Coronado SolarMax II 90 mm H-Alpha Telescope with BF30

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Coronado SolarMax II 90 mm H-Alpha Telescope with BF30

The SolarMax II 90, A 90 mm (3.54-Inch) Solar Telescope at f/8.8, below 0.7 Angstrom, H-alpha with a RichView System and a 30 mm Blocking Filter by Coronado:


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. Most broadband coatings, used on such telescopes, will have reduced effectiveness at this wavelength and telescopes 5 Year Coronado Warranty. (particularly reflectors) not specifically designed for Solar viewing, will exhibit unnecessary scattering and spurious light transmission. 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 H-alpha 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 60 dedicated Ha telescope. Built to our exacting standards the SolarMax 90's provides the user a telescope with the same lightweight portability of our SolarMax 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 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, strong-contrast 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 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 0.7 Angstrom was custom-built to optimize the performance of the SolarMax 90 Ha 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 straight-through BF30, when properly cared for, will last a lifetime.

At the heart of the SolarMax 90, a two-piece solar filter is formed from a full-aperture 90 mm etalon positioned in front of the objective lens and a 30 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 Ha line as the filter heats up during normal observing. The 30 mm clear aperture straight-through 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 90 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!


Coronado SolarMax 90 less than 0.7A BF30 Features:

  • 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 0.25-inch to 20 Thread Tripod Adapter.
OPT Product Number: CI-SMT90-30



Aperture90 mm (3.5")
Blocking/ERF Aperture30mm
Emission LineH Alpha
Focal Ratiof/8.8
Free ShippingYes
Optical DesignSolar
OTA Length30"
OTA Weight23 lbs.
Solar Finder IncludedYes
Tuner IncludedYes
Warranty5 Year Warranty


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