Coronado SolarMax 40 H-Alpha <0.7A Solar Telescope - BF10

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Coronado SolarMax 40 H-Alpha <0.7A Solar Telescope - BF10   Discontinued
Item # CI-SM40T10
  • Brass 400mm focal length 40mm aperture f/10 refractor custom-built to optimize the performance of the Coronado Instruments SolarMax 40 Hydrogen-Alpha solar filter.
  • The Coronado SolarMax 40 was engineered strictly for solar observing by well-known optical designer, Dick Buchroeder.
  • Special multi-layer anti reflection coatings on all air-glass surfaces to optimize anti-ghosting.
  • The Coronado SolarMax 40 has a sub-ngstrom passband width gives you an ideal balance of prominence and surface detail.
  • This model comes with a BF10 Blocking Filter, TMax Tuner, Clamshell Ring, Sol Ranger Finderscope, Travel Case and Five Year Coronado Warranty.


Coronado SolarMax 40 H-Alpha Telescope with BF10 Blocking Filter

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 nor the image quality. Most broadband coatings, used on such telescopes, will have reduced effectiveness at this wavelength and telescopes (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. The SolarMax 40 has the same aperture as the P.S.T. but is distinguished by several key factors. The SolarMax 40 comes standard with a < 0.7 angstrom bandpass which results in increased surface detail across the disk. A T-Max attached directly behind the etalon gives you the ability to adjust for Doppler shifted light. Bino-viewers and most imaging equipment will come to focus, sometimes with the use of a Barlow or OCS. These features plus enhanced surface detail make the SolarMax 40 a more versatile instrument with remarkable solar images.

With the SolarMax 40 you will see all of the limb detail of the P.S.T. but with enhanced surface features. The SolarMax 40 comes standard with a BF5 blocking filter but a BF10 version is also available and recommended for use with imaging equipment and bino-viewers. The larger blocking filter allows you to extend the focal length without vignetting but does not enhance detail or lower the bandpass. You can also purchase a second SolarMax 40 / T-Max filter, along with a small adaptor plate, and attach these to the front in order to lower the bandpass to < 0.5 angstroms. This is called ‘double stacking’ and further enhances surface detail.

This Coronado SolarMax 40 is a handsome brass and black f/10 refractor with 400mm focal length and 40mm aperture. Its purpose is simple. The Coronado SolarMax 40 was custom-built to optimize the performance of the SolarMax 40 Hydrogen-Alpha solar filter. The SolarMax 40 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 40, when properly cared for, will last a lifetime.

At the heart of the SolarMax 40, a two-piece solar filter is formed from a full-aperture 40mm etalon positioned in front of the objective lens and a 10mm clear aperture blocking filter incorporated into the diagonal. The solar filter has a <0.7 Ångstrom passband, centered on the 6562.8 Ångstrom H-Alpha line and the sub-Ångstrom passband width gives a perfect balance of prominence and surface features. The assembly is thermally stable at 0.005Å per degree Centigrade, so there is no drifting off the H-Alpha line as the filter heats up during normal observing. The 10mm clear aperture blocking filter is perfectly matched to the focal length of the telescope to give full disk views of the Sun.

On the outside, the Coronado Solar Max 40 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 T-Max 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 40 Features...

  • Threaded, Protective Metal Cover For Primary Lens.
  • Deluxe Hard Carrying Case.
  • Clamshell Mounting Rings w/1/4"-20 Thread Tripod Adapter.
  • Solar Max 40 Can Be "Double Stacked"!
Coronado Product Number: SM40T10
Additional Information

Additional Information

Solar Instrument Type Telescope
Aperture 35mm - 50mm
Emission Line H-Alpha
Manufacturer Coronado
Warranty 1 Year Warranty
Blocking or ERF Aperture 10mm
Bandwidth <0.7 A
Telescope Focal Length 400mm
Telescope Focal Ratio f/10
Tuner Included? Yes
Length of Optical Tube 16.75"
Optical Tube Weight 3 lbs.
Included Items

Included Items

  • SolarMax 40 <0.7A
  • TMax
  • BF10 Blocking Filter
  • Clamshell Mounting Rings
  • Sol Ranger
  • Travel Case
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