The AG Optical Systems .5 meter (20 inch) F6.7 Imaging Dall Kirkham (iDK) telescope is an observatory-class imaging instrument featuring an 70mm flat field imaging circle free from coma, astigmatism, and field curvature. The outstanding optical performance of the 20″ iDK is made possible through the convergence of careful design, state-of-the-art manufacturing, and precise assembly. Wide field images are captured with high-contrast details and sharp stars across the entire field of view.
The AG Optical Systems 20″ iDK F6.7 optical system provides exceptional thermal stability. Optical grade fused quartz optics ensure the figure and focus stability of the 20″ iDK as the temperature changes over the course of an imaging session. When combined with the rigid, thermally stable carbon fiber truss tube assembly of the 20″ iDK you can expect to spend less time focusing and more time collecting data.
AG Optical Systems iDK series carbon fiber truss optical tube assemblies make extensive use of carbon fiber composite materials, CNC-machined components, and precision collimation adjustments to provide a rigid and thermally stable platform for the low expansion optics. Two cooling fans speed the cooling of the primary mirror while primary and secondary mirror heaters can be automatically controlled by the optional Thermal Control System (TCS).
The optional, robust, digital Optec Gemini rotating focuser or Optec TCF-S3i focuser is ASCOM-compatible is capable of precision focusing and rotation while carrying heavy CCD imaging trains.
Performance
A permanently aligned integral field corrector eliminates coma, astigmatism, and field curvature across a flat field of view up to 70mm in diameter. When combined with the extensive use of carbon fiber, CNC-machined components, and optical grade fused quartz optics, an iDK Series astrograph is a potent, versatile imaging telescope capable of serious scientific and astroimaging performance.
All AG Optical Systems iDK telescopes use optics crafted by master optician Terry Ostahowski. Ostahowski Optics has been producing professional-grade optics for decades and is recognized for their commitment to quality and customer service.
Innovation
The Imaging Dall Kirkham series of imaging telescopes offer a very versatile F6.7 focal ratio. This focal ratio provides a generous field of view to capture thousands of imaging objects while offering the image scale to frame moderate to small size objects nicely on your CCD sensor.
Dollar for dollar AG Optical Systems is the leader in high-performance imaging systems. Backed by outstanding customer support our astrographs have features that cost extra or are not even available in competing systems, For example, in addition to providing primary mirror and secondary mirror collimation adjustments, every iDK has quartz optics figured by a master optician. AG Optical Systems Imaging Dall Kirkham telescopes offer outstanding optical performance that you can rely on night after night.
Specifications
Optical Tube Assembly
- 140 lbs. carbon fiber tube assembly
- Tube length: 47 inches
- 20″ (.5m) optical grade fused quartz F6.7 optical system
- 70mm corrected imaged circle. 1.2 degrees
- Cooling fans, heaters, and temperature sensors
- Optional Thermal Control System
- Dust covers
- All CNC components, all stainless steel fasteners
Optical System
- 20″ F6.7 corrected optical system with integral field corrector correcting coma, astigmatism, and field curvature
- Ostahowski Optics mirrors
- 3403 mm focal length
- 9.6″ secondary obstruction (48% linear obstruction)
- Performance: 3.2 micron RMS 15mm off-axis, 8 micron RMS 35mm off-axis
- 6.75″ of back focus from Optec Gemini focuser (assumes 1″ extension tube between backplate and Gemini focuser)
- 96% enhanced aluminum coatings
- 89mm diameter two-element permanently-aligned field corrector with broadband anti-reflection coating on all surfaces (<.5% reflectivity from 400 to 700 nm)
- 5.95″ of back focus with Optec TCF-S3 focuser installed
- 10.25″ of back focus from focuser base
In the Box
- Carbon fiber optical truss tube assembly
- Losmandy “D” mount dovetail
- Primary and secondary dust covers
- Primary mirror cooling fans with power cable
- Primary and secondary mirror heaters and temperature sensors
- Low expansion substrate optics with enhanced aluminum coatings
- All stainless steel fasteners and springs
- Backplate carrying handles
Spot Diagram
- .425 through .7 microns wavelength (LRGB)
- 10 micron pixel size
- 70mm image circle (on-axis to 35mm off-axis)
