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Planewave DeltaRho 500 Optical Tube Assembly

SKU 200128Q
Original price $60,000.00 - Original price $60,000.00
Original price
$60,000.00 - $60,000.00
Current price $60,000.00


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After successfully introducing the DeltaRho 350, the DeltaRho 500 is now available for transcending the challenges of-ultra wide field imaging. With a primary mirror that is fixed in place, collimation is quickly achieved with a simple adjustment to the tip and tilt of the secondary mirror. With more than twice the light-gathering power of the DeltaRho 350, maximizing the performance of your astrograph has never been easier due to PlaneWave’s pursuit of the perfect telescope!

  • Corrected Cassegrain focus optical design
  • Aperture – 508 mm (20″)
  • Focal length – 1537 mm
  • Focal Ratio – f/3.03
  • 70mm Image Circle > 2.6 degrees
  • Fixed Primary Mirror
  • Collimation performed via 3 tip/tilt screws at the secondary mirror
  • 9.166” (232.8 mm) from mounting surface (without focuser and rotator).
  • Backfocus of 5.81″ (147.6mm) with Series-5XL focuser and Series-5 Rotator installed (with focuser at midpoint of travel range).
  • Built-in primary and secondary dew heaters with temperature sensors
  • Compatible with L-500 or 600 series direct drive mounts.
  • Our team at PlaneWave is passionate about designing exceptional telescopes so that users around the world are able to capture the most awe-inspiring astro images possible. From design to manufacture, our goal with the DeltaRho 500 was centered around creating a revolutionary wide-field telescope. The DeltaRho 500 is a Cassegrain Optical Design with the imaging train at the back of the telescope to prevent obstruction of the instrument. This offers a real advantage against prime focus designs, which can severely limit users’ ability to operate with filter wheels or large cameras. Witness the incredible breakthrough in telescope technology as the DeltaRho 500 operates at f/3 and 1537 mm focal length, which is sure to revolutionize your astrophotography.

    Last, but not least, the DeltaRho 500 provides a flat field, which ensures stunning clarity from corner-to-corner images without field curvature degradation. The DeltaRho 500 offers the simplicity of single-mirror collimation, stray light control of advanced 3D printed baffles, and structural performance created through finite element analysis (FEA). DeltaRho 500 users can experience pinpoint stars edge-to-edge and a 2-degree field of view when using large 16803/4040 (52mm) size camera sensors. This field of view is over twice as large as our CDK 20! This kind of equipment allows users to experience a whole new level of wide-field imaging that can bring them closer than ever to deep space. The DeltaRho 500 allows nothing to stand in between the user and amazing astro images.

      Carbon Fiber Tube Design – Minimizes thermal expansion which causes focus shift as temperature changes during an imaging session. Carbon fiber also reaches ambient temperatures quickly and is extremely lightweight and rigid to help ensure that excellent imaging data is produced.
      Collimation software – Along with the included collimation mask, PlaneWave Collimation software allows for quick and easy collimation necessary to maximize the performance of a fast f-ratio optical system. 
      3D Printed Baffles – PlaneWave’s digital 3D printing technology adds successive layers of material to our baffle systems for lightweight, precision-positioned internal stray light control to minimize vignetting and maximize image contrast. 
      Cooling Fans – Three fans are strategically placed on the backplate of the optical tube to ventilate through the telescope and by the primary mirror. Four additional fans on the side of the optical tube provide airflow across the primary, bringing thermal equilibrium efficiently to prevent distorted images due to temperature variations.

      The fans are controlled via the PWI 4 software with the PlaneWave Series 5 Controller sold separately.
      Dew Control Ready – For added dew prevention, the DR500 is internally wired with polyimide film heater pads and a temperature sensor, which is ready to be controlled with the Series 5 Controller via PWI 4 software. 

      Optical System

      Optical Design Corrected Cassegrain
      Aperture 508 mm (20 inch)
      Focal Length 1537 mm (60.5 inch)
      Focal ratio f/3
      Central Obstruction 59 % by diameter
      Back Focus from Mounting Surface (No focuser/rotator installed) 9.166 in (232.8 mm) from mounting surface;  7.271 inch (184.7 mm) from lens cell
      Weight 165 lbs (75 kg)
      OTA Length 35.1 inch (892 mm)
      Optical Performance (Spot Diameter) 3.86 micron RMS on-axis, 4.04 micron RMS at 22 mm off-axis, and 6.04 micron RMS at 35 mm off-axis (Spot Diameters)
      Telescope Cage Carbon fiber truss poles with carbon fiber shroud
      Optimal Field of View 70mm image circle

      Secondary Mirror

      Diameter 286 mm (11.26 inch)
      Material Fused silica (quartz)
      Shape Spherical
      Coating Enhanced aluminum – 96%

      Primary Mirror

      Optical Diameter  20 inch (508 mm)
      Outer Diameter 20.8 inch (528 mm)
      Shape Prolate ellipsoid
      Material Fused silica (quartz)
      Coating Enhanced aluminum – 96%

      Lens Group

      Diameter 160 mm (6.3 inch)  Largest Lens
      Number of lenses Three
      Coating Broadband AR Coatings (on avg. less than .5% reflected from 400 to 700 nm)

      Standard Features

      Corrected Cassegrain The corrected design yields a flat field free from off-axis astigmatism, coma, and field curvature.
      Carbon Fiber Truss Design Minimizes thermal expansion which causes focus shift with changes in temperature.
      Dovetail Expansion Joint Allows for the difference in thermal expansion between carbon fiber and aluminum. The expansion joint allows the aluminum dovetail expand and contract without stressing the carbon fiber lower truss
      Cooling Fans Three cooling fans blow air inside the back of the telescope. This helps the telescope to reach thermal equilibrium quickly. The fans are controlled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.
      Delta-T Ready For added dew prevention, the DR350 is internally wired with polyimide film heater pads and temperature sensor, ready to be controlled with the optional Delta-T controller.
      Included Items
      Heating elements for dew prevention  The heating pads on the primary and secondary mirror require the Series 5  Controller (sold separately).
      OTA Cover  Which protects the primary mirror and the inside of the optical tube.
      Flashdrive  Contains software and instructions for collimation and spacing the primary to the secondary mirror.
      Wrench Set (5812A35)  Standard hex wrenches (European orders only) 


      For the DeltaRho 500 and Series-5XL Focuser:

      To achieve proper mechanical clearance, a 0.5″ spacer (#6003165) is required.

      If the user plans on using our Focuser and Rotator, the 0.5″ spacer is placed in between the Focuser and Rotator, then the Tip-Tilt Adapter.

      If the user plans on using only the focuser, the 0.5″ spacer, assembles as follows: OTA, Focuser, Spacer, then Tip-Tilt Adapter.

      The Tip Tilt Adapter is compatible with the Series- 5XL Focuser, as both focuses and the tip-tilt accessory use the 7.125″ flange interface.

      Recommended Accessories

      L-500 Direct Drive Mount (600550)

      Piggyback Dovetail Bar (201990)

      Series-5XL Focuser (6071001)

      Series-5 Rotator (6021001)

      Series-5 Controller (600199)

      Tip-Tilt Adapter for Series-5 Focuser or Rotator to SecureFit (6061006)