Information
Glass
Coating
Quality Examination
Quality Warranty
Alluna Ritchey Chretien Telescopes
Alluna Newtonian Astrograph Telescopes
Info: Ritchey-Chretien
or Dall Kirkham Telescope?
Info: Easy collimation
of a Alluna Ritchey Chrétien Telescope
| Intoduction |
|
| No
matter whether you need a parabolic, hyperbolic, or spherical mirror. At
Alluna Optics you will receive the suitable optices manufactured for highest
demands and exactly fitting to your telescope and your specific application.
We manufacture primary mirrors and complete Ritchey-Chrétien Cassegrain
systems of highest accuracy and surface smoothness. Our lenses are known
for their high quality. Sharp star images, high resolution at highest contrast
characterise our primary mirrors and secondary mirrors. Our clients
are manufacturers of premium telescopes, public observatories, research
institutions and ambitious amateur astronomers who want to be sure to have
a perfect optics. Our customers include, for example, Germany's national
research center for aeronautics and space DLR, the Bern Physics Institute
Space research & planetology, the International Amateur Observatory
IAS and many more. |
We
produce large-sized single optics for industry, research and technology,
for example for striation optics, LIDAR telescopes, collimators, laser
technology and other applications..
Alluna
Ritchey Chrétien and Newtonian astrographs are extremely high-quality,
durable and value conserving telescopes. Know-how, experience, best materials
as well as most advanced construction/manufacturing processes provide for
top class telescopes "Made in Germany". |
| Glass |
Producing
high-quality telescope mirrors requires high-quality glass. Mostly we use
"Pyrex ® No. 7740 fine annealed and precision annealed " for the smaller
sizes. Since the production of Pyrex was stopped we also use Suprax or
Supremax from Schott as replacement material.
For
larger mirrors and for particularly high-quality applications we use glass
ceramic Zerodur. Glass ceramics offer the advantage of a lower thermal
expansion coefficient of about 0.1 × 10-6 1 / K. Hence it shows virtually
no expansion in case of temperature changes.
We
choose the thickness of the glass in a way that no surface deflexion will
occur under normal, appropriate storing conditions. |
 |
20" Pyrex Cassegrain f2,5 |
24-inch glass-ceramic mirror |
|
| Coating |
| We
offer aluminuim coating with a reflection of 94% as standard coating, whereas
the actual reflection in fact is higher than 94% throughout almost the
entire visible wavelength range. For special applications we also offer
other coatings such as silver or gold for the IR range. As a service
feature we offer cleaning and a new coating of telescope mirrors. |
| Quality
Examination |
A perfect shape and, at
the same time, a very smooth surface are the characteristics of all Alluna
telescope mirrors.
Each mirror is calibrated
by interferometry and, depending on the mirror size, up to 10,000 points
on the whole surface are analysed per software. For that purpose we use
to the so-called compensation measurement also known as Ross Null test.
Mirrors and RC systems up to a size of 24 inches (610 mm) diameter are
calibrated in autocollimation against a high-precision flat mirror.
Since we do not rely on
one test only, we also use other tests such as Foucault, Ronchi, the phase-contrast
test and others.
WaveFront Chart
|
Alluna 25 Inch f3, 8 Mirror
Ronchi recording directly
at the star with a 26 lines
/ millimeter Grid !
|
Ronchi in Autokollimation
10L/mm
|
Certificat Mirror
|
In case of the moon, the
planets, disconnecting of close double stars and some planetary nebulae
you will clearly see the advantages of a smooth surface structure both
visually and photographically. In case of mirror telescopes it is particularly
the smooth surface that significantly contributes to highest contrast and
highest possible resolution. Compare
Yourself |
| Quality
Warranty |
| With a mirror of Alluna
Optics give you one of the best currently available on the market Optics
for the telescope. The production does not occur in a highly possible time
but in the most profit potential optical Quality! We guarantee this and
provide any look with a certificate and the original Interferogram.
The quality of our mirrors
will convince you! For standard parabolic mirrors we guarantee surface
accuracy better than 1/30 wave RMS at 632nm. For Ritchey Chretien systems,
we guarantee a surface accuracy of 1/25 wave RMS / 632nm. Each Alluna mirror
has a very smooth surface that is achieved by hardly any other manufacturer.
Various test procedures guarantee consistent high quality.
20 inches Ritchey-Chrétien
Telescope |
30 inches parabolic Astro
Sitall mirror |
|
| Alluna
Ritchey Chretien Telescopes |
Our Ritchey Chretien telescopes
are real RC systems with a hyperbolic primary mirror and a hyperbolic secondary
mirror. The optical design was developed for Alluna Optics by one of the
best European specialists in this field. Every single mirror set is being
manufactured and tested with extreme precision and care in our own production.
CNC manufacturing of tube
Components
Upon developing the high-end
RC OTA we have made no compromises. Precision and reliability were made
the most impartant target during development and construction. All parts
were optimised in advance with regards to weight, stability and expansion
behaviour. All components for the carbon truss tube are made of special
high-quality aluminium alloys and manufactured on most advanced CNC machines.
With this procedure we achieve a very lightweight yet extremely stable
and warp-resistant overall construction by means of a complex honeycomb-pocket
structure. The accuracy of the milled aluminium parts lies at about 1/100
mm up to the 24-inches OTA.
more
about our Ritchey Chretien Telescopes
|
| Alluna
Newtonian Astrograph |
Same as the Ritchey Chretien
telescopes our Newtonian Astrograph telescopes are also manufactured from
the best material with most advanced methods. With every telescope you
will receive a masterpiece of mechanics as well as the guarantee for a
perfect optics. The same honeycomb pocket structure is applied for a light
but highly stable and warp-resistant truss tube. All components are manufactured
directly in our production plant or at partner companies. Only in case
of the 3.5 inches feather touch draw tube we use am external product that
is well proven in practice.
more
about our Newtonian Astrograph Telescopes
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