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AG Optical - 17" Dall Kirkham Astrograph Telescope

Model#: iDK17

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Availability: In stock


Manufactured by: AG Optical Systems


The AG Optical 17" iDK Astrograph is an excellent astrograph for a wide variety of astrophotography. The telescope has a medium focal ratio of f/6.7 with 6 micron RMS spot size. This means that stars appear very pinpoint while still at large field of view. This is possible because the astrograph is designed with a two element corrector that reduces distortion such as coma and field curvature. In addition, the correctors in the astrograph are permanently aligned and are coated with material of less than 0.5% reflectivity. This RMS spot size can accommodate chips large as 16803 sensors.

AG Optical knows how detrimental stray light is to astrophotography, so they've built in baffles near the primary and secondary mirrors to deflect unnecessary and unwanted light.

When using different focusers for astrophotography, it can be tough to achieve the desired focus and sometimes it isn't possible. Off-axis guiders, filter wheels and many other accessories can increase usage of backfocus. The 17" iDK astrograph has 11" of backfocus from back plate to focal plane which is outstanding! If you want even more options, there are many spacers and adapters available. The Optec TCF-S3i focuser comes with this astrograph. This focuser has a heavy payload for cameras and has great focusing memory and repetition. There is 6" backfocus availability with this Optec focuser.

  • Optics figured and quality tested as a system
  • Fast F6.7 system designed and baffled to cover 16803 size chip
  • 6" to 8.5" of back focus to support almost any combination of imaging components (dependent upon focuser selected)
  • Excellent coma free, astigmatism free, flat field performance over 70 mm image circle
  • Highly robust, precise Optec TCF-S3i focuser is standard.  Optional FLI Atlas focuser.
  • Outstanding field illumination across big chip cameras.
  • Carbon fiber truss tube engineered to provide rigidity and thermal stability.  Optional AGO Thermal Control System to automatically control fans, primary heater, and secondary heater.
  • Multiple spacer and camera adapter options




17" Optical Tube


  • AG Optical has equipped this astrograph with a carbon fiber tube, which is praised for its lightweight and thermal stability.



  • Cleaning and maintaining a telescope is standard. Dust, particles and moisture can infiltrate inside so it is important to clean your optics and instrument once and a while. With precise computer precision, AG Optical has designed their astrograph to be completely disassembled and reassembled without worrying about spacing differences between the internal optics. The aluminum components are also computer machined precisioned.



  • There are three 12 voltage speed variant fans behind the mirror that regulates temperature stability.




Additional Information

Name AG Optical - 17" Dall Kirkham Astrograph Telescope
Manufacturer AG Optical Systems
Model iDK17
Aperture 17"
Backfocus Distance 11"
Cooling 3x80mm cooling fans
Focal Length 114"
Focal Ratio f/6.7
Focuser Optec TCF-S3i
Optical Coatings Enhanced Aluminum mirror coatings
Optical Tube Carbon Fiber Truss
Primary Mirror Supremax 33 low-expansion glass
Secondary Mirror Obstruction 8.2"