max 90 tuner, a BF-30 blocking filter, and a set of Cemax eyepieces. The 90mm aperture is double stacked with one internal etalon filter and one external etalon filter at a bandwidth of <0.5 Å. The double stacked SolarMax II filter system delivers superb contrast and detailed resolution. By combining two SolarMax II filters, fine-tuned individually with the RichView tuning system, the bandwidth is reduced from <0.7Å to <0.5Å. The effect of the narrower bandpass is greatly increased contrast on the surface of the Sun, bringing out details in active regions, filaments, flares and other surface phenomenon. The telescope can be used without the external etalon filter attached thereby increasing the bandwidth to <0.7 Å.
The heart of the SolarMax II 90 Double Stack's viewing system is the SolarMax 90 filter and it's matching T-Max 90 Doppler Tuning Unit. This combination can be selectively adjusted by the viewer to de-tune the telescope's optical system. The wavelengths produced by high-velocity events such as active flares and coronal mass ejections (CME) can Doppler-shift and become invisible to a fixed H-Alpha system. The slight adjustment range made possible by the T-Max 90 allows these phenomena to become more visible.
All SolarMax filters must be used with a secondary interference filter. This package includes the BF-30 blocking filter - a 1.25" straight through type that produces a 27.2mm image. The BF-30 is thermally stable, so the image will not drift off the H-Alpha line as it heats up during use. Its 10mm aperture is matched to the telescope's focal length for full disk views of the Sun. This large aperture also enables the use of most Barlow lenses - this simplifies digital photography and enables the use of binoviewers.
SolarMax telescopes produce outstanding views of the Sun's active surface with 100% safety. None of the parts in this kit are stand-alone units - each component is equally crucial to the user's safety and the system's performance.