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JTW Astrograph 250 f/4 or f/7
£2,269.00 inc. tax

£1,890.83 ex. tax
? Tax based on United Kingdom.

Description

JTW Astronomy Astrograph 250mm (f/4 or f/7)


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 DSOs or lunar/solar/planetary observations.

Please choose either f/4 or f/7 from the drop down menu at bottom of page



f/4 Specification


Aperture (mm) 250
Recommended mount type GEM
Tube tube Closed
Focal length (mm) 1000
Tube length (transport) 625
Tube length (operating) 825
OTA Weight (kg) 11
Back focus 150
Focal ratio F/ 4
Fully corrected imaging circle (mm) 50
Cooling fans Primary mirror
Airflow Rear
Mirror coatings Enhanced Aluminium + SiO2 protective layer
Focuser Dual speed JTW Rhino
Tube construction Carbon fiber
Optical surface quality (Strehl, PTV) 0.97, 1/10
Primary mirror substrate Schott Supremax 33
Primary mirror cell 9 point floatation cell
Primary baffle OTA baffles
Secondary mirror substrate Schott Supremax 33
Secondary mirror cell 3 point RTV
Corrector Integrated 2-element
Bolting A4 Stainless steel
Metal protection Dual
Surface treatment Aluminium – 20 micron hard-coat anodising
Paint Exterior grade powdercoat (environmentally friendly)
Anti dew system Optional



f/7 Specification


Aperture (mm) 250
Recommended mount type GEM
Tube tube Closed
Focal length (mm) 1750
Tube length (transport) 1375
Tube length (operating) 1575
OTA Weight (kg) 12
Back focus 150
Focal ratio F/ 7
Fully corrected imaging circle (mm) 50
Cooling fans Primary mirror
Airflow Rear
Mirror coatings Enhanced Aluminium + SiO2 protective layer
Focuser Dual speed JTW Rhino
Tube construction Carbon fiber
Optical surface quality (Strehl, PTV) 0.97, 1/10
Primary mirror substrate Schott Supremax 33
Primary mirror cell 9 point floatation cell
Primary baffle OTA baffles
Secondary mirror substrate Schott Supremax 33
Secondary mirror cell 3 point RTV
Corrector Integrated 2-element
Bolting A4 Stainless steel
Metal protection Dual
Surface treatment Aluminium – 20 micron hard-coat anodising
Paint Exterior grade powdercoat (environmentally friendly)
Anti dew system Optional

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Product Code
- JTW-Astro250
Product Condition
- New
Brand
- JTW OTA

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