NAKOH 60GT f/6 TRIPLET REFRACTOR

Name: NAKOH 60GT f/6 TRIPLET REFRACTOR
Brand: Testar Australia
SKU: NA-60GT
Price: 1599.00 AUD
Availability: OutOfStock

$1,599^00AUD

SKU: NA-60GT

The NAKOH 60GT is a premium apochromatic triplet refractor telescope designed to excel in astrophotography and visual observing. With one piece of Japanese-made SD glass and one piece of ED glass, the 60GT delivers consistently sharp, high definition views with minimal chromatic aberration.

The 60GT offers a 60mm aperture and f/6 focal ratio, with a focal length of 360mm, making it ideal for capturing extended nebulae and supernova remnants. When paired with the dedicated 1x field flattener or 0.65x flattener/reducer, the corrected image circle is 44mm, perfect imaging for full-frame sensors.

The NAKOH 60GT fully leverages the anomalous dispersion characteristics of both its SD and ED glass elements to effectively suppress chromatic aberration and enhance image sharpness across the field. The 60GT achieves a central star RMS radius of approximately 2 microns and less than 2.5 microns at the edge of the 44mm image circle (when paired with the 1x flattener or 0.65x reducer).

Spot diagram showing correction of the 60GT with dedicated 1x field flattener.

Spot diagram showing correction of the 60GT with dedicated 1x reducer.

The below diagrams show the relative illumination, which uses the field radius as the horizontal axis and relative brightness percentage as the vertical axis to illustrate the attenuation of light from the center to the edge of the field of view. Even at the extreme edges of the full frame, the 60GT maintains high brightness, a smoothly declining curve, and consistency across multiple wavelengths, effectively minimizing vignetting.

The optical performance of the 60GT has been rigorously tested using a ZYGO interferometer, which reports a Strehl ratio as high as 0.976, with an RMS as low as 0.026λ (surpassing λ/38), and a PV value of 0.168λ. This far exceeds the diffraction-limited standard, ensuring exceptional image quality.

The 60GT is equipped with a dual-speed 2.5-inch rack-and-pinion focuser, offering smooth and precise movement over a 32mm range. It is also compatible with most electronic auto focusers including the ZWO EAF.

The focuser includes a high-precision 360° rotator with engraved scale and knurled locking screw, allowing fine adjustment of the rotation angle. Also included is a 230mm long Vixen-style dovetail bar and metal clamshell tube rings with a tilted design for superior rigidity. The detachable handle is has threaded M4 and M6 screw holes allowing a variety of accessories to be easily mounted.

Specifications

Optical design	Apochromatic triplet with SD & ED glass
Objective diameter	60 mm
Focal length	360 mm
Focal ratio	F/6
Backfocus	100 mm (prime focus), 55 mm (with flattener/reducer)
Image circle	44 mm (with flattener/reducer)
Dew shield diameter	~95 mm
Tube length	270 mm
Tube weight	2.94 kg
Threads	M68 x 1, 2" barrel, 1.25" barrel
Focuser	2.5" rack & pinion
SKU	NA-60GT