New Telescope: Clave Clavius 166
Vincent
(Europe). The Clave Clavius 166 is a compact telescope (1.8ft long),
and quite light (10.6 lbs).
Apperture is 160mm (6.3in)
Focal Length is 1,072mm (42.2in)
Focal ratio is 6.7
Central obstruction 24% (5.7% in term of surface)
Optically it's not a Cassegrain, nor a Dall-Kirkham, a
Pressmann-Camichel, a Ritchey-Chretien, a Schmidt Cassegrain or a
Maksutov Cassegrain. Its ancestor is the Dilworth, and its cousin the
Buchroeder. Basically, the Clavius 166 is a fully catadioptric
telescope concisting of a spherical primary, a Mangin secondary, and a
six-lense optical relay in the central baffle.
This telescope was tested in the last issue of the french amateur
monthly "Ciel & Espace". Mechanically, the OTA is labelled "a
benchmark". Optically it's diffraction limited over the field and as
good as a the very best 5in APOs, on and off axis.
However, there's one drawback: the full light field is limited to 1°,
period. Outside of this field, illumination is *zero*.
The telescope is sold as OTA, with a 8x50 finderscope and a Clave
diagonal.
Price is EURO 2,590 / US$ 2,400
A 250mm (9.8in) f/5.7 of the same optical design is planned.
Pros:
Light
Compact
Optically and mechanically beyond reproach
Performs like a 5in APO on and off axis
Cons:
Field limited to 1°
If anyone is interested, I will keep this group posted as soon as an
independent review is published.
Best regards,
Vincent.
Gert Weber
> A new telescope is now available on this side of the atlantic
> (Europe). The Clave Clavius 166 is a compact telescope (1.8ft long),
> and quite light (10.6 lbs).
I live on "this" side of the Atlantic (Germany) and am really
interested in a scope as described!
Is there anyone in Germany who sells this scope or what is the french
adress (with someone speaking/writing english or german, because my
french is VERY bad ;-)
> Apperture is 160mm (6.3in)
> Focal Length is 1,072mm (42.2in)
> Focal ratio is 6.7
> Central obstruction 24% (5.7% in term of surface)
> This telescope was tested in the last issue of the french amateur
> monthly "Ciel & Espace". Mechanically, the OTA is labelled "a
> benchmark". Optically it's diffraction limited over the field and as
> good as a the very best 5in APOs, on and off axis.
>
> However, there's one drawback: the full light field is limited to 1°,
> period. Outside of this field, illumination is *zero*.
In planetary use this is mostly no problem and moon and sun will fit!
> The telescope is sold as OTA, with a 8x50 finderscope and a Clave
> diagonal.
>
> Price is EURO 2,590 / US$ 2,400
> If anyone is interested, I will keep this group posted as soon as an
> independent review is published.
Not cheap, but if it is really like a 5in Apo its a bargain!
--
Dark Skies!
Gert
gert....@netcologne.de
Vincent
> Hi,
> I live on "this" side of the Atlantic (Germany) and am really
> interested in a scope as described!
> Is there anyone in Germany who sells this scope or what is the french
> adress (with someone speaking/writing english or german, because my
> french is VERY bad ;-)
phone +33 1 69 59 29 00 Fax: +33 1 69 59 29 01
I don't know whether they speak english or not. It is better to send a fax first.
Better sky.
Vincent
Jon
telescope? I did a search on Google, and found nothing.
Jon
Vincent...@hotmail.com (Vincent) wrote in message news:<d18c81d7.02052...@posting.google.com>...
Vincent
> This is interesting. Where can I find more information about this
> telescope? I did a search on Google, and found nothing.
>
> Jon
I am not surprised.
if you want to find something (very little in fact) check
www.kinoptik.com (Clave is now a part of Kinoptik). It's in french,
not updated and quite useless. There was a thread about this telescope
on the ATM pages (check for the keyword "Paramythioti").
I just add a "lengthy" expostion of my impressions and a few
explanations which I gathered from the people who designed the Clavius
166 and from the test of Ciel & Espace.
I discovered the existence of this telescope a few months ago when it
was just a rumor: it generated "animated" discussions on several
french lists (check www.astrosurf.com under forum; of course, that's
in french). Several persons expressed doubts about the optical formula
(basically: "There's no innovation, it's a Dilworth, or a Buchroeder
and none ever worked properly"). I admit this was a big gamble for
Clave as indeed no relay telescope ever worked properly. I was very
suspicious with all those lenses in the optical relay.
The Clavius 166 has been made available only recently in France and I
was able to look at Jupiter during a star party in early May. Seeing
conditions were far from excellent. But I must admit that the
telescope performed very, very, very well, at least as far as color
correction is considered (I wasn't able to see any chromatic
aberration). Mechanically the OTA is perfect or damn close. The
focuser is a of the Crayford type, ultra smooth and accurate. The
secondary support is of a truly fine design, especially the
stress-less secondary mirror cell (no matter how brutal you are with
the collimation screws, no stess will be transmited to the secondary
mirror): the best part is that the collimation is *very* stable as the
scope I saw in this star party was carried in a van on a mountain road
far better suited for 4WDs and wasn't re-collimated before I had a
look. The 8x50 finderscope is mounted on six padded screws, but the
nice part is that you can remove it from the OTA, and put it back on
without losing alignement. The OTA is made out of carbon fiber and
light alloys. A nice feature is that the Clavius 166 was designed to
be used with a binoviewer without the need of a barlow lense.
One nitpick thought: The crosshair of the finderscope is a little too
thick (well I had to find something! If you really want to have a good
finderscope, I know where to find a Clave finderscope, the very same
which are mounted on the Pic du Midi smaller telescopes, but for the
same price you will buy a FS60 OTA)
Several owners have said that the telescope generates very little if
no internal turbulence and that images were without any trace of
chromatic aberration. According to the test of Ciel & Espace, high
magnifications views of the Moon and Jupiter were called "impressive"
and "full of constrast" (low obstruction and good optics at work
here). Just to put things into perspective, Ciel & Espace in a
previous issue gave 3 out of 10 to a C8 as far as planetary images are
concerned (this generated heated debates until an independant test
could be done which revealed that this C8 simply was a good Schmidt
Cassegrain, that is, far from perfect per definition...) and gives 9
out of 10 to the Clavius 166. For deep sky objects, the ratings are
just as impressive. A test on Ikeya-Zhang showed 10th magnitude stars
through the comet tail, only 20-30 arcseconds from the comet's head.
If I had ordered this scope, here are the EPs I would have chosen:
25mm Orthoscopic (UO, Zeiss, etc to have a 1° field at low
magnification.)
13mm Nagler (1° field with a magnification of 82x)
10mm, 8mm, 6mm (Ortho, Plössls, Radians, etc.)
x2 barlow
In my opinion, it should be completed nicely with a 80mm f/5.6
Astronomix gel Spaced triplet APO for wide field imaging and the price
of the complete system will fall short of the price of a 5.1in
Astrophysics by $1,000. For less than the price of the 5.1 AP, you
will get the Clavius 166, plus a 100mm f/6.3 Astronomix gel spaced
triplet APO + field corrector (7°+ flat field) which is really compact
(less than 500mm long) and lightweight.
Anyway, I will wait until an independent test was posted somewhere
(most likely in french). If you are interested, I shall translate it
and post it to sci.astro.amateur.
That's for the Clavius 166.
Cloudless Sky to all
Vincent