This Coronado SolarMax II 90 dual-etalon solar telescope is designed to do much more for you than merely show you sunspots, as an ordinary white light solar filter can. Its dual passband Hydrogen-Alpha solar filter reveals features of the Sun that are normally hidden by the fierce glare of this nearest of stars – features that change constantly as you watch. The high resolution 90mm aperture of the SolarMax II 90 reveals small, intricate, and subtle details in the ever-changing tapestry of prominences leaping off the edges of the solar disk, the explosive upheavals of flares on the Sun’s disk, and the subtle mottling of granulation across the face of the Sun.
The Coronado SolarMax II 90 DS Hydrogen-Alpha solar telescope by Meade is “double-stacked,” with two filter etalons for increased contrast of solar disk features. One etalon is internal and uses Coronado’s unique RichView tuning system. The removable second etalon threads onto the front of the scope and is separately tunable using the well-known Coronado T-Max tuning system.
Double-stacking the etalons improves the scope’s already outstanding resolution and contrast by cutting the single etalon model’s narrow <0.7 Ångstrom passband to a very narrow <0.5 Ångstrom. Narrowing the passband improves the contrast and visibility of subtle disk features, although it slightly reduces the brightness of prominences. For maximum prominence brightness, the front etalon of the SolarMax II 90 DS can be removed to let the scope function as a single etalon solar scope providing a <0.7 Ångstrom passband. The30mm clear aperture blocking filter is designed for binoviewing and imaging with large 35mm-format chip size DSLR and CCD cameras in both single and double etalon configurations.
The Coronado SolarMax II 90 solar telescope by Meade starts with a brass and black 800mm focal length 90mm aperture f/8.8 refractor. It has been custom-built to provide high definition Hydrogen-Alpha solar feature views using Coronado’s unique RichView tuning Hydrogen-Alpha solar filter.
The three-piece solar filter consists of a sub-aperture etalon in the body of the scope with a lever-type RichView tuning assembly, a second etalon at the front of the scope with a rotary dial T-Max tuner, and a 30mm clear aperture blocking filter in the scope’s 1.25” star diagonal. The dual-etalon “double-stacked” solar filter has a <0.5 Ångstrom passband, centered on the 6562.8 Ångstrom H-Alpha line. The very narrow passband width gives you higher contrast on disk details than a single etalon system, with only a slight reduction in prominence brightness. The filters are thermally stable, so there is no drifting off the H-Alpha line as the filters heat up during extended use.
The 30mm clear aperture of the blocking filter portion of H-alpha system built into the star diagonal is designed to provide full disk single eyepiece views of the Sun for single eyepiece visual use, binoviewing, and imaging with large 35mm-format size DSLR and CCD cameras. There is also a somewhat more economical 15mm blocking filter version of this scope designed for imagers who do not need quite as wide an illuminated field for use with medium (APS-C) chip size DSLR or CCD cameras.
The new and revolutionary RichView tuning assembly of the Meade Coronado SolarMax II 90 represents a breakthrough in solar observing. This patented system allows very precise direct tuning of the primary filter etalon by a lever in the side of the scope body to shift the filter’s passband off the H-Alpha line. This lets you observe Doppler-shifted solar activity to determine whether Doppler-shifted features, such as flares, are moving towards you or away from you as they leap off the surface of the Sun. No other commercially available H-Alpha telescope can provide the tuning range and accuracy of the SolarMax II 90. Now you can tune for the highest contrast views of active regions, flares, filaments, and other surface detail, or quickly and easily re-tune for prominences on the solar limb.
The SolarMax II 90 has a manual 1.25” drawtube that extends for rough focusing. A helical focusing ring around the drawtube then provides the appropriate final fine focusing. This method provides enough back focus to allow both visual observing and imaging.
A set of Coronado Cemax 1.25” eyepiece is standard equipment, providing magnifications of 32x with a 1.62° field, 44x with a 1.18° field, and 67x with a 0.78° field. You can use most 1.25” eyepieces with the Coronado SolarMax II 90, as well. Any good quality 50° field Plössls will work well, as their contrast is generally good and their fields are wide and flat. For still higher power views, consider adding the Coronado Cemax 2x Barlow to your system. Like the Cemax eyepieces, its performance and coatings are optimized for solar observing.
A hard carrying case is standard equipment to transport and store the 90mm Coronado SolarMax II. A clamshell mounting ring is provided to let you mount the 33” long 26 lb. SolarMax II 90 telescope on a suitably-sturdy astronomical mount by adding an optional dovetail mounting plate. The supplied Coronado Sol Ranger Sun Finder makes it easy to center the Sun’s image in the eyepiece. The Sol Ranger connects to the supplied SolarMax II 90 clamshell scope mounting ring as can be seen in the image above.