Coronado SolarMax III 90 Double Stack Solar Scope with BF30
- This flagship model of the Coronado solar telescope series is designed for seeing stunning high contrast hydrogen-alpha details of solar prominences, sunspots, active flare regions, and surface granulation
- Includes Coronado's patented RichView tuning system, coupled with the T-Max Tuner to maximize the contrast and detail of the features being observed
- Includes the BF30 straight through 2" blocking filter and a 1.25" diagonal, to provide the largest unvignetted view of the Coronado BF series, and to provide a straight-through optical path, ideal for large sensor camera models
- This double stack (two stacked etalons) system provides a bandpass of <0.5 Angstroms for even higher surface contrast and detail than a single-stack (<0.7 A) system can produce
- Includes three CEMAX eyepieces, a 2x Barlow lens, 1.25" star diagonal, the Sol Ranger viewfinder, and a hard carry case to protect your investment.
The Coronado SolarMax III 90mm Double Stack Solar Scope refractor is the ultimate telescope for viewing stunning details of our nearest star. Lightweight, compact, and includes a sturdy hard shelled carrying case with foam interior — allowing you to take this hydrogen-alpha (H-α) telescope anywhere in the world with you, whether it be your own backyard or chasing down the next great solar eclipse! This is the flagship model of the entire Coronado solar telescope line, featuring a double stack front etalon system coupled with the largest BF30 straight through blocking filter. Read on to dive into all the features!
Designed and Manufactured in North America. The Coronado SolarMax III 90mm lens blanks are manufactured in the USA for Meade.
The heart of this SolarMax III 90mm is the double stacked system of two front external 90mm air-spaced etalons that provide views of the most stunning part of the solar spectrum — Hydrogen-alpha light (6562.8 Angstroms), which is where many of the beautiful features of the solar disk and atmosphere radiate best. And with a bandpass of <0.5 Angstroms (Å), contrast is exceptional for seeing prominences spilling off the edge of the solar disk, as well as surface features including sunspots, filaments, active flare regions, plages and surface granulation. Compared with the single stack version of this telescope (which provides a >0.7 Å bandpass), the ultra-narrow >0.5 Å of this system enhances contrast even further for surface detail exploration. And the resolution enhancement over the 70mm telescope provides more details at any magnification. The resulting detail and contrast improvements on filaments, flares and surface granulation detail will add noticeable pop to the view in your eyepiece, making the double stack 90mm system well worth the investment.
An integral part of making this system safe for solar viewing is the 2" 30mm blocking filter (BF30), located between the 1.25" diagonal and the telescope focuser. It consists of multiple internal filters such as the Induced Transmission Filter (ITF), Blue Glass Filter (BG38), and H-a cut-off filter. The BF30 uses a 30mm clear aperture H-a cutoff filter which provides a full unvignetted image with the included eyepieces. Compared with the smaller BF10 and BF15 models, this BF30 provides the largest unvignetted field of any Coronado telescope — useful when viewing features with higher magnification or imaging with larger camera sensors. In addition, unlike the BF10/15 which is built into the diagonal housing itself, the BF30 is a straight-through design located in front of the diagonal, which you'll find is much more convenient when attaching a DSLR or other dedicated astro camera. The BF30 will accept any 2" eyepiece or imaging equipment with 2" nosepiece as well as 1.25" accessories when using the included 2" to 1.25" zero-length adapter. The included 1.25" diagonal is pre-threaded onto the BF30 filter assembly to allow for visual observation out of the box. The 1.25" diagonal attachment also includes t-threads on the top edge, allowing camera attachment behind the diagonal as well. The SolarMax III 90 features an 800mm focal length (f/8.9) refractor doublet lens with 90mm aperture yielding a clean, high contrast image across the field of view.
Tuning the image of the sun for optimal contrast is made possible with Coronado's patented RichView tuning technology, which adjusts the distance between the parallel glass plates of the outer external etalon in order to achieve the perfect wavelength bandpass for the feature you are observing, all while maintaining precise optical alignment. This patented technology provides additional etalon tuning range and also allows the SolarMax III to be used at high altitude observing locations. The RichView system simply allows for better control over your H-a bandpass window. In addition to RichView tuning, the included T-Max Tuner built into each etalon allows you to tune in the brightest image and remove any reflections from the image. Combined, the RichView and T-Max together offer unparalleled image tuning to get the best possible view of solar details!
The telescope includes a backlash free 2" dual-speed rack & pinion focuser with course and fine focus (10:1 reduction) and a Sol Ranger Solar Finder, which is a quick and easy way to aim at the sun. Optical accessories that come standard with the SolarMax III 90mm include 25mm, 18mm, and 12mm CEMAX eyepieces, the CEMAX 2x 1.25" Barlow, and a 1.25" diagonal that threads directly into the back of the BF30. Also included is a 2" visual back for using 2" accessories with the BF30, a 2"-1.25" zero-length adapter, Vixen-style dovetail mounting rail and an all-new black and silver aluminum hard carry case (Dimensions: 26.5" x 8.66" x 8.66").
Coronado assures that all solar filters and solar telescopes are tested at specialized labs that are accredited to verify compliance with the ISO 12312-2 safety specifications for solar viewing.
Download or view our Solar Glossary.
- Best for viewing
- User level
- Optical design
- Optical diameter
- Focal length
- Focal ratio
- Fully multi-coated
- Cemax 25.0mm (1.25")
- Magnification with included eyepieces
- 32x, 67x
- Resolving power
- Lowest useful magnification
- Highest useful magnification
- Highest theoretical magnification
- Limiting stellar magnitude
- Optical quality
- Diffraction limited
- Finder scope
- Sol Ranger
- 2" dual-speed Rack-and-pinion
- Diagonal degrees
- 1.25" 90° Mirror Star
- Mount type
- Optical Tube without Mount
- Tube material
- T-max tuner
- Additional included accessories
- 12mm, 18mm, 25mm CEMAX eyepieces, CEMAX 2x Barlow, BF30 blocking filter and 1.25" star diagonal, Vixen-style dovetail bar, carry case
- Other features
- Double-stacked etalons for 0.5 angstrom bandpass, Dual-speed focuser
- Five year