Coronado SolarMax II 90 <0.5A H-Alpha Telescope with BF15, Internal & External Etalon

More Views

Coronado SolarMax II 90 <0.5A H-Alpha Telescope with BF15, Internal & External Etalon
Item # CI-SMT90DS-15
  • Special multi-layer anti reflection coatings on all air-glass surfaces to optimize anti-ghosting are all part and parcel of the Coronado SolarMax II 90.
  • RichView etalon tuning system and 15mm blocking filter help to provide incredibly sharp, contrasty H-Alpha views, and stunning detail.
  • The Coronado SolarMax II 90 has a sub-ngstrom passband width of <0.5A - providing you with an ideal balance of prominence and surface detail.
  • Package includes Cemax eyepiece set, hard travel case, Sol Ranger, clamshell mounting rings and five year warranty.


Coronado SolarMax II 90 <0.5A Dedicated H-Alpha Solar Telescope

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 optimised at H-Alpha. Most nighttime telescopes, when used at H-alpha, 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 telescopesYear 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-A 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 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 H-A telescope ever to be mass-produced and is in use around the world from private observatories to professional research facilities. Noted for incredibly sharp, ‘contrasty’ 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 II 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 800mm focal length and 90mm aperture. Its purpose is simple. The Coronado SolarMax 90 <0.5A 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 antireflection 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 II 90 are used to sharpen the filter's normal <0.7 Ångstrom passband to a very narrow <0.5 Ångstrom centered on the 6562.8 Ångstrom H-Alpha line, thus improving contrast over the single etalon version. A complete second 90mm etalon assembly is mounted in front of the Coronado SolarMax 90's normal full-aperture 90mm etalon along witha 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 additonal etalon added at a later time.

On the outside, the Coronado Solar Max II 90 <0.5A consists of a manual 1.25" 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 II 90 <0.5A Features...

  • Cemax Eyepiece Set and Cemax Barlow Included!
  • Threaded, Protective Metal Cover For Primary Lens.
  • SolRanger Sun Finder.
  • Deluxe Hard Carrying Case.
  • Clamshell Mounting Rings w/1/4"-20 Thread Tripod Adapter.
  • Solar Max II 90 Is "Double Stacked"!
Coronado Instruments Product Number: SMT90DS-15
Additional Information

Additional Information

UPC Code 709942996326
Solar Instrument Type Telescope
Aperture 81mm - 99mm
Emission Line H-Alpha
Manufacturer Coronado
Warranty 1 Year Warranty
Blocking or ERF Aperture 15mm
Bandwidth <0.5 A
Telescope Focal Length 800mm
Telescope Focal Ratio f/8.8
Solar Finder Included? Yes
Tuner Included? Yes
Length of Optical Tube Not provided by manufacturer
Optical Tube Weight Not provided by manufacturer

Customer Reviews 1 item(s)

One True Light
The MaxScope 90 is a really beautiful work of art. The build of the scope is like nothing I have ever seen before in any scope. Its body appears to be machined from a solid piece of aluminum. For a 90mm it weighs in around 20 pounds. The accessories are also top notch. A full set of Cemax eyepieces and a Cemax barlow come inside the case which holds the scope.

The view simply cannot be described accurately with words. You simply see everything and have the ability to zoom in to the smallest detail. It's imaging ability is also excellent. They put alot into the design because it images as well with a DSLR as it does with a webcam. The supplied BF15 provides all the punch needed to capture breath taking images.

About the only down side to the scope is the focusing. It comes with an odd helical focuser. While this is great for viewing, it is difficult to work with a camera attached. This is the only down side to the scope that I could find. In all other respects it is simply the best.
1= Houston, We Have a Problem & 5= It's Out of This World
Review by Larry Alvarez / (Posted on 8/28/2007)
Included Items

Included Items

  • SolarMax II 90 <0.5A Telescope with Internal & External Etalon
  • 15mm Blocking Filter
  • RichView Etalon Tuning System
  • Sol Ranger
  • Clamshell Mounting Rings
  • Hard Travel Case
  • Full CEMAX Eyepiece Set
Questions & Answers

Product Questions

No questions yet. Be the first to ask the question!
Support / Downloads