The Tamaya Jupiter is Tamaya's full sized "best value" sextant. The mirrors are large; a 57x42mm index and a 57mm diameter horizon. The inclined handle provides a natural and comfortable grip. Full illumination on both the arc and drum is provided. The optional, interchangeable scope is available in your choice of 4x40 or 7x35. The measuring range is -5 degrees to 125 degrees. The accuracy is +/- 12 seconds. The 4 x 40mm telescope has a 7 degree angle of view and the relative brightness is 100. The 7x35mm telescope has 6.5 degree angle of view and the relative brightness is 25. All optics are fully coated. The frame is lightweight die cast aluminum alloy with corrosion resistant black finish. The vernier scale reads to 0.2'. The index mirror is 57x42mm and it is aluminized on the rear side. The horizon mirror is 57mm diameter. There is 4 shades for the index mirror and 3 for the horizon mirror . It weighs 3 lbs. 12 oz. and it's carrying case is molded plastic with two slide locks.