Alluna
Ritchey-Chrétien telescopes are professional telescopes and convince
with outstanding properties. Ideally suited for astrophotography, even
with large CCD cameras, as well as for use in the broad field of astronomical
research. The universal usability, stability and compact design with low
weight still make Alluna Ritchey-Chrétien telescopes the perfect
telescope for schools and public observatories.
Highly accurate optics
in a high quality tube, optimized system accessories and
intelligent control make Alluna Ritchey-Chrétien telescopes to the
reference in this size-class of telescopes. Already today our clients countless installations reliably fulfil their purpose night for night.
Our Ritchey Chrétien telescopes are available in sizes 16", 18", 20" and 24 inches.
Alluna
RC telescopes - some advantages at a glance
|
 |
Highest
production quality
"Made
in Germany" |
|
Reliable
and robust
Mechanics |
|
Precision
optics from Zerodur glassceramic
Made by Alluna |
|
Secondary
mirror focusing |
|
Choose from 4 sizes
16", 18", 20", 24"
|
|
High
instrument load possible
(Optional
up to 40 kg) |
|
Torsionally rigid ALU / Carbon tube |
|
Easy
adjustment and absolute
collimation
stability |
|
Optimized
4" accessories
for astrophotographers |
|
Robotic main
mirror cover |
|
Telescope-Control-System
with API Application Programming Interface |
|
ASCOM compatible |
|
5-YEAR-Extended Warranty
included
|
|
remotely
controlled |
Alluna Optics
has been known for years for excellent optics for reflecting telescopes.
In our own manufacturing facility every single RC mirror set is manufactured
with utmost precision and care as well as quality inspection. We use only
optics from our own production. Only in this way have we been able to ensure
a consistently high optical and mechanical quality of our telescopes for
years. With delivery, each telescope comes with a detailed test certificate
including all necessary optical information. We mainly use Zerodur as mirror material, a glass ceramic which is also used in the largest telescopes in the world. Zerodur has practically no expansion with temperature changes, the thermal expansion coefficient is e.g. 27 times lower than that of quartz glass / fused silica.
When properly
installed, the Ritchey-Chrétien system is known for its large, coma-free
field. Astrophotographers can use our telescopes for making photographs
without visible loss of a large field and without corrective lenses. For
CCD cameras in full size or greater, we offer a double-lens 4 inch AFFC
(Alluna Flat Field Corrector). With this corrector a photographic plane,
a free field can be used of 65 mm diameter free of coma and astigmatism.
The corrector is optimized from 404 - 1050 nm. The standard coating of both mirrors is a multilayer aluminum coating with 94% reflection in the visible range. With our three-lens
4 inch AFFR (Alluna Flat Field Reducer), the focal length is reduced from
f8.0 to f6,0. The field free of vignetting with this reducer is 60 mm
in diameter and thus still far larger than required for full-frame. More
about our RC correctors
 A
Cassegrain telescope requires not only perfect functionality but also the greatest
precision in all mechanical components for proper operation.
Our telescopes meet all the requirements
of high-quality telescopes this size and are regarded as a world reference
point. You will not find mirror shifting under load variations, collimation
problems, wobbly components or protruding screws in our telescopes. Heavy
CCD cameras, for example, do not cause a problem. If required, we can build
your OTA so that a 50 kg instrument load at the output is possible for
very heavy accessories like spectrometers or heavy cameras.
The optical performance, precision,
reliability, and the demand for the highest quality are not left to chance
in Alluna Ritchey-Chrétien telescopes. We use specifically for construction
and design of our systems, the indispensable support of state-of-the-art
3D CAD. Complex parts and assemblies are modelled exactly as required and
assembled virtually in advance. Thus, all parts can be optimized in advance,
for example, for weight, stability and expansion behaviour. Using the most
modern CNC machines for manufacturing, all parts are made from solid aluminium
material in an elaborate honeycomb structure. Only in this way can an RC
telescope function demonstrating optimal stiffness, resilience and collimation
stability in conjunction with low weight.
 |
Image on the left. Three
CCD cameras with massive distribution block, total weight 45 kg connected
to an Alluna RC20 telescope output.
No problem for our RC telescopes!
Everything is fixed, nothing can shake, the telescope collimation remains
rigid and collimation stable. Read more in blog |
| . |
|
 |
Image on the left. Alluna
RC with carbon fibre tube.
Our Carbon Tube Ritchey-Chrétien
telescopes are suitable for use under extreme conditions when an open truss
system is not suitable. More about Alluna Carbon telescopes |
 Take care of your astro-images or research, the Alluna Telescope-Control-System (TCS) will take care of the basic functions on the main telescope.
Firstly, the cooling of the optical tube and the primary mirror and secondly, focusing of the secondary mirror. The optional robotic main mirror cover, the instruments rotator, as well as the secondary mirror heater can be operated via the controller.
In Climate mode, you get accurate temperature information, control of the fan is fully automatic depending on the current delta between ambient and main mirror temperature. In Focus mode, the current focal position is shown on a large display in digits, and the current back focus is specified from the back plate in millimeters. The focusing accuracy is at a resolution of 2240 digits per 1 mm, which corresponds to 0.446 µm/digit on the secondary mirror or 0.0035 mm on the CCD chip.
With the GoTo function, you can automatically navigate to stored focal positions quickly and accurately. The Alluna Telescope Control System has an additional CCD Instrument Rotator mode. The precision instrument rotator has a positioning accuracy of 0.01 degrees, rotational speed 5 degrees / second. This includes all the features that are important for a comfortable and precise control of this extremely useful and necessary astrophotographer’s tool.
The method of control is your choice! The TCS can be used with a PC/Notebook, autonomously with the optional touch screen hand controller or remotely. With API "Application Programming Interface" an extensive syntax is available, with which you can easily integrate all TCS functions in your own application. The ASCOM compatibility ensures trouble-free interaction with all major astronomy programs.
A detailed explanation about the functions of the Telescope Control System TCS can be obtained under the
corresponding TCS product page.
Overview of RC telescopes
technical data
|
| . |
Alluna RC16
|
Alluna RC18
|
Alluna RC20
|
Alluna RC24
|
| Primary mirror
Ø |
415 mm
|
465 mm
|
515 mm
|
610 mm
|
| Optical Ø |
405 mm
|
455 mm
|
505 mm
|
600 mm
|
| Main mirror ap. |
f 3,0
|
f 3,0
|
f 3,0
|
f 3,0
|
| System ap. |
f 8,0
|
f 8,0
|
f 8,0
|
f 8,0
|
| Secondary mirror
Ø |
160
|
175
|
190
|
222
|
| Obstruction |
44%
|
44%
|
43%
|
43%
|
| Back Focus /mirror |
355 mm
|
355 mm
|
355 mm
|
355 mm
|
| Back Focus /backplate |
250 mm |
245 mm |
240 mm |
230 mm |
| Weight |
52 kg
|
62 kg
|
79 kg
|
125 kg
|
| Telescope-control-System |
TCS-2 |
TCS-2 |
TCS-2 |
TCS-2 |
| Extended Warranty |
yes 5-Year |
yes 5-Year |
yes 5-Year |
yes 5-Year |
| . |
|
|
|
|
| optional available: |
|
|
|
|
4" RC Field Corrector
|
yes
|
yes
|
yes
|
yes
|
4" RC Reducer 0,74x
f/8,0 to f/6,0 |
yes
|
yes
|
yes
|
yes
|
| additional lateral mounting plate |
yes |
yes |
yes |
yes |
| Instrument-Rotator |
yes |
yes |
yes |
yes |
| Robotic DustCover |
yes |
yes |
yes |
yes |
|
|
.
|
1
2
2