Introduced in response to growing demand for quality lightweight nitrogen waterproof telescopes and developed around an optical system featuring objective lens sizes of 66.5mm and 81.5mm, GS fieldscopes set the standard for customers wanting to take-out and walk-about with their equipment whether pursuing birdwatching or general wildlife observation.

The models are designed and manufactured to meet the three main requirements demanded by today's active fieldscope user; 'high end' optical performance and value, usability and reliability.

'High end' optical performance and value
The GS series takes the two size model range concept on a stage by increasing the 65mm OG model to a 66.5mm and the 80mm OG model to an 81.5mm without any noticeable gain in size or weight. As a direct result, the GS 815 GA gains 4% surface area over a standard 80mm OG and GS 665 GA 5% over a 65mm OG. The increase in the amount of light entering the instruments results in significantly higher levels of optical clarity over preceding models. Images are extremely bright whilst retaining excellent colour saturation so important for accurate identification.

Which model?
For optimum size & weight to performance ratios, the GS 665 GA warrants serious consideration for users choosing either zoom or fixed magnification eyepiece options. The GS 815 GA models are the preferred choice for those wishing to maximise light transmission at magnifications between 35x and 60x with either one of the three zoom eyepiece options available. The 665/815 ED models afford the size and weight conscious user extra light gathering capability, improved definition at magnifications over 35x plus higher colour fidelity when compared to the standard models. A natural choice for those wanting to experience either the 40862 HDF T zoom or the 40935 SDL zoom eyepieces.

Usability
'Ease of use' and 'functionality' are all important when using an instrument in the field and the GS series are designed to provide class winning optical performance seamlessly in an array of different outdoor conditions.

As telescopes need to be used with a solid tripod for image stability, any weight saving is crucially important. Constructed using lightweight materials where at all possible, the GS 665 weighs under 1060g, and the GS 815 under 1360g. In addition, model GS 815 is perfectly balanced on a tripod when fitted with any HDF eyepiece to eliminate 'drop forward' syndrome common place with many large objective telescopes.

GS Fieldscopes are protected by 'full body' natural rubber armour with a textured finish to the top half of the main body prism housing. The centrally positioned focusing wheel allows easy access for both right and left handed users and is also rubber covered - delivering a positive feel with or without gloves.

The focusing system is designed to allow adjustment from infinity to 50 metres in just a 270° turn. Housed within the same mechanism for convenience is a 9:1 ratio accurate focus adjustment.

Having access to full range of different magnification eyepieces is also important. The GS series are fully compatible with Opticron SDL, HDF & HR eyepieces including; 40862G HDF T 16-48x (665) / 20-60x (815) 40809 HDF T 25xWW (665) / 32xWW (815).

Designed to enable rotation around the main axis of the instrument for use on a bipod or in a hide with a high window, GS fieldscopes feature a solid die-cast tripod sleeve with -/+ 90 degrees each-way action with 45° incremental 'stops'.

To avoid problems of reflected light on the objective lens in bright sunlight all models are fitted with a retractable lens hood extending 28mm (665) and 40mm (815).

Reliability
Extensively tested for continuous trouble free use in varying temperatures, the models are fully nitrogen gas filled and waterproof and come with the assurance of a 30 year guarantee.

SPECIFICATIONS