Coronado SolarMax III 70 Double Stack F/5.7 solar telescope with 10mm blocking filter


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The 70mm Coronado SolarMax III 70 DS dual-etalon solar telescope has a very narrow <0.5 Ångstrom passband H-Alpha solar filter with unique RichView tuning. Its 10mm blocking filter provides you with extra-high contrast views and binoviews of solar surface features, as well as good views of solar prominences and more . . .
Our Product #: SM7010DS
Coronado Product #: 324004
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Product Description

This Coronado SolarMax III 70 DS Hydrogen-Alpha solar telescope by Meade is "double-stacked," with two filter etalons for increased contrast of solar disk features. 

Double-stacking the etalons improves the scope's already outstanding resolution and contrast by cutting the single etalon model's narrow <0.7 Ångstrom passband to a very narrow <0.5 Ångstrom. Narrowing the passband improves the contrast and visibility of subtle disk features, although it slightly reduces the brightness of prominences. For maximum prominence brightness, the front etalon of the SolarMax II 60 DS can be removed to let the scope function as a single etalon solar scope providing a <0.7 Ångstrom passband. The 10mm clear aperture blocking filter is designed for binoviewing and imaging with medium (APS-C) chip size DSLR and CCD cameras in both single and double etalon configurations.

The Coronado SolarMax III 70 DS is designed to do much more for you than merely show you sunspots, as an ordinary white light solar filter can. The SolarMax III 70 DS will reveal the ever-changing tapestry of prominences leaping off the edges of the solar disk, the explosive upheavals of flares on the face of the Sun, and the subtle mottling of granulation across the face of this nearest of stars. And it will let you image all of it in exquisite detail.

The three-piece solar filter consists of a 60mm etalon, a second 60mm etalon at the front of the scope and a 10mm clear aperture blocking filter in the scope's 1.25" star diagonal. The dual-etalon "double-stacked" solar filter has a <0.5 Ångstrom passband, centered on the 6562.8 Ångstrom H-Alpha line. The very narrow passband width gives you higher contrast on disk details than a single etalon system, with only a slight reduction in prominence brightness. The filters are thermally stable, so there is no drifting off the H-Alpha line as the filters heat up during extended use.

The 10mm clear aperture of the blocking filter built into the star diagonal is designed to provide full disk views of the Sun for visual use and imaging.  There are also 15mm blocking filter versions that are well-suited for binoviewer use and for imagers who need a wider illuminated field for use with larger chip DSLR and CCD cameras.

The joint action of the individually tuned etalons lets you observe Doppler-shifted solar activity with exceptional finesse and subtlety. This lets you determine whether Doppler-shifted features, such as flares, are moving towards you or away from you as they leap off the surface of the Sun. No other commercially available H-Alpha telescope can provide the tuning range and accuracy of the SolarMax II DS. Now you can tune for the highest contrast views of active regions, flares, filaments, and other surface detail at a finger's touch, then quickly and easily re-tune for prominences on the solar limb.

The SolarMax III 70 DS has a 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. This method provides enough back focus to allow both visual observing and imaging with medium chip size DSLR and CCD cameras.

The Coronado Cemax 18mm eyepiece comes as standard equipment.  A 25mm, 18mm, 12mm and the CEMAX 2x barlow are available as optional equipment. You can use most 1.25" eyepieces with the Coronado SolarMax III 70 DS, as well. Any good quality 50° field Plössls will work well, as their contrast is generally good and their fields are wide and flat. 

A hard carrying case is standard equipment to transport and store the 70mm Coronado SolarMax III DS. A 1/4"-20 thread tripod adapter socket is built into the scope's dual mounting rings to allow using the SolarMax III DS telescope on a suitably-sturdy photo tripod, as well as on most astronomical mounts by adding an optional dovetail mounting plate. The supplied Coronado Sol Ranger Sun Finder makes it easy to center the Sun's image in the eyepiece. The Sol Ranger connects to the supplied SolarMax III DS mounting rings as can be seen in the image above.

Tech Details

Aperture 70mm
Binary and Star Cluster Observation No
Focal Length 400mm
Focal Ratio f/5.7
Galaxy and Nebula Observation No
Lunar Observation No
Weight 8 lbs.
Planetary Observation No
Resolution 1.93 arc seconds
Warranty 5 years


Review by:
As a total solar junkie with solar scopes from 40mm to 200mm aperture, I'm critical on these instruments these days. The older SMII series were not something I would suggest due to several poor design choices, however the new SMIII series are excellent and I highly recommend them! The SMIII70 is a great full disc solar imaging scope. Both etalons are front mounted which is ideal for angle of entry to avoid really dark limbs. The double stack option is excellent to remove the double limb and increase contrast. The scope itself comes with a good crayford focuser (this is a big deal for imaging compared to the previous helical ones). And the scope itself is a good 70mm achromatic doublet which is great for imaging solar in any wavelength with additional filters if you take the front etalons off (no more swapping scopes!) so you can image white light, calcium and HA from this one scope with a few additional filters and not have to swap scopes around. That's versatile and excellent. (Posted on 8/3/2019)
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