Planewave CDK14
The main telescope of the observatory is a PlaneWave CDK14. This is a 14 inch reflector telescope with a Dall-Kirkham design. One of the main benefits of this telescope is the fact that the corrective lenses between secondary mirror and camera are laser-aligned mounted in the primary mirror housing. This means that the only collimation is via the secondary mirror. In the Dall-Kirkham design, the secondary mirror is spherical, so collimation is a lot easier than similar telescopes of a Ritchy-Crétien design. Originally the telescope was meant to run from a mobile setup in the backyard, but in early 2024 the telescope was moved to a remote observatory in Spain in a permanent setup.
Specifications
Aperture: 356mm
Focal length: 2563mm
Focal Ratio: f/7.2
Image circle: 70 mm
Length: 889 mm
Weight: 22 kg
Truss Design
The CDK14 is built in a so-called truss design, typically used for larger telescopes. It is a very strong triangulated system of carbon-fibre rods. It provides a large amount of rigidity, while keeping the weight down compared to regular tube-based systems.
Collimation
To collimate the CDK series of telescopes, only the three set-screws of the secondary mirror need to be used. The collimation screws are easily accessible at the front of the telescope. No adjustments to the primary mirror need to be made.
Primary Mirror
The primary mirror is a 14” elliptical mirror, which is remarkably light for its size. The total weight of the CDK14 is very comparable to the 12.5” version. A precisely designed large 3D-printed baffle ensures that no stray-light will be entering the light path.
Backplate
The imaging train is connected to the backplate of the telescope via a large plate that sits flush against the scope and held in place with a large ring, bolted with six screws. The fans force air to blow past the primary mirror to shorten cool-down times.
Humidity control
The scope comes equipped with heaters and temperature sensors for both mirrors, but no humidity sensor. The electronics is a real mess and sub-par compared to the quality of the telescope. Using a separate box (Delta-T), mirror heaters can be controlled.
The full rig
Back-focus distance at native focal length is large and allows for a lot of flexibility in designing the optimal imaging trail, with room on the backplate to mount control boxes. To reduce stray light coming into the scope, a shroud can be stretched over the truss.