Page 4
Introduction Congratulations on the purchase of your Opticstar AR80S achromatic refractor. This AR80S telescope is well suited for both astronomical and terrestrial observation. Its high quality achromatic optics, solid construction and very low focal ratio of f5 make it also ideal for deep sky imaging, for use as a guider, or as a travel and spotting scope.
Page 6
If you do not use a diagonal you will need an extension tube to reach focus. Using the AR80S If you are new to observing it is advisable to first use the telescope during daytime to learn how it operates.
Page 8
The fast focal ratio of the AR80S scope makes ideal for deep sky viewing and imaging or for use as guide scope. When conditions are not favourable the maximum useful magnification for most scopes will be around 25-35 times per inch of aperture.
(O3, H-alpha, S2) are recommended depending on requirements. The AR80S is suited for wide field deep-sky imaging due to its low focal ratio, solid structure and Precision Focuser. It is well suited for deep sky imaging when coupled with the Opticstar DS336 XL TEC-cooled camera which supports long exposures in conjunction with very low noise levels.
The focal ratio represents the speed of the telescope’s optics, the focal ratio can be calculated by dividing the focal length by the telescope’s aperture. Telescopes with faster/shorter focal ratios like the AR80S benefit from wider fields of view, and a subsequent increase in brightness and image resolution. Fast f/4-f5 focal ratios are generally best for lower power wide field observing and deep space imaging.
Page 12
Dual-speed Focuser Adjustme nt If your AR80S came with a 1:10 dual-speed focuser this would had been adjusted at the factory. In certain cases it may be necessary to regulate the tension to improve performance by adjusting the silver thumb-screw below the focuser, not too much and not to little.
Need help?
Do you have a question about the AR80S and is the answer not in the manual?
Questions and answers