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Second Hand Meade RCX400 12" Telescope

 

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Generally In Stock, Please Confirm Before Ordering  

Generally In Stock, Please Confirm Before Ordering

Model:  RCX40012
Brand:  Meade

Second Hand Meade RCX400 12'' Telescope
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This is a superb example of these wonderful telescopes. The Meade RCX 400 12". Huge aperture to give crisp, sharp and detailed views. The clever computerized system, makes locating objects a breeze. You can also collimate the telescope using the handset. A fantastic telescope making large aperture observing easy and enjoyable. The optics have been cleaned on this model so as you can see from the images, the optics are truly pristine.

This model has been personally field tested by us. It gave outstanding results. The collimation was achieved with ease. After that, the telescope provides pin point star images to a level rarely seen. We are that impressed with this telescope, we were tempted to keep it!

This telescope comes with all the standard accessories such as the 2" diagonal, Series 5000 24mm 2" eyepiece and a magnified finderscope. An image with all the included accessories is pictured above.

Please note this is a very large and heavy telescope. It's a 2 man job to transport it around so this is an observatory class telescope. Not ideal if you want a portable instrument.

Due to the size and weight of this telescope, we are unable to ship it out. This is a collection item only.

Some information about these superb telescope is detailed below. If you have any questions, then please give us a ring.

The RCX-400 telescope from Meade Instruments Corporation is advertised as an “Advanced RitcheyChrétien
Optical System”. Here, we will explore these claims and compare the optical performance to that
of previous Schmidt-Cassegrain (SCT) designs and a true Ritchey-Chrétien (RC) design, as defined in the
literature.

The RC design is actually a special case of the Classical Cassegrain (CC) two-mirror reflecting telescope
design. In this design, a primary and secondary mirror is arranged so that the light collected by the
primary is reflected to the secondary and then back through a hole in the primary to a focus behind the
primary. The CC is defined by the curvature of the mirrors to be a parabolic primary and a strong
hyperbolic secondary. By proper choice of mirror curves, the telescope can be made to have zero
spherical aberration. “Spherical aberration occurs when light rays parallel to the optical axis entering a
system come to a focus at different points along the axis”1
. However, the next aberration that is
significant is coma, which “occurs in an oblique bundle of light when the intersection of the rays is not
symmetrical but is shifted with respect to the axis of the bundle”2
. By using a hyperbolic primary and a
hyperbolic secondary, and with proper mirror spacing, both spherical aberration and coma can be
minimized.
Again, this is a reflecting telescope design with no refractive elements. Refractive elements are to be
avoided if chromatic aberration is to be minimized. Chromatic aberration occurs when different light
wavelengths come to focus at different points, due to the refractive nature of glass. If there is no
refractive element, there is no chromatic aberration.

The RC design is actually a special case of the Classical Cassegrain (CC) two-mirror reflecting telescope
design. In this design, a primary and secondary mirror is arranged so that the light collected by the
primary is reflected to the secondary and then back through a hole in the primary to a focus behind the
primary. The CC is defined by the curvature of the mirrors to be a parabolic primary and a strong
hyperbolic secondary. By proper choice of mirror curves, the telescope can be made to have zero
spherical aberration. “Spherical aberration occurs when light rays parallel to the optical axis entering a
system come to a focus at different points along the axis”1
. However, the next aberration that is
significant is coma, which “occurs in an oblique bundle of light when the intersection of the rays is not
symmetrical but is shifted with respect to the axis of the bundle”2
. By using a hyperbolic primary and a
hyperbolic secondary, and with proper mirror spacing, both spherical aberration and coma can be
minimized.
Again, this is a reflecting telescope design with no refractive elements. Refractive elements are to be
avoided if chromatic aberration is to be minimized. Chromatic aberration occurs when different light
wavelengths come to focus at different points, due to the refractive nature of glass. If there is no
refractive element, there is no chromatic aberration.

The Ritchey-Chrétien or RC optical design is well known to discerning astrophotographers and is the telescope optical design in many of the leading professional observatories of the world. Meade has taken its f/8 RC optical design to another level by adding a corrector plate to reduce residual astigmatism that is inherent in the traditional optical design. In addition many more design features were added to the RCX400 for the demanding researcher and imaging enthusiast

Series 5000 24mm 2" O.D.
Ultra Wide Angle Eyepiece:
Standard equipment on all RCX400 telescopes, the Series 5000 24mm 2" O.D. Ultra Wide Angle Eyepiece represents the ultimate in eyepiece design and technology delivering extremely high resolution, contrast and full-field sharpness over an astounding 82° apparent field-of-view. Only the highest quality materials were selected to create this extraordinary eyepiece. The designs required several different types of exotic glass in order to achieve the highest level of optical performance.

New Carbon Graphite & Kevlar Tube:
The carbon graphite and Kevlar tube is a unique light-weight, high strength material with ultra-low expansion characteristics that will maintain the spacing between the optics, so that focus settings do not change with outside temperature changes. This is a critical feature to astrophotographers. Instead of forcing a perfectly round shaped tube assembly, the tube is shaped around the mechanisms and drive system of the front focus and collimation assembly, giving the RCX400 its unique look and style.

New Rear and Front Cell Architecture:
The front and back cells of the RCX400 are designed to allow the maximum amount of air-flow around the optics, in order to achieve the quickest "cool down" times. To accelerate cool-down time, a built-in fan on the rear cell can be turned on and off through the AutoStar II handbox. The rear cell additionally incorporates a multi-port panel with 3 USB ports, a port for an autoguider, AutoStar II handbox, illuminated reticle, RS232, and one for future "Smart" accessories.

RCX400 Drive Base:
The multi-port panel of the RCX400 drive base includes a special single High-Speed USB 2.0 input port allowing simultaneous control over the telescope and either the Meade LPI or Deep Sky Imager camera through Meade's AutoStar Suite software. Additionally there are ports for a power cord input, the AutoStar II handbox, a DB-9 auxiliary port, 12v out power port, and RS-232. Additionally the RCX400 includes the familiar on/off switch and LED power light indicator.

New Ultra-Stable Tripod:
Standard equipment for RCX400 10", 12", and 14" telescopes, the patent pending trigger release leg locks of the Ultra-Stable tripod are positioned at the top of the tripod legs for easy access.

It is generally accepted that the Ritchey-Chrétien or Classical RC system is the premiere optical design for medium to large aperture astronomical telescopes. The primary benefit of a Classical RC is the fact that it is an aplanatic design which means it is coma-free. Coma is an optical aberration that causes star images to appear comet like with tails that point away from the center of the field of view. The further from the center, the larger the effect. Fast Newtonians suffer from this aberration the most, followed by other reflecting optical systems of various designs. The Schmidt-Cassegrain or Schmidt-Newtonian design typically has ½ the coma of a Newtonian of the same focal length. The Classical RC design uses a hyperbolic primary mirror and a hyperbolic secondary mirror to create an aplanatic optical system which has no coma. This system produces small round star images all the way to the edge of the field of view.

Meade’s engineering team recognized the advantages of the Classical RC design but explored the possibility of using Meade’s unique engineering and manufacturing expertise to improve on the basic design. The result is the RCX optical system which is also an aplanatic, coma-free design with small round star images to the edge of the field. The RCX design is very similar to the Classical RC and achieves the same benefits by using a hyperbolic secondary with a new advanced front corrector plate and primary mirror that together perform as a hyperbolic primary. This design has several advantages over the Classical RC design.

The RCX eliminates the secondary mirror holder support vanes (spider) that cause diffraction spikes. Because almost all reflecting telescopes produce diffraction spikes, many people are used to seeing them and don’t consider them an aberration. But in reality, they are a large distortion that reduces image contrast, lowers resolution and presents an unrealistic view of the sky to the eye or the astro-imager.

The RCX design reduces the amount of astigmatism that is inherent in the Classical RC design.

The RCX, due to the front corrector plate, is a closed tube design. This keeps the primary optical components protected from dust, moisture and other contaminates that might fall on the optical surfaces of the primary and secondary mirrors.
While the RCX optical system is significantly more expensive to manufacture than a Classical RC, it was chosen because of its superior performance (i.e., no diffractions spikes, reduced astigmatism and closed tube). Due to Meade's years of experience in designing and manufacturing sophisticated corrector plates and optical systems, we are in a position that very few, if any, other companies enjoy. Applying this expertise and Meade's resources, we are able to produce this advanced optical system at a fraction of the price that other companies would have to charge, if they could produce it at all.

Precision GPS Alignment:
Telescope alignment is accomplished automatically using signals from the Global Positioning System (GPS), a satellite system that enables extremely precise communication to the telescope of the observer's latitude and longitude, as well as local time. Integrated True-Level and North electronic sensors in combination with a high-sensitivity Sony GPS receiver located in the left-hand fork arm result in accurate telescope alignment to the sky at the touch of a button: Just press the ENTER button on the Autostar II hand controller and watch as the telescope measures level, points North, and slews at 8°/sec. to its first alignment star. Magnetic declination compensation designed into the telescope software automatically engages during the alignment process.


Precision Encoder-Measured
Digital Focusing:
With a laser aligned primary mirror fixed in position, focusing is performed electronically and digitally by precisely moving the entire front cell in increments as fine as 1/100 of a millimeter. Digital readout of the focus position can be read on the telescope's AutoStar II handbox. There are 4 different focusing speeds from fine to fast. Since the process is accomplished without moving the primary mirror, the entire assembly is virtually free from image shift.

Computer Optimized Internal Baffling: Unlike traditional Schmidt-Cassegrain designs, the primary mirror moves along a baffle tube in order to achieve focus, Meade's RCX400 primary mirror is mounted independent of the baffle tube. This allowed Meade's engineers to take full advantage of the baffle design to create full stray light cut-off performance, in order to produce the maximum contrast. Additionally the secondary baffle, machined of aluminum with its distinctive outer knife-edges further minimizes stray light in the optical path.

Precision Electronic Optical Collimation:
Collimating a Cassegrain telescope has never been easier. RCX400 owners will make precision collimation adjustments to the secondary mirror of the telescope by using the arrow keys of AutoStar II handbox, allowing a single person to simultaneously make adjustments and see the results. In addition, Meade precision collimates the optics at the factory and then sets that position as the default setting. So in the case where one may make a mistake in making a collimation adjustment, the default setting can always be used.

Built-In Dew Heater:
Instead of wrapping a heating element around the telescope's optical tube assembly to send heat through the telescope's front cell to prevent dew from forming on the corrector plate, the RCX400 incorporates a nickel-chromium wire heating element that is in contact with the glass of the corrector plate that quickly, efficiently, and safely sends heat through lens using the lowest power drain possible. With two onboard temperature sensors, one to measure ambient temperature (placed inside the fork arm) and one to measure the temperature of the corrector plate, the RCX400 can be set to have the built-in dew heater keep the corrector plate warmed to a user-defined setting above ambient temperature. By only using the dew heater precisely when needed, battery usage is managed to its optimum. All functions to operate the dew heater are controlled by the AutoStar II handbox.

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