Detailed information about this product's features  T-Max passband tuner
You save $4951 on the SolarMax 90 during this incredible Coronado sale! From now through September 1, 2008, the Coronado SolarMax 90 telescope is on sale for only $4999! There's no waiting for a rebate check. You simply save $4951 when you buy a SolarMax 90 during this very special limited-time Coronado sale. Coronado is currently quoting delivery in 2 to 3 months after receipt of order. This Coronado SolarMax 90 is a brass and black 800mm focal length 90mm aperture f/8.9 refractor with a built-in sub-Ångstrom Hydrogen-Alpha solar filter. The SolarMax 90 is the largest Hydrogen-Alpha solar telescope ever to be mass-produced and is in use around the world in private observatories and professional research facilities alike. It has been optimized for very high resolution/high contrast visual and photographic imaging of activity on both the solar disk and the Sun’s limb. Prominences leaping off the edges of the solar disk, the explosive upheavals of flares on the face of the Sun, the low contrast mottling of granulation across the face of this nearest of stars, all are captured vividly by this premium-quality solar scope.
The scope’s custom-designed achromatic doublet lens uses special multi-layer antireflection coatings on all air-to-glass surfaces to optimize anti-ghosting and improve contrast. These vacuum-deposited hard coatings will provide a long lifetime of detailed solar observing. The scope delivers both diffraction-limited optical high resolution performance and the extremely high contrast needed to see both subtle surface details and the full explosive power of flares and prominences.
The two-piece solar filter consists of a full-aperture 90mm etalon in front of the objective lens and a 15mm clear aperture blocking filter in the scope’s 1.25" star diagonal. The solar filter has a <0.7 Ångstrom passband, centered on the 6562.8 Ångstrom H-Alpha line. The sub-Ångstrom passband width gives you a superb balance between the visibility of prominences versus disk features. The filter is thermally stable, so there is essentially no drifting off the H-Alpha line as the filter heats up during use. (Thermal stability is 0.005Å per degree Centigrade.) The 15mm clear aperture of the blocking filter portion of the H-Alpha system in the star diagonal is matched in size to the focal length of the telescope to give you full disk views of the Sun.
The SolarMax 90 has two manual drawtubes that extend for rough focusing. One is located between the telescope body and the helical focusing ring around the drawtube. This 2" drawtube should be fully extended for visual work. The helical focuser provides the appropriate final fine focusing of the second manual 1.25" drawtube that projects through the helical focuser and can be extended as needed. This method provides enough back focus to allow both visual observing and prime focus imaging. The 15mm blocking filter aperture allows you to use a Barlow in front of the SolarMax 90’s blocking filter/star diagonal. This makes digital photography easier and allows the use of a binoviewer with the SolarMax.
A T-Max passband tuner is installed between the solar filter etalon and the objective lens. This lets you mechanically tilt the filter’s passband off the H-Alpha line to observe Doppler-shifted solar activity. This will let 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. For more details, click on the “T-Max" icon above.
A full set of 1.25" Coronado CEMAX eyepieces comes standard with the SolarMax 90. These eyepieces use proprietary anti-reflection multicoatings that have been optimized for the highest possible contrast during solar viewing of subtle prominence and surface detail. The set includes 25mm (32x), 18mm (44x), and 12mm (67x) CEMAX eyepieces. Also included, to double the magnification of the supplied CEMAX eyepieces, is the Coronado CEBAR 2x 1.25" Barlow. Like the CEMAX eyepieces, its performance and coatings are optimized for solar observing.
You can also use most 1.25" eyepieces in your collection with the Coronado SolarMax 90. Any good quality 50° field Plössl will work well, as a Plössl’s contrast is generally good and its field wide and flat. For optimum solar detail, however, the Coronado CEMAX eyepieces have a small, but visible, solar viewing contrast advantage over a conventional eyepiece designed for nighttime deep space observing.
A hard carrying case is standard equipment to transport and store the SolarMax 90. The scope comes with a clamshell tube mounting ring that allows you to mount the rather heavy (23 lb.) 30" long scope on most altazimuth and equatorial astronomical mounts. Also included is a Coronado Sol Ranger Sun Finder to make it easy to center the Sun’s image in the eyepiece. The Sol Ranger connects to the SolarMax 90’s clamshell mounting ring.
The SolarMax 90 can be “double stacked" by adding a second SolarMax 90 filter and T-Max to the front of the existing filter. Double filtering improves the scope’s already outstanding <0.7 Ångstrom performance by cutting the passband to a very narrow <0.5 Ångstrom. This improves contrast on very subtle disk features. Two factory-matched “double-stacked" versions of the SolarMax 90 are available at somewhat lower prices (and typically with somewhat higher performance) than simply adding a separate second 90mm filter and the appropriate adapters to the scope yourself at a later date.
One of these narrower passband scopes is the #SM90155, which adds a factory-matched internal 60mm etalon to the standard single 90mm external etalon of the SolarMax 90 scope. The smaller size, and consequently lower cost, of the 60mm internal etalon keeps the price of this dual etalon scope significantly below that of adding a complete second 90mm external etalon.
The second scope, the #SM9015DS, is a true double-stack model that adds a second factory-matched external 90mm etalon in front of the 90mm external etalon of the standard SolarMax 90. The cost is almost the same as adding a second 90mm external etalon yourself separately at a later date, but the factory matching of the etalons provides higher performance than simply adding an unmatched etalon yourself later.
All of the above three versions of the SolarMax 90 are also available with a 30mm blocking filter built into a 2" straight-through eyepiece holder instead of the 15mm blocking filter/1.25" star diagonal combination. These versions let you mount 35mm format film and CCD imaging equipment in a straight-through configuration behind the 30mm blocking filter for full-disk solar images. The single etalon 30mm blocking filter version is our part # SM90307. The dual etalon 30mm blocking filter version is the #SM90305, while the true double-stack 30mm blocking filter version is the #SM9030DS. These versions are all provided with 2" to 1.25" adapter and a standard (no blocking filter) 1.25" star diagonal to let you use the supplied 1.25" CEMAX eyepieces for visual observing.
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