250/1250 Foto-Newton reflector with Quarz mirror and OctoPlus focuser in carbon tube (Carbon-tube made in Germany, assembled in Austria)
Transportgewicht: 18kg (Versandkosten)
EAN Code: 9120069910346
Wien: Vorbestellen möglich
Linz: Vorbestellen möglich
Lager: bitte anfragen!
Woanders billiger? weiter...
With a f/5 primary made of Quarz, which has zero temperature expansion. It keeps its form while cooling, and allows for very fast high magnification observing. With our carbon tubus and extra
rigid Octo60 focuser. Each Lacerta Photonewton is tested individually!
It began as a project to offer a ready optimized Newtonian of affordable
price, but having all necessary properties to deliver best images. It
was developed through constant feedback, and now we have a well
established brand on its own, used by the best and most active
photographers here. Some references are given at the end. Here we
explain the most important improvements we do:
Carbon Tubus - Made in Germany
Carbon is an ideal material for Newton tubes, but there are differences. Our tube maker Klaus Helmerichs
has a long experience in producing lightweight but extremely stiff
tubes, and developed his own techniques. Our tubes have the special
feature to be more thick at the front and rear end, so tube rings from
the shelf can be used. An importat point to save money, but no
compromise on stability.
Velour - no baffles
Baffles can be very effective in
suppressing stry light, but there are certain caveats. Cheap newtonians
from far east tend to use baffles which are not properly calculated, but
just put in in same distances and often let no more light pass than the
primarys diameter. That means first, they introduce vignetting into the
system. Second, they are not working effectively, and third warm air
rising from the primary must enter the light path every time it flows
around a baffles edge. That may cause distortions, as air is not
optically inactive. And fourth, the most important spot for straylight
suppression on a Newtonian is the tube wall opposite of the focuser,
from where reflected light can surpass the secondary and reach the chip
directly. This is not covered at all by these baffles. We are using
black velour to tape the complete inner tube wall, which is especially
effective against strewlight entering in a shallow angle, where normal
black matte paint is working less good. At the same time the contact
between tube wall and air is buffered by the textile, so tube currents
are prevented. And of course, the important spot opposite the focuser is
blackened as well. Before applying, the self-adhesivevelour is being
taped off, so loose particles and fibers are removed.
Of course, the focuser is one main point in
astrophotography. Same story here: Starting with a good and sturdy
R&P focuser from the shelf, we built in ball bearings for the worm
so it can not move back and forth, improving the mechanics. We replaced
the original focuser tube with our own much thicker one, which has steel
inlays for the 8 bearings. The inner diameter of the draw tube is
brought to 50.9mm, so an inserted corrector cannot tilt anymore. The 8
bearings are made adjustable with pull and push screws at 90° angke too,
and that at the same time stabilizes them. While movements are smooth
and friction can be apllied, the draw tube is extremely stiff and cannot
be bent by lateral weight up to 5kg, and out MFOC motofocus can stem a
8kg weight reproducable to 1 micron precision. To fix equipment we have
made a centerlock clamp. So gear is rotatable, but stays on the optical
axis and stability is literally like screwed down. Please consult Octo60 website for more.
a customers comment, too nice to hide it (Bernd Weinzierl):
Tommy, I just love this part !!! Perfect clamping, no tilt at all, no shifting, how could I ever live without it???
Secondary edge and rim blackened, bigger screws and steel plate
both edge and rim of the secondary mirror is blackened. Including
the small chamfer that surrounds the aluminized mirror surface. Total
reflection or no reflection, for best contrast, no straylight introduced
there. The secondarys are glued to the holder, and not in a housing
that may exert stress on the mirror at low temperatures. A secondary
heater is available optionally. The collimation screws are steel, and a
round steel plate beneath them from prevents grooving the secondary
Primary rim blackened:
photographers are very critical, and a little secret to improve star
halos is to mask off a small portion of the primary. That helps in
softening diffraction artefacts from the clamps that secure the primary
in its cell. At the same time it prevents stray light from the the
primarys chamfer and mask off eventual edge zones. That very small
scrifice pays off in practice!
Quality is scrutinized on each individual sample:
Each Lacerta Photonewton
is tested individually, asserting the required position of focus,
mechanical stability, ultimate precise collimation, and of course
optical quality. No lemon optics will survive this tests!
We can deliver tests up to interferometric measurements of the whole system. We do not take this part easy, please refer to the test preparations and measurement
to now unfortunatly available in German only, here is our worlds first
collimation guide for photographic newtonians. How to achieve best
stars up to the corners of your chip:
Newtonian collimation for astro photographers
For best possible star forms do not compromise on the corrector! In a package we offer our 4 lens coma corrector KomakorrF4,
a Wynne style corrector that does not change the focal ratio at all,
and deliver sharp stars across the field. The cheaper 2- lens correctos
of Ross design introduce sperical aberration, and that softens stars not
only in the field but also on axis. Compare yourself, open in two
browser windows and blink back and forth - This comparison is courtesy
to Burkhard K.:
some sample photos:
specifications 10" f/5 Quarz
weight: 13,5kg OTA without tube rings and rail
tube length: 1165mm
focal position over tube: 140mm
secondary diameter: 63mm
100% illuminated field with GPU comacorrector: 15mm
light loss at fullframe edge: 9% (0,1mag)
focuser over primary: 965mm
Mirrors are made of: Quarz
Upgrades and special requirements:
we are open
to do any upgrade on our Newtonians, for example we can offer them with
TRUE 3" Feathertouch focuser and 3" corrector,
but be aware that these two parts alone cost approx. as much as the whole telescope in standard edition.
Adding other special requirements, like secondary heater, or different focal position for an optional reducer, is possible - just ask us.
course our Newtonians are fully usable for visual observation too. The
standard edition is optimized for use with KomakorrF4 corrector, so the
corrector just does not introduce vignetting the primary. You could use
our visual back M48508 and insert your ocular. For compensating different eyepiece focal planes, it is possible to shorten the Octo60 by removing the Octo 12mm extension ring below the center lock, or adding more of those rings.
some customer opinions:
I have the 10" since 25.000km in my car and never needed to recollimate.
You have made a fantastic instrument, I am totally excited. The first comet pics last night were convincing. All you promised was met point for point.