The SolarMax III is a 70mm F/5.7 refractor equipped with 60mm external hydrogen – alpha (H-a) filters. Available in both single-stacked (<0.7Å) and double-stacked (<0.5Å) bandpasses and either 10mm or 15mm blocking filters. What makes the SM3 standout? The SM3 70mm has a new two-speed rack & pinion focuser which creates a more user-friendly interaction with the telescope. The two-speed, 2” focuser has both coarse and fine focus controls allowing the user to get a more precise focus, critical for both solar imaging and visual observing. Additionally, the SM3 70mm includes only external “True” H-a etalon filters giving higher contrast views and sharper features compared with models using smaller internal H-a etalon designs. Experience darker backgrounds, sharper features, and higher contrast with the new SolarMax III series telescope. The SM3 70mm also includes Coronado’s patented RichView tuning allowing direct tuning of the primary etalon filter. The patented RichView tuning technology provides additional tuning range and an overall better way of adjusting the filters bandpass. No other commercially available H-a telescope can provide the tuning range and accuracy of the new SolarMax III telescope. Now you can tune for the highest contrast views of your favorite solar features without sacrificing image quality. Double Stacked models ((<0.5Å bandpass) include two “True” external etalon filters. One etalon filter equipped with our patented RichView tuner and second etalon with tip-tilt tuning using Coronado’s T-Max tuner. Whether you are focusing on the solar edge or surface features in the chromosphere, the SolarMax III 70mm is the solar scope for you. Since both etalon filters are now external to the telescope, you can easily remove both filters and rear blocking filter diagonal to use the scope as a normal refractor for night time astronomy. It’s like having two scopes in one! The new Coronado 70mm SolarMax III series telescope with enhanced rack & pinion focuser and large external etalon(s) are now the perfect way to view the Sun! The SM3 70mm comes with an included 18mm CEMAX eyepiece, Sol Ranger™ Solar Finder, Vixen-style dovetail mounting rail, and an all-new black and gold Aluminum Hard Carry Case. This very high quality 70mm solar telescope features an 400mm focal length, f/5.7 focal ratio, and 15mm blocking filter. Includes mounting rings, Cemax 18mm eyepiece, Sol Ranger solar finder and black & gold aluminum hard carry case. Specifications Clear Aperture 70mm Optical Coatings Fully Multi-Coated Focal Length 400mm Focal Ratio 5.7 Viewfinder Sol Ranger™ Eyepiece(s) CEMAX 18mm, 1.25" Focuser Mechanism 2" Rack and Pinion with 10:1 fine adjustment Diagonal 90 Degree Diagonal with Solar Filters Dovetail Vixen-Style Assembled Product Dimensions 16.3" L x 5.9" W x 5.5" H (41.5cm x 15cm x14cm)- No Hard Case Assembled Product Weight 7.6 lbs.