PLANEWAVE CDK700 OBSERVATORY SYSTEM
PLANEWAVE CDK700 OBSERVATORY SYSTEM is not in stock but it can be backordered.
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PlaneWave Instruments brings a fully automated observatory class telescope to the market with the CDK700, a 0.7 meter Alt-Az telescope system, combining the revolutionary CDK optical design that founded PlaneWave Instruments with an innovative direct-drive alt/az mount technology that sets a new standard for small observatory telescopes.
CDK700 Features
- Pinpoint stars out to a 70mm image circle
- Ultra-low thermal expansion fused silica optics
- Dual Nasmyth focus, allowing simultaneous mounting of two instruments or easy switching between visual and imaging use
- 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 modelling software
- Now compatible with Series-5 Low Profile Focuser/Rotator
- Optional hard upper shroud and mirror shutter for environmental protection
- Edge Controller electronics enables direct web-based control with built-in Wi-Fi, 5G and LTE
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 professionals do it!
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.
Rotating tertiary mirror
The CDK700 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 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.
All PlaneWave telescopes feature the following ports for dew heater and fan management:
- Two RCA connectors to power the dew heater (from the Delta T or from a 12V source)
- One RJ connector for the Delta T to the telescope to transmit temperature data
- One EFA connector to power the fans (EFA to 5.5-2.1 jack included)
- One auxiliary output port
The built-in dew heaters can be powered by any 12V DC source which has an RCA connector, but the Delta T is required to keep the mirror just above the dew point to avoid overheating and the resulting internal turbulences.
The EFA connector can be powered by the separate EFA controller, any 12V DC source using the supplied EFA to 5.5 x 2.1 jack, or by the Series-5 controller.
Optics
Optical system
| Aperture | 700 mm (27.56") |
|---|---|
| Focal length |
4540 mm |
| Focal ratio |
f/6.5 |
| Central obstruction |
47% of the primary mirror diameter |
| Backfocus from mounting surface |
309 mm |
| Optical performance (400-900 nm) |
1.8μ RMS at 25 mm on-axis; 4.4μ RMS at 21 mm off-axis; 6.8μ RMS at 35 mm off-axis |
| Image scale |
22μ per arcsecond |
| Optimal field of view | 70 mm image circle |
| Construction |
Dual truss structure with Nasmyth focus |
| Fully baffled field | 60 mm |
| Weight | 544 kg |
| Dimensions | 93.73″ H x 43.25″ W x 39″ D |
Mechanical structure
| Fork assembly |
Space frame steel truss |
|---|---|
| Fork base | Welded stainless steel torsion box |
| Instrument payload | 136 kg |
| Optical tube |
Dual truss structure with Nasmyth focus |
Motion control
| Motors |
Direct Drive 3 Phase Axial-Flux Torque Motors |
|---|---|
| Encoders |
255 mm stainless steel encoder ring with read-head yields 67.1 million counts per revolution of the telescope with ~0.019 arc-second resolution |
| Motor torque |
Approximately 170 ft-lbs continuous (Azimuth motor) |
| Drive electronics |
Elmo Motion Control Systems drives |
| Control software | PWI4 & PointXP mount modelling software by Dave Rowe, ASCOM compatible |
System performance
| Pointing accuracy | 10 arcsecond RMS with PointXP Model |
|---|---|
| Pointing precision |
2 arcsecond |
| Tracking accuracy |
<0.2 arcsecond error over 10 minute period |
| System natural frequency |
16 Hz or greater |
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Mount type
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Payload capacity300 lbs (150 ft-lbs) mounted on the field derotator plate
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Drive type
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Encoders
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Dovetail saddle
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Slew speed
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Tracking accuracy
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Pointing precision
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Periodic error
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Optical design
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Aperture
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Focal length
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Focal ratio
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Corrected field70 mm
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Backfocus309 mm from mounting surface
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Focuser type
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Weight

