Corrected Newtonian 400

400 mm f2.5 widefield - 6 micron spots

The humble Newtonian telescope, done properly. These instruments are for amateurs who have outgrown their mass produced telescope. Our newtonian telescopes feature 1/8th PTV optics and an integrated corrector.

Each corrected newtonian is available in two speeds, f/4 or f/7. This gives a choice between relatively fast deep sky or a slower system with higher native magnification for smaller DSO’s or lunar/solar/planetary observations.

Price (Excl.VAT)


Aperture (mm)400
Recommended mount typeGEM
Tube tubeClosed
Focal length (mm)1600
Tube length (transport)1150
Tube length (operating)1450
OTA Weight (kg)34
Back focus150
Focal ratio F/4
Fully corrected imaging circle (mm)50
Cooling fansPrimary and secondary mirror
AirflowLaminar flow & Rear
Mirror coatingsEnhanced Aluminium + SiO2 protective layer
FocuserDual speed JTW Rhino
Tube constructionCarbon fiber
Optical surface quality (Strehl, PTV)0.97, 1/10
Primary mirror substrateSchott Supremax 33
Primary mirror cell18 point floatation cell
Primary mirror edge support6 point athermalised
Primary baffleOTA baffles
Secondary mirror substrateSchott Supremax 33
Secondary mirror cell3 point RTV
CorrectorIntegrated 2-element
BoltingA4 Stainless steel
Metal protectionDual
Surface treatmentAluminium – 20 micron hard-coat anodising
PaintExterior grade powdercoat (environmentally friendly)
Anti dew systemOptional