Description

Enjoy exceptional optical and tracking performance for astrophotography, or research, with the CDK500 package! Includes a CDK20 optical tube and L-500 mount.

The PlaneWave Instruments CDK20 is a 20 inch (0.51 m) f/6.8 Corrected Dall-Kirkham Astrograph telescope. The CDK20 has a dual carbon-fiber truss design, with 3 cooling fans ejecting air from the back of the telescope. The CDK20 covers a 52 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 140 lbs (64 kg) and comes standard with a back plate retaining ring ready to accept the focuser of your choice.

CDK20 optical tube:

f/6.8 and 3454mm focal length
No coma, no off-axis astigmatism, and no field curvature
Pinpoint stars across a 70mm image circle.
Rock solid fused silica mirrors with low thermal expansion.
Carbon fiber optical tube assembly for rigidity and fast cooling.Simple secondary mirror collimation thanks to the fixed primary mirror.

L-500 direct drive mount:

Zero periodic error, zero backlash, and minimal maintenance due to the lack of gears.

Slew speeds up to 50 degrees/sec for satellite tracking and fast target acquisition.
Sidereal tracking accuracy of < 0.30 arcseconds RMS over 5 minutes.
High resolution optical encoders on both axes for precision feedback.
Can be installed in either equatorial, or alt/az configuration.
Includes PWI4 software (ASCOM compliant) for mount control.

All CDK20 telescopes come with fused silica primary and secondary mirrors.

The L-Series combines versatility, simplicity and affordability by combining all the technology of our Observatory class telescopes into a compact stand-alone mount. 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. Besides, it is the way the pros do it!

L-Series Mount 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
PointXP mount modeling software
Enclosed electronics

Through the mount cabling

Direct drive motors and encoders	Direct Drive motors and on-axis encoders eliminate the need for gears, thereby eliminating 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 and backlash, the mount will also counter wind gusts with precise servo feedback.
Incredible Slew Speed	The direct drive motors can move the telescope at speeds up to 50 degrees per second for tracking satellites or just to minimize target acquisition time.
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
Through the mount cabling	Access panels in the fork arm and azimuth axis allow for camera equipment cabling through the inside of the mount.
Proven CDK700/PW1000 Technology	The L-Series uses the same proven technology as the CDK700 and 1-Meter PW1000 which are being used in Universities round the world.

CDK-500 + Core Accessories

Item Number	Description	Price
200130Q	CDK-500 (CDK20 / L-500)	$47,000
600180	IRF90 Rotating Focuser	$ 4,500
200901	EFA, Focuser Accessory Control	$ 800
Total	$52,300

Specifications

Mount System

Type	Alt-Azimuth / Equatorial Direct Drive Mount
Weight	257 lbs (100 kg)
Component Weights	Azimuth Base – 121 lbs, Fork Arm – 136 lbs
Max. Load Capacity	200 lbs (91 kg)
Latitude Range	0 to 90 degrees, Northern and Southern hemispheres
Cable Management	Equipment cables can be wired through mount

Control System

Control Electronics	PlaneWave Interface dual axis telescope control
User Interface	PlaneWave Interface 4 (PWI4) Control Software with integrated PointXP mount modeling software
Homing Sensors	Home position sensors are included allowing the mount can find its home position on power up.
Slew Rate	20 degrees per second (standard); 50 degrees per second (maximum), both axes
Power Requirement	Accepts 120 VAC. Supplied with 12VDC 15A Regulated Power Adapter

Optical System

Aperture	20 inch (508 mm)
Focal Length	3454 mm (135.98 inch)
Focal ratio	F/6.8
Central Obstruction	39% of the Primary Mirror Diameter
Back Focus from Racked in Focuser	5.8 inch (147 mm)
Weight	140 lbs (63.5 kg)

Motion Control

Motor Control	Industrial grade brushless motor control system and built in electronics
Motor – Azimuth and Altitude	Direct Drive 3 Phase Axial-Flux Torque Motors
Encoder – Azimuth and Altitude	152mm stainless steel encoder ring with reader built into the azimuth and altitude axes. 18,880,000 counts per revolution (0.069 arcsecond resolution).
Motor Torque	Approximately 20 ft-lbs continuous; 50 ft-lbs peak
Drive Electronics	Industrial grade, off-the-shelf brushless motor drives for each axis with custom designed interface card
Telescope Control Software	PlaneWave Interface (PWI4). Incorporates PointXP mount modeling software by Dave Rowe. Provides HTTP and ASCOM control interfaces.

System Performance

Pointing Accuracy	<10 arcsecond RMS with PointXP Model
Pointing Precision	2 arcseconds at sidereal velocity
Tracking Accuracy	< 0.3 arcseconds over a 5 minute period at sidereal velocity
System Natural Frequency	10 Hz or greater

Downloads

L-500 Pier Interface Drawing

L-500 Mount Dimensions

L500/600 Mount Instructions

PlaneWave Interface 4 Software User Manual_V15 1.7.2021

Included Items

Heating elements for dew prevention	The heating pads on the primary and secondary mirror require the 600195 Delta-T controller sold separately
OTA Cover	To protect the primary mirror and inside of the optical tube
Flashdrive	Contains software and instructions for collimation and spacing the primary to secondary mirror

Hardware	Six 1/2-13 x 1 1/4″ socket head cap screws to bolt the mount to the pier, or wedge Six 1/2-13 washers One extended length shoulder bolt for RA axis to EQ wedge alignment
One 16′ USB cable	To connect the mount to the observatory control computer
One 120VAC power cable	To provide power to the mount
Standard Allen Key set	For tightening bolts used on the mount
Flashdrive	Contains PWI4 software for mount control and instructions for installation
Gamepad	Used for control of the mount tracking speeds for visual observing

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