• The Coronado SolarMax II 90 Double Stack has a 800mm focal length and an f/8.8 focal ratio.
• Includes 15mm blocking filter.
• Takes solar viewing and imaging many steps further than traditional white light, making solar prominence and other details more within reach!
• The front etalon with the double stack filter has an extremely narrow 0.05nm bandpass (or <0.5 Angstroms) centered on the H-Alpha emission line at 656.28nm.
• The optical design and filters are thermally stable, thus heat does not reduce or affect spectral quality.
• Built with Coronado's RichField tuning.

For observers who want to view the ever and daily changing activity of the Sun, the Coronado's SolarMax II 90 Double Stack provides the steadfast details that are not visible using traditional white light solar filters or telescopes. The solar filter installed on the top with of the optical tube with the double stack etalon filter has an extremely narrow bandpass of <0.5 angstroms (0.05 nanometers) centered on the H-Alpha line 656.28 nanometers, therefore significantly more activity and details become apparent on the Sun's surface as well as sunspot and flare prominence. Better yet, the filter is thermally stable, so a buildup of heat during observation will not affect performance or change the H-alpha bandpass.

This configuration of the SolarMax II 90 Solar Telescope comes with the BF10 10mm blocking filter which is the second equation to the solar telescope. While the initial front filter has a bandpass centered on the H-Alpha line, the blocking filter further removes any other wavelengths with the exception of the H-alpha emission line so the view of the Sun is purely H-Alpha wavelengths where a majority of activity can be seen.

There are other blocking filter sizes that come with this telescope or can be purchased separately. Depending on whether the user is doing visual or imaging, the focal length of the telescope or sensor size of the camera (APS-C vs Full Frame) will depend on the proper blocking filter size that is needed.

With Coronado's patented Richfield Tuning system, the user can adjust tuning of the front etalon filter for either high contrast views such as flares, sunspots etc to a lower prominence tuning. 

Standard 5 year manufacturer warranty from date of purchase.