Ritchey-Chrétien
Telescopes
| Alluna
Ritchey-Chrétien telescopes with two hyperbolic mirrors convince
with their outstanding universal properties. The compact design along with
low weight, colour purity, planar field free of coma and astigmatism with
65 mm in diameter. Smallest possible spot diameter up to the outer edges
of the image field. All components, optics, mechanics and software meet
highest quality standards. |
The
robust CNC machined Aluminium Carbon Truss tube guarantees high adjustment
stability and easy handling. All major tube components feature a complex
honeycomb pocket structure, allowing us to realise an extremely lightweight
yet higly stable tube. |
| Since the Ritchey-Chrétien
is a system with two mirrors, it has no chromatic aberration, hence it
can be used throughout the entire spectrum from ultraviolet to the long-wave
infrared (100nm-12mu). Through the excellent image quality, on-and off-axis,
the large usable field and the versatility of a Ritchey-Chrétien
system are our RC-telescopes are particularly suitable for being applied
in astrophotography and the wide range of astronomical research. The RC
telescopes are also a great visual instrument and thus are also well suitable
for observatories serving the public.
Despite the high quality
and the complete assembly of all components in Germany, we have succeeded
to keep the price of our Ritchey-Chrétien Telescopes equal or even
less compared with other significantly simpler telescope systems of equal
size. Moreover, a Alluna Ritchey Chrétien telescope already comes
with important components such as the Telescope Control System. The focussing
of the secondary mirror that is included in delivery allows to connect
the 100 mm exit at the back side fixed and absolutely shake/bending-free
with the telescope. Contrary to simple telesopes using a draw tube at the
exit no deflexion or shaky connections through heavy weight of, for example
a heavy CCD camera may occur. |
| Alluna
RC Optics |
The
optical design was developed exclusively for Alluna Optics by one of the
best European specialists in the field of telescope optics. Every single
mirror set is being manufactured and tested with extreme precision and
care in our own production. As a matter of course we deliver a detailed
certificate with the original interferogram with every telescope. Using
the double lens Alluna Flat Field Corrector (AFFC) allow to use a planar
field of 65 mm in diameter free of koma and astigmatism for photographic
purposes. The usual lens size of 400 to 700 nm has been increased to
400 - 900 nm. You will receive an outstanding and future-proof optics perfectly
suitable for bigger 45x45 mm CCD chips of the newest generation, too. Looking
through our RC telescopes is visually impressive, the sharp and come-free
picture will convince you and your visitors.
For focal length reduction
is a 4 Inch .74 x reducer-corrector (AFFR) available. The focal length is reduced from f8,0 to f6,0. The field is fully corrected of 60 mm
Spot diagrams composite
486-656 nm sample at 20 inches Alluna RC with AFFC
|
| Alluna
RC Truss OTA |
The optical performance,
the accuracy, reliability, and the demand for highest quality aren't left
to chance with Alluna Ritchey-Chrétien telescopes!
As it is common in many
other technical areas, too, we make of the indispensable support of modern
CAD specifically optimised for construction and design of our systems.
Complex single components and sub-assemblies are modelled exactly upon
the requirements and assembled virtually before production.
OTA modeling in CAD |
Finite element analysis
Supporting components |
Thus, all parts can be optimised
in advance with regard to weight, stability and expansion behaviour. The
comprehensive FEA (Finite element analysis) additionally helps to analyse
all supporting parts by means of a stress simulation, thus being an important
tool for a target-oriented construction.
Construction data derived
from CAD are “directly” transmitted to the currently most advanced CNC
production machines and the precision elements required for our OTAs are
produced with a precision of a hundredth of a millimeter. All parts are
matching and fit to each other down to the last detail. |
| Alluna
Telescope Control System TCS |
 You
may cooncentrate on your astro shots or research work while the Telescope
Control System (TCS) will take care of the basic functions of your telescope.
On the one hand climatisation ot the optical tube and the main mirror,
on the other hande focussing of the optics.
The climate mode also provides
exact temperature data. Controlling the fans is fully automated, depending
on the current delta between surrounding temperature and main mirror temperature.
The focus mode displays the current focus position in  digits,
mm or inches on a large-sized display. The GoTo function allows you to
approach pre-set focus positions fast and precise. The so-called focus
drift is automatically compensated. The secondary focuser features a resolution
of 5904 digits per 1 mm, corresponding to a mathematical step width of
rounded 0.17µ! In addition, the Telescope Control System features
the so-called CCD rotator mode including all functions required for
a comfortably and precisely controlling this extremely helpful tool for
all astrofotographers. For a detailed explanation of all Telescope
Control System functions, please refer to the corresponding product page. |
| Basic
information about Alluna RC |
-
Available sizes: 16 / 18 / 20 / 24 inches f 8,0 system
-
Real Ritchey-Chrétien telescope with two hyperbolic mirrors
-
Quality Alluna optics selectable Pyrex or glass ceramics Zerodur
-
Optics interferometrically tested and certified min. 1/20 wave RMS / 632nm
-
High-quality aluminium coating 94% with SIO protective layer
-
AFFC 4" Field corrector - flattened, coma/astigmatism-free field of 65 mm
diameter, annealed 400-900 nm
-
AFFR 4" Reducer Corrector x.74, coma/astigmatism-free field of 65 mm
diameter, annealed 400-700 nm
-
Future-proof, also suitable for the bigger CCD chips of the new generation
-
max. spot radius: 1.5 micron rms 25 mm off-axis / 486-656 nm (AFFC)
-
Applicable from ultraviolet to infrared
-
Large-sized back focus area of 355 mm
-
weight-reduced, honeycomb structure, warp-resistant carbon / aluminium CNC truss tube
-
easy adjustment and long-term adjustment stability Manual
-
vignetting-free through large 4-inch connection and optimized Buffle System
-
Secondary mirror focussing with position memory, automatic focus positioning,
automatic focus-drift compensation
-
Temperature measurement directly at the mirror
-
OneView temperature monitor, automatic fan control
-
Telescope control system for automatically monitoring focus temperature,
robotic Dust Cover, fan and CCD image field
rotator on your PC Info
-
Ready for image field rotator Info
-
Only one USB cable for controlling the entire telescope, ASCOM interface
-
absolutely high-quality optics, mechanics and software; Complete manufacturing
" Made in Germany " ! |
| Technical
Data Alluna Ritchey Chrétien Teleskope |
| . |
Alluna RC 16
|
Alluna RC 18
|
Alluna RC 20
|
Alluna RC 24
|
| Main
Mirror |
16 Inch / 415 mm
|
18 Inch / 465 mm
|
20 Inch / 515 mm
|
24 Inch / 610 mm
|
| Main
Mirror Aperture |
f3,0
|
f3,0
|
f3,0
|
f3,0
|
| System
Aperture |
f8,0
|
f8,0
|
f8,0
|
f8,0
|
| Sekundär
Mirror |
158 mm
|
166 mm
|
185 mm
|
215 mm
|
| Obstruction |
38
|
36
|
36
|
35
|
| Back
Focus |
355 mm
|
355 mm
|
355 mm
|
355 mm
|
| Weight |
41 kg
|
58 kg
|
74 kg
|
120 kg
|
| . |
|
|
|
|
| Correctoren: |
|
|
|
|
RC
Field Corrector f 8,0
corrected field: 65 mm |
2 lenses 95 mm
M100x1
|
2 lenses 95 mm
M100x1
|
2 lenses 95 mm
M100x1
|
2 lenses 95 mm
M100x1
|
RC
Reducer f 6,0
corrected field: 60 mm |
3 lenses 93 mm
M100x1
|
3 lenses 93 mm
M100x1
|
3 lenses 93 mm
M100x1
|
3 lenses 93 mm
M100x1
|
|
| References |
| are available for business
outside of Germany |
| Prices
in EURO without 19% German VAT plus shipping and packing |
| Delivery
times to be agreed individually |
| trading
conditions |
|
Alluna Ritchey Chretien
Telescope
in motion
Ritchey
Chrétien or Dall Kirkham
...
the differences
Easy
collimation of a Alluna
Ritchey
Chrétien Telescope
Alluna Optics RC16 on Paramount ME - observatory Taiwan
Alluna Optics RC18 Ritchey Chrétien Telescope / Germany
Alluna Optics RC16 on Astro Physics 1200GTO / Germany
Alluna Optics RC20 at installation on ASA DDM160 - Atatürk University Erzurum / Turkey
Alluna Optics Ritchey Chrétien Telescopes
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