Meade 12" LX200-ACF Advanced Coma-Free with UHTC OTA
If you have been waiting to buy a telescope, either for your own use or as a gift for someone, you won't go wrong with a choice like the Meade LX-200 ACF 12 inch Computerized Telescope. You may ask - Why? When there are hundreds of others to chose from, why pick one from the Meade LX200 series of scopes? Well, to explain that, let's get a little technical, shall we?. But understand one thing. Once you get a Meade in your backyard, literally, the sky is the limit!
Firstly, a Meade LX200 telescope is what's known as a Catadioptric scope. What this means is that it uses a combination of lenses (dioptrics) and mirrors (catoptric) in its design to provide viewers with precise and crisp images of the great beyond. Meade uses patented f/10.0 optical technology, which blends the best of breed in refraction and reflection sciences, to produce its coma free telescope. This technology enables these scopes to display planetary objects in a tight circle from the middle to the field's edge.
A coma free telescope? What's that, you ask. Well, if you wear distance spectacles or lenses, here's an experiment you can conduct. Remove your vision-enabling aids and stare at something at a distance. You will notice the object looks a bit hazy and blurry at the edges. Now put on your viewing aids and look again. You have a much clearer picture, for sure. And that's what "coma" is. It is an optical deviation that causes distortions in our vision.
Based on Meade's Advanced Coma Free (ACF) technology, the Meade LX-200 ACF 12 inch Computerized Telescope produces sharp, clear and bright images. Since ACF optics cause starlight to be concentrated much more precisely, devoid of coma or diffraction spikes, the stars look perfectly rounded and not like the crescent shaped versions you would get with other devices. And that means your coma free telescope can pick up and show you stars and other celestial objects that are fainter and much more distant than ever before. Only telescopes in the Meade LX200 series offer this feature. No other competing manufacturer offering Schmidt-Cassegrain scopes can claim that honor.
And that's not the only optical technology innovation that Meade uses in the Meade LX-200 ACF 12 inch Computerized Telescope to make your heavenly viewing an experience to remember. Taking into account that the human eye has limited capacity to process images beyond wavelengths of 700nm, Meade introduced its innovative Meade Ultra-High Transmission Coatings (UHTC™) for lenses used in the Meade LX200 telescopes. This pioneering technology is radically more advanced than conventional Meade coatings - up to 20% more effective. What this has done is to break that 700nm barrier and push it to 750nm, allowing you to now view crisper, sharper, brighter and clearer cosmos images.
Whether you are a seasoned researcher, or whether you are an armature galaxy explorer, a Meade coma free telescope has more technology in store to impress you and your star-gazing party guests. Your Meade LX-200 ACF 12 inch Computerized Telescope will come equipped with an ultra-precise powerful 16-channel Sony GPS receiver that can capture coordinates for celestial objects, and then automatically position your scope to point to the selected object. Pretty impressive, huh? Well, that's not all. Read on for more!
With every Meade LX200 scope, you get the power of Meade AutoStar II. And what exactly is that, you might ask? Well, the Meade AutoStar II is a comprehensive yet compact astronomical software that has access to a database containing the coordinates of approximately 145,000 celestial objects. With its built-in intelligence, this software works in unison with the Sony GPS to seek and locate objects in the sky, and then automatically align the scope to view the target object. All you have to do is set up your Meade LX200, select a target heavenly body from the AutoStar flash memory-based database using HotKey features provided, and watch the GO TO feature align the scope (~1 arc minute) accurately to your target. Now all you have to do is lean forward, place your eye to the eye-piece and enjoy the heavenly show! And the best part is that updates to the Meade AutoStar II software can easily be downloaded from Meade's website whenever they are released.
No more awkward wrestling of the scope, to position it just correctly, when you buy a Meade LX-200 ACF 12 inch Computerized Telescope. Your scope will come with a heavy duty mount with dual forks so that you can manoeuvre the scope with comfort and ease. With this high quality mount, star gazers can control the amount of swerve they want from their coma free telescope to just the right amount. Swerve as fast as 1 to 8 degrees every second with increments of .1 degrees per second, or fine swerve to .01x to 1x sidereal in 1 1/100th increments, enabling you precise and accurate viewing every time.
Meade understands that once you locate a heavenly sight, you may sometimes want to view it for a long time - maybe even for hours. That's why each Meade LX-200 comes with unique Zero Image Shift Microfocuser technology. With its unique lock knob feature, the Meade LX-200 ACF 12 inch Computerized Telescope provides a mechanism to lock the primary mirror in place once you have selected your viewing object. This will now cancel any shifts in the image being observed, allowing you to enjoy the selected sight for many hours to come.
With all these innovations and technological features built in, what's not to like about the Meade LX-200 ACF 12 inch Computerized Telescope - except maybe for the fact that you don't yet own one!
The 12" LX200-ACF OTA can also be bought with Meade's own 3 Year Sky Assurance.
LX200-ACF Advanced Coma-Free Optical Tube Assemblies
|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.
|Emission Line||Wavelength (nm.)||Transmission: Standard Coatings (%)||Transmission: UHTC Group (%)||Increase*|
* 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%.
|Batteries||8 x C cells (20 hours life)|
|Eyepieces||Series 4000 26mm Super Plossl|
|Included Accessories||16-channel GPS receiver,|
|Mounting connections||heavy-duty fork type, double tine|
|Optical Design||Advanced Coma-Free (ACF) with UHTC|
|Primary Mirror||Progessive tension primary mirror|
|Slew Speeds||RA and Dec: 0.01x to 1.0x sidereal, variable in 0.01x increments; 2x, 8x, 16x, 64x, 128x sidereal; 1º per second to 8º per second, variable in 0.1º increments|
|Tracking Rates||sidereal, lunar, or custom selected from 2000 incremental rates|
|Viewfinder||8 x 50mm|