Coronado SolarMax II 90 mm Ha Telescope with BF30, and Dual Etalons

  • Sale
  • $4,999.00
  • Regular price $6,398.00
  • Coronado SolarMax II 90 mm Ha Telescope with BF30, and Dual Etalons

    • Sale
    • $4,999.00
    • Regular price $6,398.00
    • ITEM #

    • 2 available



    Coronado SolarMax II 90 mm Ha Telescope with BF30, and Dual Etalons

    The SolarMax II 90 mm (3.54-Inch) Aperture, Below 0.5 Angstrom, H-alpha Telescope with a 30 mm Blocking Filter, plus Internal and External Etalons 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 II 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 II 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 II 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, strong-contrast H-alpha 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 0.5 Angstrom 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, when properly cared for, will last a lifetime.

    The dual etalons of the Coronado SolarMax 90 are used to sharpen the filter's normal below 0.7 Angstrom pass band to a very narrow below 0.5 Angstrom centered on the 6562.8 Angstrom Ha line, thus improving contrast over the single etalon version. A complete second 90 mm etalon assembly is mounted in front of the Coronado SolarMax 90's normal full-aperture 90 mm etalon along with a factory-installed and performance-matched second etalon mounted inside the telescope barrel. This etalon combination provides the contrast benefits of double stacking, but offers it at a lower cost. By using factory-matched etalons, you are also added better performance than an additional etalon added at a later time.

    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 0.5 A 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 .025-inch to 20 Thread Tripod Adapter.
    • Solar Max 90 Is Double Stacked!
    OPT Product Number: CI-SMT90DS-30

    Additional Information

    Aperture90 mm (3.54")
    Bandwidth<0.5 A
    Blocking/ERF Aperture30mm
    Emission LineH Alpha
    Focal Ratiof/8.8
    Free ShippingYes
    OTA Length30"
    OTA Weight23 lbs.
    Solar Finder IncludedYes
    Tuner IncludedYes
    Warranty1 Year Warranty

    Questions & Answers

    Ask a Question
    • What is the practical difference between the BF30 and BF15?

      The BF30 is a straight through blocking filter designed primarily for imaging where the diagonal is just a red ERF filter to make the image safe for visual use. For a camera, you remove the diagonal and attach a 1.25" to T thread adapter in its place. T

    • hi. Is it possible to use it with zwo 120mm-s for planetary and lunar imaging ?

      Unfortunately, this will not work with the ZWO cameras for planetary imaging. First, you will need a Starlight Xpress Lodestar-X2 or other SX camera to guide, and there is no guarantee of bright guidestars close enough to a planet or the moon imaged at a