Coronado SolarMax III 70 Double Stack Solar Scope with BF15
Item #57001
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This flagship double stacked 70mm solar telescope features a 400mm focal length, f/5.7 focal ratio, and 15mm blocking filter. Includes mounting rings, CEMAX 18mm eyepiece, Sol Ranger solar finder and black and silver aluminum hard carry case.
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  • More Info
    • This flagship model of the Coronado 70mm 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 BF15 blocking filter provides a larger unvignetted view of the solar disk compared with the BF10 and accepts 1.25" eyepieces or imaging equipment (42mm t-thread compatible)
    • 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 the Sol Ranger viewfinder as well as a hard carry case to protect your investment.

    The Coronado SolarMax III 70mm refractor is the perfect 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 70mm line, featuring a dual stack front etalon coupled with the larger BF15 blocking filter. Read on to dive into all the features!

    Designed and Manufactured in North America.

    The heart of this SolarMax III 70mm is the double stacked system of two front external 60mm 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 (), 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 bandpass), the ultra-narrow >0.5 of this system enhances contrast even further for surface detail exploration. The resulting contrast improvements on filaments, flares and surface granulation detail will add noticeable pop to the view in your eyepiece, making the double stack system well worth the investment.

    Another integral part of making this system safe for solar viewing is the 15mm blocking filter (BF15), located inside the diagonal holder below the eyepiece. It consists of multiple internal filters such as the Induced Transmission Filter (ITF), Long Wave Pass filter (LWP), and H-a cut-off filter. All BF15s use a 15mm clear aperture H-a cutoff filter which provides a full unvignetted image of the Sun with the included eyepiece. Compared with the smaller BF10, this BF15 provides an even larger unvignetted area around the disk of the sun — useful when viewing features at higher magnifications or imaging with larger camera sensors. The BF15 will accept any 1.25" eyepiece or imaging equipment with t-thread. The SolarMax III 70 features a 400mm focal length (f/5.7) refractor with 70mm objective lens 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!

    Solar Disk Detail Image

    The Sun in hydrogen-alpha light showing some of the different features visible around the solar disk.

    As if having a dedicated solar filter telescope wasn't enough, the SolarMax III can also double for night sky astronomy and/or daytime spotting! Because the etalons and blocking filter are external to the refractor optics, simply unthread the front etalons, and substitute in a standard star diagonal (either 1.25" or 2") into the 2" focuser, and you have a beautifully crafted 70mm wide field doublet refractor, ready to observe planets, star clusters, and even brighter nebulae and galaxies. And during the day, the telescope makes a fantastic spotting scope for either birdwatching or simply taking in the distant vistas. Truly a versatile telescope!

    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. Also included is an 18mm CEMAX eyepiece, Vixen-style dovetail mounting rail, and an all-new black and silver aluminum hard carry case (Dimensions: 27.8" x 10.2" x 10.2").

    The SolarMax III 70mm telescope is a portable and versatile way to view our closest star. You can even attach a camera to record those stunning displays of flares and prominences during an eclipse, or just any clear day when the sun is out. And don't forget you can remove the filters and use the 70mm refractor as a rich-field refractor for general night sky viewing and daytime spotting. Hand assembled and solar tested before being sealed in the box — get yours today and start enjoying the spectaculars views the SolarMax III telescope provides!

    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.


    Limited Warranty against defects in materials or workmanship for five years from date of purchase. This warranty is provided by Meade for the benefit of the original retail purchaser only. For complete warranty details contact Meade at 800-626-3233.

    Product Support

    Visit our product support section for instruction manuals and more

  • Specs
    • Best for viewing:
    • User level:
    • Optical design:
    • Optical diameter:
    • Focal length:
    • Focal ratio:
    • Coatings:
      Fully multi-coated
    • Eyepieces:
      Cemax 18.0mm (1.25")
    • Magnification with included eyepieces:
    • Resolving power:
    • Lowest useful magnification:
    • Highest useful magnification:
    • Highest theoretical magnification:
    • Limiting stellar magnitude:
    • Optical quality:
      Diffraction limited
    • Finder scope:
      Sol Ranger
    • Focuser:
      2" dual-speed Rack-and-pinion
    • Diagonal degrees:
      1.25" 90° Blocking Filter Blocking Filter
    • Mount type:
      Optical Tube without Mount
    • Tube material:
    • Length of optical tube:
      19.3 in.
    • Weight, optical tube:
      9.3 lbs.
    • Additional included accessories:
      Black and silver hard carry case, Vixen dovetail bar, BF15 blocking filter
    • Other features:
      Double-stacked etalons for 0.5 angstrom bandpass, Dual-speed focuser
    • Warranty:
      Five year
    • T-max Tuner:
  • Important Shipping Information

    When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available.

    A per-item shipping charge (in addition to the standard shipping and handling charge) applies to this product due to its size and weight. This charge varies based on the shipping method.

    Standard Delivery: $0.00

    Standard Delivery to Canada: $75.00
    3 Day Delivery: $140.00
    2 Day Delivery: $140.00
    Next Day Delivery: $160.00


    This product is available to ship Standard delivery US except for delivery to Alaska and Hawaii. Delivery is not available to US territories/protectorates or APO/DPO/FPO addresses. Delivery is available to Canada.