Meade - 12 " LX200-ACF Advanced Coma-Free Telescope with UHTC

The most widely used research telescope on earth now comes with the most advanced optical system in space. Meade's all new LX200-ACF brings Advanced Coma-Free optics within reach of aspiring astronomers everywhere. Nearly every observatory reflector in the world is a Coma-Free, including NASA's Hubble Space Telescope. Now you can own what the professionals own. The LX200-ACF includes all the field-proven features of the LX200 including GPS, Primary Mirror Lock, Oversized Primary Mirror, SmartDrive™, Smart Mount™, AutoStar™® II and more. Plus, the LX200-ACF comes with observatory-class optics crafted in Irvine, California, and a Series 5000 26mm 5-Element Plossl eyepiece. The new LX200-ACF. It's the biggest news in astronomy since, well, the LX200.

The 'advanced' in Advanced Coma-Free.
A traditional Ritchey-Chretien (RC) is a type of reflector that delivers a coma-free, flat field of view via hyperbolic primary and secondary mirrors. RC telescopes (from a variety of manufacturers) are found in most of the world's top observatories and NASA's Hubble Space Telescope. Because the mirrors in these telescopes have always been very expensive to make, few amateur astronomers could enjoy them. Fortunately, Meade engineers developed a radical new Advanced Coma-Free design by combining a hyperbolic secondary mirror with a corrector-lens-and-spherical-primary-mirror combination that performs as one hyperbolic element. This Advanced version of the traditional RC design produces a coma-free, flat field of view that rivals traditional RC telescopes at a fraction of the cost. The design even eliminates diffraction spikes and improves astigmatism, both of which are inherent in the traditional RC design. When reviewing Meade's LX400-ACF Advanced Coma-Free, Sky and Telescope magazine said, '[It] does indeed perform like a Ritchey-Chretien. The difference between the off-axis images (compared to a Schmidt-Cassegrain) was dramatic to say the least.'

f/10 Advanced Coma-Free Optics:
Building upon the classic RC design Meade has created a design with the same coma free pinpoint star images and flatter field that discerning astrophotographers and most professional observatories have come to expect from classic Ritchey-Chretien optics. Meade's Advanced Coma-Free system also reduces the astigmatism and eliminates diffractions spikes found in classical RCs. The LX200-ACF is the perfect platform for the demanding researcher and imaging enthusiast with telescopes available in apertures of 8 inches, 10 inches, 12 inches, 14 inches, and 16 inches.

Meade Ultra-High Transmission Coatings (UHTC™) increases total light transmission and image brightness by nearly 20% over Meade's standard coatings. Objects such as stars, galaxies and nebulae will appear significantly brighter.

Primary Mirror Lock locks the mirror in place during long-exposure astrophotography.

Oversize Primary Mirror diameters are greater than their listed aperture (e.g., the diameter of the 8' LX200-ACF is actually 8.25'). This additional 1/4' yields a wide, fully illuminated field-of-view.

Smart Mount™ constantly refines pointing accuracy each time an object is centered and updated. Compatible with both equatorial and altazimuth mounts.

Smart Drive™ provides permanent periodic error correction (PPEC) on both axes by learning and averaging error over the course of one or more training periods, thereby minimizing guiding corrections during long-exposure photographs. PPEC is available on both axes and functions in both polar and altazimuth modes.

Sony™®GPS Receiver Sensor automatically inputs precise time, date, and geographical location to help quickly and precisely align the telescope.

AutoAlign™ 'Telescopes with Meade's new AutoAlign come pre-aligned.They are smart scopes that know the night sky right out of the box. AutoAlign picks two fail-proof alignment stars for you and places them right in your view-finder. Just center them to fine tune your alignment and the wonders of the universe are at your fingertips.

AutoStar™® II controller features 'Hot Keys' for quick access to a 145,000 celestial object database. AutoStar II can be updated with the latest software upgrades, guided tours and timely objects like comets free at meade.com.

LX200-ACF Advanced Coma-Free Optical Tube Assemblies

UHTC

An important optional feature to optimize the performance of your Meade telescope. Image brightness in a telescope is crucially dependent on the reflectivity of the telescope's mirrors and on the transmission of its lenses. Neither of these processes, mirror-reflectivity or lens-transmission, is, however, perfect; light loss occurs in each instance where light is reflected or transmitted. Uncoated glass, for example, reflects about 4% of the light impacting it; in the case of an uncoated lens 4% of the light is lost at entrance to and at exit from the lens, for a total light loss of about 8%.

Early reflecting telescopes of the 1700's and 1800's suffered greatly from mirrors of poor reflectivity- reflection losses of 50% or more were not uncommon. Later, silvered mirrors improved reflectivity, but at high cost and with poor durability. Modern optical coatings have succeeded in reducing mirror-reflection and lens-transmission losses to acceptable levels at reasonable cost.

Meade Standard Coatings: The optical surfaces of all Meade telescopes include high-grade optical coatings fully consistent in quality with the precision of the optical surfaces themselves. These standard-equipment coatings include mirror surfaces of highly purified aluminum, vacuum-deposited at high temperature and overcoated with silicon monoxide (SiO), and correcting lenses coated on both sides for high light transmission with magnesium fluoride (MgF2). Meade standard mirror and lens coatings equal or exceed the reflectivity and transmission, respectively, of virtually any optical coatings currently offered in the commercial telescope industry.

The Meade UHTC Group: Technologies recently developed at the Meade Irvine coatings facility, however, including installation of some of the largest and most advanced vacuum coating instrumentation currently available, have permitted the vacuum-deposition of a series of exotic optical coatings precisely tuned to optimize the visual, photographic, and CCD imaging performance of Meade telescopes. These specialized, and extremely advantageous, coatings are offered here as the Meade Ultra-High Transmission Coatings (UHTC) group, a coatings group available optionally on many Meade telescope models.

In Meade catadioptric, or mirror-lens, telescopes (including the ETX-90EC, ETX-105EC and ETX-125EC; LX10, LX90, and LX200GPS Schmidt-Cassegrains; and LXD55-Series Schmidt-Newtonians) before incoming light is brought to a focus, it passes through, or is reflected by, four optical surfaces: the front surface of the correcting lens, the rear surface of the correcting lens, the primary mirror, and the secondary mirror. Each of these four surfaces results in some loss of light, with the level of loss being dependent on the chemistry of each surface's optical coatings and on the wavelength of light. (Standard aluminum mirror coatings, for example, typically have their highest reflectivity in the yellow region of the visual spectrum, at a wavelength of about 580nm.)

Mirror Coatings: Meade ETX, Schmidt-Cassegrain, and Schmidt-Newtonian telescopes equipped with the Ultra-High Transmission Coatings group include primary and secondary mirrors coated with aluminum enhanced with a complex stack of multi-layer coatings of titanium dioxide (TiO2) and silicon dioxide (SiO2). The thickness of each coating layer precisely controlled to within +/-1% of optimal thickness. The result is a dramatic increase in mirror reflectivity across the entire visible spectrum; at the important hydrogen-alpha wavelength of 656nm. - the predominant wavelength of emission nebulae - reflectivity is increased from 89% to over 97%.

Correcting Lens Coatings: Meade telescopes ordered with the UHTC group include, in addition, an exotic and tightly-controlled series of coatings on both sides of the correcting lens or correcting plate, coatings which include multiple layers of aluminum oxide (Al2O3), titanium dioxide (TiO2), and magnesium fluoride (MgF2). Per-surface light transmission of the correcting lens is thereby increased at the yellow wavelength of 580nm., for example, to 99.8%, versus a per-surface transmission of 98.7% for the standard coating.

The importance of the UHTC group becomes apparent when comparing total telescope light transmission, or throughput, caused by the multiplier, or compounding, effect of the four optical surfaces. With each optical surface contributing significantly to telescope light throughput, the effect of all four surfaces combined is indeed dramatic, as demonstrated by the graphs on the facing page, as well as by the table of the brightest nebular emission lines. At the H-alpha wavelength of 656nm., total transmission increases from 77% to 93%, an increase of 93/77 or 21% at all three nitrogen-III and sulfur-II wavelengths of 655nm. and 673nm.- prominent lines in certain galactic nuclei and in supernova remnanats such as the Crab Nebula- transmission increases by 21%; ; at the helium wavelengths of 588nm. and 469nm. - strong emission lines in hot planetary nebulae - total telescope transmission increases by 18% and 19%, respectively; at the two nitrogen II lines of 655nm. and 658nm. and at the sulfur II line of 673nm., transmission is increased by 21%. Averaged over the entire visible spectrum (450nm. to 700nm.), total light transmission to the telescope focus increases by about 20%.

Observing with the UHTC: Meade ETX, Schmidt-Cassegrain, and Schmidt-Newtonian telescopes equipped with the UHTC present dramatically enhanced detail on the full range of celestial objects - from emission and planetary nebulae such as M8, M20, and M57 to star clusters and galaxies such as M3, M13, and M101. Observations of the Moon and planets, since they are observed in reflected (white) sunlight, benefit in image brightness from the full spectrum of increased transmission. The overall effect of the UHTC is, as it relates to image brightness, to increase the telescope's effective aperture. Image brightness (i.e., the ability to see faint detail) of the Meade 10" LX200GPS is, for example, effectively increased by about one full inch of aperture.

* The % increase is obtained by dividing the UHTC-transmission (column 4) by the standard coatings transmission (column 3).

Effects on CCD Imaging: While the human eye loses sensitivity to light beyond wavelengths of about 700nm., CCD imaging chips remain sensitive to about 750nm. and longer, wavelengths at which the reflectivity of an aluminum coating is near its lowpoint. Importantly, however, the UHTC's total light transmission at 750nm. is 83%, vs. 72% for standard coatings, an increase of 83/72, or 15%.