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Open Box Coronado Solarmax II 90mm Solar Scope w/BF15 - UT-12611 - SOLD

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  • $2,199.00
  • Regular price $2,499.00

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  • This is an demo solar telescope in like new condition*


Open Box Coronado Solarmax II 90mm Solar Scope w/BF15 - UT-12611 - SOLD

The SolarMax II 90. A 90 mm (3.54-Inch) Aperture Solar Telescope (f/8.8, Below 0.7 Angstrom bandpass, H-alpha) with a RichView Tuning System and a 15 mm Blocking Filter by Coronado Instruments:

Coronado has developed a series of telescopes as a result of the often asked question, What is the best telescope to use with a Coronado filter? While almost all refractors and most reflecting telescopes can be used with a Coronado filter, no other telescope has been designed with all its optical aberrations and coatings optimized at H-alpha (Ha). Most nighttime telescopes, when used at Ha, will not have the image contrast exhibited by a SolarMax nor the image quality. All of the Coronado scopes, even the PST, have been designed with this one wavelength of light in mind and will increase contrast and give you a darker background for viewing and imaging. 

Why buy a telescope that can only look at one object? The Sun in Ha is the most dynamic object you will ever see while pointing a telescope skywards. Constantly changing and never repeating itself the Sun through a Coronado filter will hold your attention for a lifetime. Coronado telescopes serve to enhance that view for you, your family, and friends. The telescopes provide an easy and portable set up that is always ready right out of the box. For those looking for more aperture we proudly present the SolarMax II 60 dedicated H-alpha telescope. Built to our exacting standards the SolarMax II 90's provides the user a telescope with the same lightweight portability of our SolarMax II 60 but the extra aperture greatly increases the resolution of detail on the surface and on the limb. With over twice the surface area of the SolarMax 60 the difference is obvious.

The SolarMax II 90 is the largest Ha telescope ever to be mass-produced and is in use around the world from private observatories to professional research facilities. Noted for incredibly sharp, contrast-strong Ha views, and stunning detail. Even when viewing with a single eyepiece the sun appears fully animated even revealing hints of curvature, this effect is enhanced when used with bino-viewers. The SolarMax 90 is compatible with most imaging systems and amateur astronomers have produced images that rival those gathered by multi million dollar systems.

This Coronado SolarMax II 90 is a handsome aluminum and black f/8.8 refractor with 800 mm focal length and 90 mm aperture. Its purpose is simple. The Coronado SolarMax 90 less than 0.7A was custom-built to optimize the performance of the SolarMax 90 Hydrogen-alpha solar filter. The SolarMax 90 was intended to do much than just reveal sunspots... it was meant for studying prominences, flares, granulation and more. The achromatic doublet lens designed by Dick Buchroeder utilizes special multi-layer anti-reflection coatings on all air-glass surfaces to optimize anti-ghosting. This is an important feature when observing such a bright target as the Sun. Safety issues include hard vacuum-deposited. non-degenerating coatings. This means not only are you assured your vision is protected but your investment as well. The Coronado SolarMax 90 BF15, when properly cared for, will last a lifetime.

At the heart of the SolarMax 90 Below 0.7A , a two-piece solar filter is formed from a full-aperture 90 mm etalon positioned in front of the objective lens and a 15 mm clear aperture blocking filter incorporated into the diagonal. The solar filter has a less than 0.7 Angstrom pass band, centered on the 6562.8 Angstrom H-alpha line and the sub-Angstrom pass band width gives a perfect balance of prominence and surface features. The assembly is thermally stable at 0.005-degree per degree Centigrade, so there is no drifting off the H-alpha line as the filter heats up during normal observing. The 15 mm clear aperture blocking filter is perfectly matched to the focal length of the telescope to give full disk views of the Sun.

On the outside, the Coronado Solar Max II 90 below 0.7A consists of a manual 1.25-inch drawtube which extends for coarse focusing. A secondary helical focusing ring around the drawtube is then used to provide the appropriate final fine focusing. Both visual observing and afocal imaging, as well as Barlow lenses are able to come to focus using this method and digital photography and binoviewers also experience no problems with focus. Between the the solar filter etalon and the objective lens you'll find the RichView tuner which mechanically tilts the filter's bandpass of the h-alpha line. This allows observance of Doppler-shifted solar activity, such as moving flares!


ConditionOpen Box
Warranty90 Day Covered By OPT


  • Cemax Eyepiece Set and Cemax Barlow Included
  • Threaded, Protective Metal Cover For Primary Lens
  • SolRanger Sun Finder
  • Deluxe Hard Carrying Case*
  • Clam-shell Mounting Rings with .025-inch to 20 Thread Tripod Adapter
  • * The case shows some bowing of the end side and front edge. It is still functional *