12.5″ Imaging Dall Kirkham Quartz

FA telescopes FA telescopes

Telescope Name: 12.5″ Imaging Dall Kirkham

Telescope Price: $10,690 with quartz optics/heaters/temp sensors

Item #: 125iDKTCSHO

The AG Optical Systems  .3 meter (12.5 inch) F6.7 Imaging Dall Kirkham (iDK) telescope is a semi-portable imaging instrument featuring a huge 60mm imaging circle free of coma, astigmatism, and field curvature.  The outstanding optical performance of the 12.5″ 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 12.5″ iDK F6.7 optical system provides exceptional thermal stability. Optical grade fused quartz optics ensure the figure and focus stability of the 12.5″ 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 12.5″ 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 anti-dew 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 and is capable of precision focusing and rotation while carrying heavy CCD imaging trains.

Optical Tube Assembly

  • 46 lbs. carbon fiber tube assembly
  • Tube length: 31.1 inches
  • 12.5″ (.3m) optical grade fused quartz F6.7 optical system
  • 60mm corrected imaged circle, 1.6 degrees
  • Cooling fans, heaters, temperature sensors
  • Optional Thermal Control System
  • Dust covers
  • All CNC machined components, all stainless steel fasteners

Optical System

  • 12.5″ F6.7 corrected optical system with integral field corrector correcting coma, astigmatism, and field curvature
  • Ostahowski Optics mirrors
  • 2128 mm focal length
  • 6.7″ secondary obstruction (54% linear obstruction)
  • Performance: 5 micron RMS 15mm off-axis, 6.5 micron RMS 30mm off-axis
  • 7.1″ of back focus from Optec Gemini focuser (assumes 1″ extension tube between backplate and focuser)
  • 96% enhanced aluminum coatings
  • 89mm two-element permanently-aligned field corrector with broadband anti-reflection coating on all surfaces (<.5% reflectivity from 400 to 700 nm)
  • 6.3″ of back focus with Optec TCF-S3 focuser installed
  • 10.6″ of back focus from focuser base


Truss shroud

Truss Shroud

Heavy Lycra shroud to block stray light, mitigate dust intrusion

Price: $135

Item #: FA12SHROUD

optec gemini 3.75

Optec Gemini 3.75″ Rotating Focuser

Low profile (2.5″), rotating digital focuser with 20 lbs payload capacity, temperature compensation feature

Price: $3495

Item #: GEMINI

thermal control system

Thermal Control System

Computer-based automated control of primary mirror cooling, primary and secondary mirror anti-dew control

Price: $600



Piggyback Dovetail Plate

CNC-machine 6061 aluminum Losmandy “D” profile piggyback dovetail plate

Price: $235

Item #: FA12PIGGY

Optec TCF 3″ Digital Focuser

Robust, digital 3″ focuser with temperature compensation, Focus Lynx control

Price: $1795

Item: TCFS31


  • 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

12.5″ Imaging Dall Kirkham Spot Diagram

  • .425 to .7 micron wavelength (LRGB)
  • 10 micron pixel size
  • 60mm image circle (on-axis to 30mm off-axis)