The 8" Ritchey-Chrétien is the perfect telescope for astrophotography, but it is also suitable for visual observation.
♦ Aperture 8" / 203 mm - focal length 1624 mm - focal ratio f/8
♦ Hyperbolic primary and secondary mirror for significantly enhanced sharpness on the optical axis and a large well-corrected field for astrophotography
♦ Both mirrors made of fused silica for stable focus position
♦ 99% highly-reflective coating on main and secondary mirror for an even brighter image and more contrast
♦ Quicker cooling down thanks to open construction and primary mirror ventilation
♦ Two Vixen style dovetail bars supplied - ideal for accessories like guiding scopes or a piggyback camera mount
♦ High-quality 2" dual speed MONORAIL focuser with 2" / 1.25" reduction adapter - motor focuser optionally available
♦ Spacer sleeves for optimal focus position behind the focuser are included.
♦ RC correctors for larger sensors from APS-C upwards are optionally available
♦ Optional: CCD47 - 0.67x focal length reduction for photography our recommendation for shorter exposure times
Most large professional telescope are constructed according to the RC principle. Until recently, these telescopes were unaffordable for amateurs. Our RC telescopes are primarily aimed to amateur astronomers with photographic interest. These telescopes are perfectly suited for high-resolution astrophotography. Of course, an RC can also be used for visual observation. Here, the large corrected field of view is noticeable, too. In total, the stars are sharper than, for example, in a Schmidt-Cassegrain.
The Monorail focuser combines the ease of movement of a Crayford focuser with the stiffness of a rack-and-pinion focuser. Thus astrophotography becomes a success.
♦ Massive stainless steel bar instead of small ball bearings for more stiffness.
♦ No tilting anymore when locking the drawtube.
♦ 360° rotation for optimal object alignment
♦ Female M69x1 thread for threaded adaptions
♦ 2" and 1.25" compression rings for push adaptions
♦ 1:10 dual speed for accurate focusing
♦ Motor focus can easily retrofitted
♦ Lined scale for quick retrieving of the focus.
♦ Easy operation
Quartz glass does not change its dimensions if temperature changes. When the temperature changes slowly during an exposure, other mirror substrates, like Pyrex, tend to a deformation of the mirror and thus to a shift of the focus. This problem does not exist for mirrors of quartz glass. Thus the focus is better maintained which is very important for long exposures. Both mirrors are coated with 99% reflectivity. The image is obviously brighter than the one of telescopes with only 90% or 94% reflection layer.
Better and sharper astrophotos without corrector with shorter exposure times.
This is exactly what this RC telescope allows you to do with astro cameras and SLRs up to APS-C sensors. As a pure mirror system, you can even use the infrared light. You can achieve up to 25% shorter exposure times and sharper imaging than, for example, through a comparable Schmidt-Cassegrain telescope. For the use of a reflex camera without focal length reduction you need the 50mm and the 25mm extension between focuser and telescope.
The generous back focus also allows the connection of correctors, which we recommend from the use of full-frame sensors. You can also connect a focal length reducer, thus further increasing the light intensity of the RC.
Maksutovs and Schmidt-Cassegrains have spherical mirrors and need correctors for making a large field usable. With Schmidt-Cassegrains, you can see the aberrations in the field even when working visually. Most times, Maksutov-Cassegrains are so slow that they are not suitable for astrophotography. RC telescopes have hyperbolical primary and secondary mirrors. They are more difficult to manufacture, but offer a significantly sharper field with less aberrations throughout the field.
The CCD reducer improves the focal ratio from f/8 to f/5.36, thus reducing the exposure time to less than 50%. With this, you can capture dim nebulae and galaxies with moderate exposure times.
|Type of build||Ritchey-Chretien|
|Focal length (mm)||1624|
|Aperture ratio (f/)||8|
|Limit value (mag)||13,3|
|Light gathering capacity||840|
|Max. useful magnification||406|
|Tube weight (kg)||7,5|
|Tube length (mm)||580|
|tube diameter (mm)||230|
|Tube construction||Full tube|
|Main mirror´s construction||hyperbolic|
|Secondary mirror material||Quartz|
|Secondary mirror obstruction||18|
|Primary mirror - Material||Quartz|
|Secondary mirror diameter (mm)||85|
|Type of build||Monorail|
|Connection ( to eyepiece)||2|
|Gear reduction||1:10 Fine movement|
|Mounting type||no mount|
|Type of build||OTA|
Area of application
|Moon & Planets||yes|
|Nebulae & galaxies||yes|