PlaneWave 0.7 m Ritchey-Chrétien Automated Alt/Az Telescope System
The PlaneWave Instruments PW700-RC is a 0.7 m (27.6") f/6.5 Ritchey-Chrétien (RC) Automated Alt/Az Telescope System. The PW700-RC has fast Ritchey-Chrétien (or RC) optics made by PlaneWave, a dual carbon fiber truss design, with multiple cooling fans located near the front of the primary mirror to quickly cool the primary mirror and keep its temperature stabilized. The PlaneWave Instruments PW700-RC comes standard with a fork mount direct-drive alt/az mount with high level technology to set a new standard for research class observatory telescopes.
PlaneWave's PW700-RC Automated Alt/Az Telescope System has become the telescope of choice for universities, industry, and astrophotographers. PlaneWave offers the 0.7 m aperture PW700-RC with precision Ritchey-Chrétien optics to meet the custom and critical performance needs of the scientific community. This fully automated Alt/Az Telescope System is an observatory class instrument which will provide a dream research telescope system for a college or university observatory seeking an economical yet high performance optical system for teaching astronomy courses while also doing publishable astronomical research.
PlaneWave 0.7 m Ritchey-Chrétien Automated Alt/Az Telescope System Technical Features:
- Ritchey-Chrétien Optical Design
- Dual Nasmyth focus, allowing simultaneous mounting of two instruments or easy switching between visual and imaging applications
- Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope
- High resolution encoders on each axis for precise positioning
- Zero backlash
- Zero periodic error
- PointXP mount modeling software
- Field de-rotator / rotational field framing
In certain applications such as photometry and spectroscopy, refractive lenses could easily influence scientific data results by altering the spectral content of the acquired data. This could make it difficult to quantify the data. The PW700-RC as offered here in its native format (no field flattening lenses) uses only a primary, secondary, and tertiary mirror with reflective coatings. This can be useful when making scientific observations primarily on-axis as is the case in photometry and spectroscopy, and when wide field imaging is not a concern. Ritchey-Chrétien optics made by PlaneWave will provide excellent on-axis performance using only a hyperbolic primary and secondary mirror with no refractive optics in the light path. The tertiary mirror is a flat and thus has no power.
An alt/az mount is inherently more stable than an equatorial mount since there is no cantilevered mass, nor are there any large protruding counterweights to create a dangerous hazard in a public observatory. An alt/az telescope is also considerably more compact than its equatorial counterpart, allowing a larger telescope to fit in a smaller enclosure. The mass it takes to make a rigid alt/az mount is substantially less, leading to cost savings. Unlike German Equatorial mounts, there are no meridian flips to deal with. You can image from horizon to horizon continuously if desired. Alt/Az is more intuitive to use and no polar alignment is needed. Besides, it is the way the big boys do it!
The carbon fiber truss design of the PW700-RC Ritchey-Chrétien (RC) Automated Alt/Az Telescope System telescope by PlaneWave will minimize problems of thermal expansion to prevent focus shift with changes in ambient temperature. Special dovetail expansion joints accommodate the difference in thermal expansion between carbon fiber and aluminum materials. The expansion joint allows the aluminum dovetail to expand and contract without stressing the carbon fiber lower truss.
Benefits of Nasmyth Focus: The Nasmyth Focus is along the altitude axis so there are virtually no balancing issue as you change out equipment. Eyepieces remain at a constant wheelchair-accessible height, greatly simplifying access to the telescope for public observatories. The rotating tertiary mirror allows you to switch from one Nasmyth port to the other in just seconds, allowing observers to easily transition between imaging and visual use. Also, the provision of Nasmyth foci means it is easier to install large or bulky instruments for gathering data than it would be at a Cassegrain focus.
Rotating Tertiary Mirror: The PW700-RC includes an integrated rotator for the tertiary mirror, with magnetic locks to position the mirror precisely for either Nasmyth focus position. The rotator can move the optical beam from one port to the other in under 10 seconds.
Direct drive motors and encoders: Direct Drive motors mean that there are no gears to cause backlash and periodic error. With high-resolution encoders providing the feedback for the direct drive motors, not only will the telescope track without periodic error or have any backlash at all, but the mount will be able to counter against wind gusts. The direct drive motors can move the telescope at incredible speeds for tracking satellites or just to minimize target acquisition time.
The PlaneWave PW700-RC Ritchey-Chrétien Automated Alt/Az Telescope System has terrific specs for pointing and tracking performance, which is important for doing serious research with this scope. Pointing accuracy is 10 arcsecond RMS when using the PointXP Model, while the Tracking accuracy is 1 arcsecond error or better over a 3 minute track period.
For doing research in astronomy where reliable data is critical, incorporating a mount model program is highly desirable. PointXP5 provides the capability from within software to model your mount performance and its axis offsets, in this case for the Alt/Az mount. A good model will dramatically improve your mount’s performance. On a good mount with a good optical system such as the PlaneWave PW700-RC, PointXP5 can provide pointing performance with only a 5 arcsecond RMS error.
This Ritchey-Chrétien Automated Alt/Az Telescope System model PW700-RC by Planewave is the perfect choice of telescope for a college or university observatory seeking an economical yet high performance optical system for teaching astronomy courses while also doing publishable astronomical research work. It is also an ideal scope for the avid amateur astronomer who will be doing research such as photometry or spectroscopy, or astrometry over a narrow field of view. It will be great for visual astronomy too because of its high quality imagery for nearly on-axis objects.
PlaneWave 0.7 m Ritchey-Chrétien Automated Alt/Az Telescope System Specifications:
- Optical Design: Ritchey-Chrétien Reflector
- Aperture: 0.7 m (27.56")
- Focal Length: 4540 mm (178.74")
- Focal ratio: F/6.5
- Central Obstruction: 47% of the Primary Mirror Diameter
- Back Focus: 305 mm (12") from Mounting Surface
- Weight: 1200 lb
- Focal Positions: Dual Nasmyth foci
- OTA Length: 93.73"
- OTA Width: 43.25"
- OTA Height: 39"
- Fork Assembly: Single piece U shaped fork arm assembly for maximum stiffness
- Azimuth Bearing: 20" diameter thrust bearing
- Altitude Bearings: 2 x 8.5" OD ball bearings
- Optical Tube: Dual truss structure with Nasmyth foci
- Motor Control: Industrial grade Parker brushless motor control system and built in electronics
- Azimuth Motor: Direct Drive 3 Phase Axial-Flux Torque Motor
- Altitude Motor: Direct Drive 3 Phase Axial-Flux Torque Motor
- Encoder - Azimuth and Altitude: 10 inch disk built into the azimuth and altitude axes with stainless steel encoder tape on the circumference with reader yields 16 million counts per revolution of the telescope. This translates to about 0.08 arcsecond resolution
- Motor Torque: Approximately 35 ft-lb
- Drive Electronics: Capable of controlling up to 4 high speed encoders, limit switch inputs, homing switch inputs, controls two additional motors for accessories, two brake outputs and 16 digital and 2 analog inputs
- Telescope Control Software: Incorporates PointXP mount modeling software by Dave Rowe; All software is ASCOM compatible
- Pointing Accuracy: 10 arcsecond RMS with PointXP Model
- Pointing Precision: 2 arcsecond
- Tracking Accuracy: 1 arcsecond error or better over 3 minute period
- System Natural Frequency: 10 Hz or greater
- Field De-Rotator Accuracy: 3 microns peak to peak error at 35 mm off-axis over 1 hour of tracking (18 arcsec)
Primary Mirror Blank
- Radius of Curvature: 4115 mm
- Optical Diameter: 700 mm (27.56 inch)
- Outer Diameter: 714.38 mm (28.125 inch)
- Core Diameter: 203 mm (8 inch)
- Material: Pyrex or Borosilicate Precision Annealed
- Edge Thickness: 2.25 inch
- Cell: 18 points
Secondary Mirror Blank
- Radius of curvature: 2961 mm
- Thickness: 25 mm
- Optical Diameter: 312.4 mm (12.3 inch)
- Outer Diameter: 317.5 mm (12.5 inch)
- Cell: 3 point RTV
Tertiary Mirror Blank
- Optical Major Diameter: 152.4 mm
- Thickness: 25 mm
This telescope weighs 1200 lb. not counting the shipping crate, and will ship truck freight. A member of the OPT staff will contact you will shipping weights and delivery times. An approximate wait time is 4-5 months.
- Additional Information
SKU PI-RC700 Manufacturer PlaneWave Telescope Series Planewave RC Optical Design Ritchey-Chretien Mount Type Alt-Azimuth - Motorized Telescope Aperture 27.5" Telescope Focal Length 4540mm Telescope Focal Ratio f/6.5 Optical Coatings Aluminum Tube Color or Finish Carbon Fiber Length of Optical Tube 56" Optical Tube Weight 240 lb. OTA Mount Type Dual Fork Arms Finder Included None
- Included Items
- PlaneWave 0.7 m f/6.5 Ritchey-Chrétien Automated Alt/Az Telescope System
- Electronics Required for Alt/Az Mount operation
- Software Required for Alt/Az Mount operation (Control Software)
- PointXP mount modeling software
- Field de-rotator
- Primary Mirror Cover
- PlaneWave thumb drive with instructions for collimation and spacing adjustments
- 12 VDC Power Supply for operating fans
- Questions & Answers
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