Focus Scientific

William Optics Gran Turismo 153mm f/7.8 Apochromat Refractor OTA (Blue)

Note: The 50mm guide scope shown here is NOT included.

The William Optics Gran Turismo 153; a 6" triplet APO at an affordable price. You will be astonished by the stunning resolution for both visual and imaging work. And at a reasonably fast f/7.8. Until today this was only a dream at this price!

Many discerning observers consider a 6" apochromatic refractor to be close to the ideal telescope. And for good reason. The lack of a central obstruction, high contrast, good color correction and fine balance between aperture and focal length make for a highly versatile instrument. Add a well corrected and illuminated field of generous size, the not small objects and structures of the deep sky can be encompassed, while detailed views of such tiny subjects as the planets are enjoyed.

The GT153 features a top-quality triplet, air-spaced objective, based around an FPL-53 element, and designed by a leader in the field. This instrument is extremely sharp and delivers great color correction. STM coatings boost transmission efficiency and improve contrast.

A new extra heavy duty 3.5" Feather Touch focuser rounds out the robust mechanics. Its beefy construction assures no sag nor slippage. Large aluminum knobs afford precise control. 360° rotation permits to frame your subject when imaging.

Have you always dreamed of taking tack-sharp, full-frame pictures of the heavens? Now is the time to join that club! Few other refractors in this size class have a dedicated field flattener. A graduated scale on the focuser tube makes switching between different camera/accessory configurations a snap.

Fit and finish are simply beautiful. No plastic parts or cast bits here! Pieces are CNC machined from solid, high-grade aluminum. The white powder-coated CNC-machined aluminum tube, anodized accents, retractable, engraved dewshield and anodized rotatable focuser make for artful aesthetics that complement superior performance.

Attention to detail is borne out by the precision objective cell, all-CNC machining and Zygo interferometric testing of all systems.

Features and Specifications

  • Aperture: 153mm (6.02")
  • Focal Ratio: F/7.8
  • Focal Length: 1194 mm
  • Objective Type: Synthetic Flourite FPL-53 Triplet, Air Spaced, APO
  • Fully Multi-Coated, STM coating
  • Image Circle Diameter: 44mm with flattener
  • Lens Shade: Retractable
  • Focuser: 3.5" Feather Touch Focuser with 1:10 Dual Speed micro focuser
  • Dial Type Thermometer Built into Focuser
  • Bhatinov Mask Cover for Critical Focus
  • 2" and 1.25" Adapters with Compression Ring
  • Tube and Guidescope Rings
  • Losmandy style dovetail mount
  • Integrated Carry Handle
  • Tube Length: 1100 mm (43.3") Fully Retracted
  • Tube Weight, including Mounting Rings: 13.5kg (29.5 lbs)
  • Two year warranty