PlaneWave CDK500 Telescope System f/6.8 - PlaneWave CDK20 Astrograph and PlaneWave L-500 Mount

Based on the technology of our PW-1000 (1-meter) Observatory telescope, PlaneWave combines its revolutionary optical systems with its brand new innovative L-Series direct drive mount that sets a new standard for small observatory telescopes.

PlaneWave CDK500 Telescope System f/6.8 consits of the CDK20 and the L-500 Direct Drive Mount with integrated high resolution encoders and high speed slewing.

The 20" CDK is a telescope optical system that is designed to excel at imaging on large format CCD cameras while remaining an excellent instrument for visual use.

One of the unique features of the CDK design is its ease of collimation and achievable centering tolerance for a telescope of its class. This assures the user will get the best possible performance out of the telescope. The end result is a telescope which is free from off-axis coma, off-axis astigmatism, and curvature of field, yielding a perfectly flat field all the way out to the edge of a 52mm image circle.

PlaneWave CDK500 Telescope System f/6.8 with Fused Silica Optics incl. a CDK20 Astrograph and L-500 Mount

• CDK20 Astrograph, 20 inch, modified to Dall-Kirkham, with fully corrected image field
• with 8" Dovetail, 3.454 mm (f/6,8), 52 mm field of view
• Delta T Ready, 3,5" Hedrick Focuser and EFA Kit separately available
• Requires a crating #1323520. The crating will be charged extra
• L-500, can hold payload of over 200 lbs for CDK20
• Zero Backlash, Zero Periodic Error
• Incredible slew speedup to 50 degrees per second
• With integrated high resolution encoders
• Through the mount cabling
• Requires a crating #1323505. The crating will be charged extra

Fused Silica

Fused Silica is a synthetic amorphous silica glass of the highest purity and one of the most transparent glasses made. The optical and thermal properties of fused silica are superior to other types of glass due to its purity. Its transmission and homogeneity exceed those of crystalline quartz without the problems of temperature instability inherent in the crystalline form. Fused Silica has a coefficient of thermal expansion six times lower than Borosilicate (Pyrex) glass, which means that as fused silica cools down, it preserves its shape to a high degree of accuracy. This translates into consistent optical performance and unchanging focus over temperature changes. With its high melting temperature ()~ 1.600 degree Celsius), a very low coefficient of thermal expansion and resistance to thermal shock, fused silica is the material of choice for professional observatories as well as various scientific applications.

L-Series

The L-Series combines versatility, simplicity and affordability by combining all the technology of our Observatory class telescopes into a compact stand-alone mount.

The mount is equipped with direct drives motors as well as high-resolution encorders. The software is ASCOM compatible and the direct drive motors can move the telescope at incredible speeds for tracking satellites.

In its Alt/Az configuration it is 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, and no large protruding counterweights to create a dangerous hazard in a public observatory. Alt/Az is more intuitive to use and no polar alignment is needed.

L-Series Features:

• Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope
• Slew speeds up to 50 degrees per second
• High resolution encoders on each axis for precise positioning
• Zero backlash, Zero periodic error
• Latitude Range: 0 to 90 degrees, Northern and Southern hemispheres
• Enclosed electronics
• Through the mount cabling: Access panels in the fork arm and azimuth axis allow for camera equipment cabling through the inside of the mount.
• Dual mounting bracket: PlaneWave style mounting bracket to hold CDK17/20 onto inside of fork arm with additional option of mounting a scope on the outside of the fork arm. Optional dovetail clamp required.
• Azimuth dovetail balance system: For precise center of gravity balance whether in Alt-Az or Equatorial configuration

Control System

• User Interface: PlaneWave Interface 4 (PWI4) Control Software with integrated PointXP mount modeling software
• Slew Rate: 20 degrees per second (standard); 50 degrees per second (maximum), both axes
• Home position sensors are included allowing the mount can find its home position on power up.

Scope of Delivery

CDK 20

• Heating elements for dew prevention – The heating pads on the primary and secondary mirror require the #1329110 Delta-T controller and sold separately
• OTA cover - To protect the primary mirror and inside of the optical tube
• Flash Drive - Contains software and instructions for collimation and spacing the primary to the secondary mirror
• Wrench Set(5812A35) - Standard hex wrenches (European orders only)
• Soft cover for secondary mirror
• 12v AC adapter

L-500

• Hardware
  • Six 3/8-16 x ¼" socket head cap screws to bolt the mount to the pier, or wedge.
  • Six 3/8-16 x ¼" washers
  • One extended length shoulder bolt for RA axis to EQ wedge alignment
• Planewave Saddle - wide saddle comes standard with L-500 or L-600 mounts for securing CDK17, CDK20, or CDK24 OTAs. Can do EZ-Saddle at customer request.
• One 16' USB cable - to connect the mount to the observatory control computer
• One 120VAC power cable - To provide to the mount
• Standard Allen Key set - For tightening bolts used on the mount
• Flash drive - Contains PWI4 software for mount control and instructions for installation

Shipping: dimensions and weight

CDK20

• Width: 33 inch (838 mm)
• Height: 33 inch (838 mm)
• Length: 62 inch (1,651 mm)
• Weight: 288 lbs (132.0 kg)

L-500

• Width: 99.06 cm
• Height: 152,4 cm
• Length: 106,68 cm
• Weight: 204,1 kg

The information is only a rough estimate! The actual shipping dimensions and weight may differ.

Specifications

Optics

• Optical Design: Corrected Dall-Kirkham (CDK)
• Aperture (mm): 20" (508 mm)
• Focal Length: 2.939 mm (115.71 inch)
• Focal Ratio: f/6.8
• Image Field: 52 mm
• Back Focus Distance: 10.24" (260 mm) from Mounting Surface, 7.24" (184 mm) from Racked in Focuser
• Central Obstruction: 23.7 % by surface area, 49% of the Primary Mirror Diameter
• Substrate: Fused Silica
• Optical Tube Weight: 106 lbs (48 kg)
• Mount: Alt-Az or Equatorial configuration
• Payload Capacity (kg): 200 lbs (91 kg)

Mount

• Mount Weight: 100 kg
• Latitude Range: 0 to 90 degrees, Northern and Southern hemisphere
• Slew Speeds: 20 degrees per second (standard); 50 degrees per second (maximum), both axes
• Tracking accuracy: < .3 arcsecond error over 5 minute period
• Pointing Precision: 2 arcsecond
• All-sky pointing accuracy: <10 arcsecond RMS with PointXP Model
• System Natural Frequency: 10 Hz or greater
• Control system electronics: PlaneWave Interface dual axis telescope control
• Software: PlaneWave Interface (PWI4). Incorporates PointXP mount modeling software by Dave Rowe All ASCOM compatible
• Homing Sensors: Home position sensors are included allowing the mount can find its home position on power up

Electronics

• Motor Torque: Approximately 20 ft-lbs continuous; 50 ft-lbs peak
• Motor: Azimuth and Altitude: Direct Drive 3 Phase Axial-Flux Torque Motors
• Motor Control: Industrial grade brushless motor control system and built in electronics
• Encoder: 152mm disk built into the azimuth and altitude axes with stainless steel encoder on the circumference with reader yields