Planewave Delta Rho 350
Planewave Delta Rho 350Planewave Delta Rho 350Planewave Delta Rho 350

Planewave Delta Rho 350

£23,229.00✓ 2 year warranty


Out of stock due 40-60 working days

About this product

Model:  baader_delta_rho_350

For many years, the PlaneWave team has dreamed about creating a perfect telescope for widefield imaging. In 2021, PlaneWave Instruments are writing a new chapter in their pursuit of continued innovation and are excited to introduce the game changing Delta Rho 350 telescope.

This f/3 Cassegrain focus telescope has an aperture of 350mm and provides a 1,050mm focal length for capturing stunning deep sky astrophotography. With a beautifully baffled 60mm corrected image circle, the Delta Rho 350 is sure to take your astrophotography to greater heights when imaging with large camera sensors without the limitations of prime focus devices. The 80mm back focus after the focuser allows a variety of cameras, filter wheels, etc. to be attached to the back of the telescope.

Worried about operating fast systems due to image plane tilt? Need not to worry, the Delta Rho’s primary mirror is fixed in place like the CDKs. This makes adjustment very easy. In addition, PlaneWave engineers have designed a new ultra-short de-rotator and focuser that has an adjustable tip/tilt adapter.

In addition to the benefit of a fixed primary mirror, collimation could not be any simpler and all one needs to do is adjust three secondary mirror collimation screws. Cooling fans at the backplate and side of the optical tube helps ensure the system reaches thermal equilibrium quickly for an optimal imaging experience.

DeltaRho 350 Main Details

  • DeltaRho 350 f/3 telescope with Correct Cassegrain Focus and optical CDK design
  • Fast, portable, and stable widefield telescope with a baffled 60mm corrected image circle 
  • With Fused Silica Optics and advanced baffling
  • Carbon fiber optical tube and truss poles
  • With combinable Series-5 rotator and focuser. Together, the combinable rotator and focuser require only 63 mm (2.48"), so these parts leave 80mm back focus for further accessories.
  • Requires a crate #1323514. The crating charge is included in the price of the telescope.


Fast, sharp optics:

The Delta Rho optical design was created by PlaneWave’s CTO David Rowe with the goal of providing a wide, corrected, field of view that yields pinpoint stars across a 60mm image circle. The primary and secondary mirrors are composed of fused silica glass, which ensures that changing temperatures do not distort the shape of the mirrors that can degrade image quality. 

Correct Cassegrain optical design:

The focal plane is set at the back of the Delta Rho 350 so users can install large filter wheels and cameras without blocking the light path, which hinders other fast telescopes in the market.

Advanced baffling:

Our advanced baffling design prevents stray light from entering the light path and adversely affecting your astroimages.

Carbon fiber optical tube and truss poles:

Carbon fibre is extremely lightweight and helps prevent thermal expansion that can distort an imaging system. This adds up to an extremely stable optical tube for an unsurpassed imaging experience.

Cooling Fans

Three Cooling fans have been strategically placed on the backplate and side of the Delta Rho optical tube in order to quickly cool the mirrors to ambient temperatures. Mirrors that are equilibrated to the ambient temperature help the telescope produce the highest quality astro images possible. The fans are controlled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.

Fused Silica

Fused Silica is a synthetic amorphous silica glass of the highest purity and one of the most transparent glasses made. The optical and thermal properties of fused silica are superior to other types of glass due to its purity. Its transmission and homogeneity exceed those of crystalline quartz without the problems of temperature instability inherent in the crystalline form. Fused Silica has a coefficient of thermal expansion six times lower than Borosilicate (Pyrex) glass, which means that as fused silica cools down, it preserves its shape to a high degree of accuracy. This translates into consistent optical performance and unchanging focus over temperature changes. With its high melting temperature ()~ 1.600 degree Celsius), a very low coefficient of thermal expansion and resistance to thermal shock, fused silica is the material of choice for professional observatories as well as various scientific applications.

Optical Design and Spot Size

Back Focus




  • Optical Design: Corrected Cassegrain
  • Aperture: 350mm
  • Focal Length: 1050mm
  • Focal Ratio: F3
  • Image field: 60mm
  • Back Focus Distance: 142.24mm from Mounting Surface
  • Central Obstruction: 56% by diameter
  • Substrate: Fused Silica
  • Optical Length: 584mm
  • Optical Tube Weight: 21kg
  • Tube Material: Carbon Fibre Optical Tube and Truss Poles

Secondary Mirror

  • Diameter: 190mm
  • Material: Fused Silica
  • Shape: Spherical
  • Coating: Enhganced Aluminium - 96% Reflectivity

Primary Mirror

  • Optical Diameter: 350mm
  • Outer Diameter: 468.3mm
  • Material: Fused Silica
  • Shape: Prolate Ellipsoid
  • Coating: Enhanced Aluminium - 96% Reflectivity

Lens Group

  • Diameter: 110mm
  • Number of Lenses: 3
  • Coating: Broadband AR Coatings (less than .5% reflection from 400 to 700 nm)

Please be aware that the new Series-5 controller (#1329200), Series-5 focuser (#1329210) and (if azimuth-mounted) Series-5 rotator (#1329215) will be necessary. Please make sure to order a set of either controller and focuser or controller, focuser and rotator, in order to make use of the DeltaRho .


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