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ALEPH: Astronomy Precision Instruments & Technologies |
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Home > Intro > Prodotti e Servizi > Riflettori |
Home > Intro > Products & Services > Riflettori |
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Riflettori Astronomy Technologies |
Astronomy Technologied Reflecting Telescopes |
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Ritchey-Chretiénne - astrograph |
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Dobson 16" Astronomy Technologies |
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Un Dobson di grande diametro con struttura truss rail (bracci della truss a sezione trapezoidale) che velocizza ulteriormente il montaggio e fornisce massima rigidità all'assieme.
Movimenti su suppofrti in metallo con regolazione fine del bilanciamento. Focheggiatore Crayford 2" con manovra a riduzione micrometrica 1:10. Cercatore ottico 8x50mm (disponibile una di due versioni: a visione diretta o a 90° con visione raddrizztata) Collimatore laser per una veloce messa a punto delle ottiche. Oculari: 2" 30mm a 5 elementi e 9mm Ploessl in dotazione. Otticche con lavorazione ad almeno 1/6 di lambda P-V sul fronte d'onda (1/12 di lambda sulla superficie ottica). Primario con pecetta centrale preinstallata per la collimazione.
Supporto primario: cella in alluminio con primario supportato su 18 punti flottanti. Ventilazione forzata.
Movimenti: in altezza su cuscinetti a sfera sigillati: nessuna parte a frizione e attrito azerato che viene regolato sall'istante tramite le manopole per definire i,lperfetto stato di frizione necessario al miglior bilanciamento per l'angolo di altezza e gl iaccessori montati (oculari e/o cercatori). Il movimento i nazimut avviene su cuscinetto Lazy a rullini: nessuna parte a strusciamento e assoluto abbattimento degli attriti.
La nota qualità ottica e meccanica AT per un ostrumento trasportabile, di veloce montaggio, con soluzioni costruttive all'altezza della cura per il dettaglio della stessa AT. L'ottica di qualità e la grande capacità di raccolta luce rendono questo strumento un eccellente performer perl'osservatore visualista esigente e per l'amatore avanzato, il tutto ad un prezzo concorreinziale.
Contattateci per conoscere la nostra migliore offerta |
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This 16" Astro-Tech Dobsonian reflector has:
• 1/12th wave
BK-7 optics Like all Dobsonian reflectors, this very complete 16" Astro-Tech truss-tube Dob gives you more light-gathering for your dollar than any other telescope type. Its very large 16" aperture gathers four times the light of an 8" scope (and almost 3400 times as much as the sharpest dark-adapted eye)! The result? It shows you very faint deep space objects that are simply invisible in smaller scopes. And color is often visible in the brighter nebulas. With a visual limiting magnitude of 15.5, this 16" Astro-Tech is ideal for observing faint nebulas, galaxies, and star clusters from a dark sky site – all the faint fuzzies outside the solar system that fascinate us. Despite its large aperture, the 16" Astro-Tech Dobsonian is easy to get to your favorite observing site, whether that be your own back yard or a dark sky site miles out of town. Unlike a bulky Sonotube or metal tube Dob, you don’t need a van or small truck to transport this big 16" scope to the dark sky sites it needs to perform at its best. The 16" Astro-Tech breaks down into a few compact components that fit into virtually any car trunk or into the back seat of just about any compact car. It weighs only 134 pounds fully assembled. Assemble the AT16D in just a few minutes, with no tools needed, and you’re ready for an evening of fascinating viewing at your favorite dark sky location. The first component is the 14 pound aluminum upper cage containing the diagonal mirror, 2" focuser, and 8 x 50mm right angle erect image finderscope. Second is the 60 pound aluminum mirror tub holding the primary mirror in its 18-point flotation cell. Three light-weight (6 pounds total) but very rigid single strut aluminum truss tubes connect the secondary cage to the mirror tub. They have die-cast brackets with curved notches that mate with projections on the cage and tub rims by means of large hand-tighten knobs, making assembly easy. Finally, there’s the 54 pound laminated particle board base (rocker box) in which the mirror tub sits. With 1/12th wave surface accuracy, the performance of the BK7 optical glass mirrors of the 16" Astro-Tech Dobsonian is guaranteed to be diffraction limited – for sharp high contrast images of nebulas, galaxies, and star clusters. Planetary images are also sharp and crisp, although a neutral density filter is certainly required to allow glare-free observing. The mirrors are overcoated with quartz for long life. Because of its compact individual component sizes and reasonably light component weights, the 16" Astro-Tech can easily be transported and assembled by one dedicated individual, although two people will generally make it easier to assemble aluminum upper cage to the truss tubes. Set-up time is only about 15-20 minutes.
The 16"
Astro-Tech Dobsonian is designed for visual observing only – to show
you as much of the night skies in as much detail as possible. Under
dark skies, color becomes visible to the eye in many nebulas. The
Orion Nebula becomes a glowing blue-green mass of filaments, often
tinged with red and yellow for the keen-eyed observer from a dark
sky site. With a resolving power of 0.29 arc seconds, globular
clusters can often be resolved to their cores in good seeing, with
each cluster becoming a vivid ball of tiny individual stars instead
of a hazy blur. er. |
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Knottings and structure in the arms of the Whirlpool Galaxy become clear. Mighty globular clusters in the distant Andromeda Galaxy begin to reach the threshold of visibility for the exceptionally keen-eyed observer. As with any large aperture telescope, the performance of the 16" Astro-Tech Dobsonian on faint objects will be markedly improved by a dark sky observing site. Light-polluted city and suburban sites are not recommended as the primary observing site with any 16" scope. Such light polluted sites require a light pollution filter to take even limited advantage of its immense light-gathering. While it is in deep space observing of galaxies and nebulas from a dark sky observing site that the 16" Astro-Tech Dobsonian excels, significant planetary and lunar observing is also within its capability. Small details in the atmospheres of Jupiter and Saturn and on the surface of Mars reveal themselves at high powers given suitably good seeing. All you need is steady skies and a neutral density eyepiece filter to cut down the immense brightness of solar system objects seen through this immense “light bucket." Simply-made, but with precision optics, this Astro-Tech 16" Dobsonian reflector will reward you with thousands of bright deep space views and years of trouble-free observing enjoyment.
Type: Newtonian reflector with parabolic primary mirror. Primary mirror: 16" (406mm) diameter, 1800mm focal length, f/4.5 focal ratio. BK-7 optical glass, polished to 1/12th wave accuracy, aluminized and overcoated with a protective layer of silicon dioxide (quartz) for long life. 92% to 94% reflectivity. The mirror is center-spotted to aid in collimation. The mirror comes with a protective molded hard plastic cover that snaps into place to keep dust and debris off the mirror during transport and storage.
Primary mirror cell: Fully adjustable 18-point flotation system metal cell holds the primary mirror. The 18-point floatation system supports the large mirror uniformly, so that it holds its parabolic figure precisely, regardless of the optical tube’s orientation. The open frame of the cell allows the mirror to cool down to ambient temperatures quickly, so you can start observing sooner. Large hand-tighten color-coded collimation and collimation lock knobs make it easy to collimate the primary mirror with no tools required.
Primary mirror cooling fan: A lightweight 4.7" diameter low-vibration cooling fan is built into the mirror cell to assure faster cool-down times. The battery-operated fan is powered by an AA battery pack (batteries not supplied) that plugs into a jack on the mirror cell frame.
Diagonal mirror: BK-7 optical glass, polished to 1/12th wave accuracy, aluminized and overcoated with a protective layer of silicon dioxide (quartz) for long life. 92% to 94% reflectivity.
Diagonal mirror support: Fully adjustable diagonal holder mounted on a low-diffraction four-vane thin spring steel spider.
Focuser: Dual-speed 2" Crayford type, with 1.25" eyepiece adapter. The machined aluminum focuser has dual coarse focusing knobs for smooth and precise image control with either hand. There is a separate 10:1 reduction ratio microfocus knob for ultra-fine focusing at high magnifications. The ribbed focus knobs are easy to operate, even while wearing gloves or mittens in cold weather. A 35mm eyepiece extension tube is standard equipment. Both the 2" eyepiece holder and the 1.25" adapter use non-marring soft brass compression rings to hold eyepieces in place, rather than simple thumbscrews that can scratch your eyepiece barrels.
Two eyepieces: One is a fully multicoated 2" 30mm (60x) 68° field SuperView eyepiece with a wide 1.13° actual field of view that’s two and a quarter times the diameter of the full Moon. The second is a fully multicoated high power 1.25" 9mm (200x) 52° field Plössl.
Eyepiece tray: A standard equipment eyepiece tray attaches to the side of the scope’s altazimuth base. It has cutouts to hold one 2" eyepiece and three 1.25" eyepieces.
Finderscope: 8 x 50mm right angle achromatic design with a built-in image-erecting Amici prism. Images in the finderscope are upright and correctly oriented left to right. The star patterns seen in the finderscope are oriented the same way as they appear on star charts and to your unaided eye to make star-hopping easier. Focuses by loosening the trim ring behind the objective lens cell, screwing the lens cell in or out to focus, and tightening the trim ring to lock in the correct focus.
Finderscope bracket: The 8 x 50mm right angle finderscope mounts in a quick release bracket that slips into a pre-installed metal mounting shoe on the secondary cage to maintain its collimation, even if the finder is removed between observing sessions. The bracket is held in place in the mounting shoe by a single large hand-tighten chrome-plated knob. The bracket has two hand-adjust collimation screws that work in conjunction with a third spring-loaded post in the bracket. This makes collimation faster than the traditional three- or six-screw collimation methods used with conventional finder brackets..
Moon filter: A 1.25" glare-reducing Moon filter is standard, given the immense light-gathering capacity of the 16" optics that would otherwise wash out lunar detail. Laser collimator: A supplied 1.25" battery-operated laser collimator for Newtonian reflectors is standard equipment. It combines with the center-spotted primary mirror to make quick work of collimating the fast focal ratio AT16D in the field using the large no-tool hand-adjust collimation knobs. This Telescope’s Mount . . .
Modified truss
tube Dobsonian mount: Instead of the usual six-tube truss design,
the Astro-Tech 16" Dobsonian uses a less-complex three-strut design.
The altazimuth base and upper (diagonal mirror) cage are joined by
three modified trapezoidal cross-section aluminum struts, rather
than the six tubes used on most conventional Dobs. The modified
trapezoidal struts actually have eight distinct facets, providing
exceptional torsional rigidity (resistance to twisting).
Primary mirror tub: The primary mirror and its cell ride in an aluminum tub with die-cast rims for strength and rigidity. The mirror tub has two combined altitude bearing/clutch/balance system assemblies that slip into cutouts in the sides of the altazimuth base (rocker box).
Altitude ball bearings: Instead of the usual large circular trunnion bearings riding on a few Teflon pads in the semi-circular cutouts in the altazimuth base, the 16" Astro-Tech Dob uses innovative sealed metal ball-bearing systems to provide smooth vertical motion of the optical tube. The aluminum bearing housings fit snugly into cutouts in the sides of the altazimuth base. Because the bearings are sealed systems, the elements cannot affect the smoothness of the Astro-Tech’s vertical motion, as it can when dust and grit get trapped between the exposed trunnions and Teflon pads of conventional Dobsonians and scores the surfaces, as it invariably does. The vertical motion of the Astro-Tech tube is consistently ball-bearing smooth. And the sealed ball-bears will not have to be replaced regularly, as is the case with the Teflon pads of many Dobsonians as windborne grit degrades the Teflon/trunnion interface.
Altitude clutch: Large ribbed clutch knobs are built into the two altitude bearings. A gentle twist on either knob adjusts the amount of friction within the altitude ball-bearing systems. This allows you to keep the diagonal mirror cage from rising or sinking when changing between eyepieces of considerably different weights, as for instance when switching between 1.25" and 2" eyepieces.
Tube balance
system: The altitude bearings of the AT16D are bolted to slotted
plates attached to the mirror tub. This allows the optical tube to
be moved fore and aft in the slots to balance the assembled optical
tube. The altitude bearings have been positioned at the factory to
balance a wide range of eyepiece weights with the occasional help of
the altitude clutch knobs. However, if you have mostly heavy
eyepieces in your observing kit, you may want to adjust the tube
balance to compensate for the tube’s nose-heavy balance.
Altazimuth base (rocker box): The altazimuth base that the mirror tub rides in is crafted of strong, lightweight, and water-resistant laminated particle board. The base is shipped disassembled, but can be put together in about a half an hour using only a Philips-head screwdriver and the supplied hardware and hex-head wrench. The AT16D moves in azimuth on dozens of steel roller bearings riding between two metal plates. Push the scope lightly in any direction and it starts moving at the touch of a finger – smoothly and with no fuss. Stop pushing and it settles down immediately, with no shudder or vibration to mar your viewing experience. Carrying handles are provided to make carrying the 54 pound rocker box easier. The feature illustrations of the AT16D shown below are of the white-finish prototype to make it easier for you to see details, but the production models are finished in black as shown in the images at the top of this page. The Astro-Tech AT16D is a big scope – big in aperture, big in performance, big in value. Easy to transport, easy to assemble, easy to own, and easy to use, it can be your introduction to a universe simply invisible in a smaller scope. And this Astro-Tech can be yours only a few short days after you order it.
16” f/4.5 1/12th wave BK-7 optics; 18-point primary mirror floatation system; three-strut truss-tube design; dual-speed 2” Crayford focuser with 1.25” adapter; ball-bearing altitude motion with clutch; roller-bearing azimuth motion; tube balance system; cooling fan; 8 x 50mm right angle erect-image right-reading finderscope; 2” 30mm SuperView eyepiece; 1.25” 9mm Plössl; laser collimator; eyepiece tray; Moon filt
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Tubi ottici Ritchey-Chretiénne |
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Ritchey-Chretiénne
Diametri: 6", 8"; 10"; 12" e 16" rapporto focale f/9 ottiche in BK7
trattamento in alto vuoto: - sul 6" Aluminum Enhanced di ultima generazione (riflettanza media: 96%) - su 8", 10", 12" e 16" depositi dielettrici su primario e secondario.(riflettanza al 99%).
Lavorazione spinta ad almeno 1/6 di lambda sul fronte d'onda (1/12 sula superficie dell'ottica) sia peril primario che per il secondario. Focheggiatore Crayford 2" con movimento micrometrico 1:10
Il disegno RC è il solo disegno ottico che riesce a correggere le aberrazioni sfericza e comatica impiegando due sole superfici ottiche asferiche e portando lasuperrficie focale in posizione esterna all'assieme meccanico.
La correzione elevata fino a bordo campo con rapoporti focali moderatamante lunghi fa di questi gli strumenti d'elezione per l'imaging del profondo cielo con grande fattore di scala e lo schema tipoicamente implementato negli strumenti da osservatorio.
Versioni 6", 8", 10" e 16", tutte con rapporto focale f/9. Meccaniche interamente in alluminio (tubo in alluminio; terminali tubi in fusione; componenti in Alluminio CNC). Focheggiatore 2" Crayford con manovra a riduzione micrometrica 1:10; anelli di serraggio perimetrico su 2" e sul compreso riduttore 1.25". Barra coda di Rondine tipo Vixen (rimovibile); tappi chiusura antipolvere. Diaframmatura multipla antiglare interna.
Gli esemplari da 10" in su sono provvisti di sistema per ventilazione forzata.
Contattateci per conoscere disponibilità e nostra migliore offerta. |
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This AT RC Ritchey-Chrétien astrograph has:
- f/9 true
Ritchey-Chrétien hyperbolic mirror optical design Introducing the Astro-Tech AT6RC, an incredibly affordable Ritchey-Chrétien astrograph that virtually all astrophotographers can afford!
The Astro-Tech AT6RC makes the coma-free imaging of a true Ritchey-Chrétien optical system available to amateur astronomers using webcams, Deep Sky Imager-type cameras, and SBIG ST-7/8/9/10/2000-class CCD cameras. And it does it at a price less than that of even the least-expensive SBIG CCD camera. Featuring a true Ritchey-Chrétien optical system, this incredibly economical Astro-Tech R-C makes you wonder just what those $10,000+ R-Cs have that makes them cost so much. Designed strictly for exceptional imaging, the Astro-Tech AT RC provides the wide coma-free photographic field that astrophotographers crave, but can’t get from conventional reflectors and Schmidt-Cassegrains. Likewise, as a pure two-mirror system, the AT RC is totally free from the spurious color that affects the imaging of all but the most costly apochromatic refractors, and it does it with an aperture that exceeds the light gathering of most apo refractors.
If serious astrophotography is your goal, but the price of most true Ritchey-Chrétien optics has been keeping you from the optical design most modern professional observatories and the Hubble Space Telescope use for their imaging, your wait is over. The Astro-Tech AT RC can bring the world of professional deep space imaging to your backyard observatory at a truly affordable price.
This Astrograph’s Optical System . . . Optical design: true Ritchey-Chrétien Cassegrain-type two-mirror optics, with hyperbolic primary and secondary mirrors. For more details, click on the “optics" icon above.
Primary mirror: Made of BK-7 optical glass. Polished to 1/12th wave or better surface accuracy. Unlike designs that move the primary mirror fore and aft in the optical tube to focus (which can lead to image shift as the mirror position changes) the AT RC primary mirror is fixed to eliminate image shift and focus changes.
Secondary mirror: Made of BK-7 optical glass. Polished to 1/12th wave or better surface accuracy. Mounted in a four-vane spider and fully collimatable using simple standard Schmidt-Cassegrain collimating techniques. Unlike complicated R-C designs that use motors to move the secondary mirror fore and aft to focus, the AT RC secondary mirror is fixed and focusing is done externally.
Enhanced aluminum optical coatings: Both primary and secondary mirrors have enhanced aluminum mirror coatings, overcoated with a protective layer of quartz for long life. Reflectivity is in the 96% range, the same as those $10,000+ R-C scopes.
Optical tube: Aluminum, with die-cast and machined aluminum front and rear cells.
Internal light baffles: Computer optimized primary and secondary baffling. Contrast-enhancing glare-stop baffles in the optical tube, with multiple glare-stop microbaffles in the secondary mirror light shield and primary mirror baffle tube to provide truly dark sky backgrounds during imaging.
Dual-speed Crayford focuser: The non-vignetting focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with a 10:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during critical CCD imaging. All focus knobs are ribbed, so they are easy to operate, even while wearing gloves or mittens in cold weather.
Compression ring eyepiece holders: The focuser drawtube ends in a 2" eyepiece holder that uses a non-marring soft brass compression ring to hold 2" imaging accessories in place. The compression ring won’t scratch the barrel of your accessories as an ordinary thumbscrew can. Also supplied is a 1.25" accessory holder that slips into the 2" compression ring holder to let you use 1.25" imaging accessories. Like the 2" eyepiece holder on the eyepiece holder rotation mechanism, the 1.25" adapter also uses a non-marring soft brass compression ring.
Mounting dovetail: removable Vixen-style dovetail bar running the length of the underside of the optical tube.
Other accessories: A slip-on dust cap is standard.
Two year warranty: As an expression of the confidence Astronomy Technologies has in the quality of their products, the Astro-Tech AT6RC is protected by a two-year limited warranty against flaws in materials and workmanship (shipping case excluded).
Fixed primary mirror with computer optimized primary and secondary baffling: Unlike traditional Cassegrain designs that move the primary mirror fore and aft along the central baffle tube in order to achieve focus (which can lead to image shift as the mirror position is adjusted) each Astro-Tech RC primary mirror is fixed. The Astro-Tech is focused externally by means of a dual-speed 2” Crayford-style focuser on the rear cell, thereby eliminating a Cassegrain’s moving mirror image shift during focusing. Molded field stops are installed along the interior of the optical tube to effectively prevent stray off-axis light from reaching the image plane, resulting in improved contrast. In addition multiple glare-stop microbaffles on the inner surfaces of the primary mirror baffle tube and the secondary mirror light shield further prevent off-axis light from reaching the image plane, resulting in still further improved contrast.
Collimatable secondary mirror: Since the primary mirror of an Astro-Tech RC is fixed in position, only the secondary mirror can (or needs to) be collimated. This makes it easy to keep the Astro-Tech RC optics aligned for peak performance. Collimation adjustments to the secondary mirror are made by adjusting the three collimating screws in the back of the secondary mirror holder.
Cooling fan: The open tube RC design allows for fast cool-down of the primary and secondary mirrors. Built-in fans on the rear cell of the 10” and larger scopes increases the air-flow around the optics to achieve still quicker “cool down” times of the larger primary mirrors. The 6” and 8” scopes do not have primary mirror cooling fans, as their mirrors are small enough to cool down quickly without any external aid.
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