Used Gear Sales Browse brandsOPT PROFESSIONAL SERVICES & SOLUTIONS A World Leader in creating advanced astronomical systems We provide systems for Space Situational Awareness, educational research, government projects, and commercial customers alike. Learn moreAs...
Focal ratio is a measurement used to determine how fast a telescope gathers light. It’s a simple formula that takes the focal length divided by the aperture. For example, if a telescope has a focal length of 480mm and an aperture of 80mm, it would have a focal ratio of f/6. Fast ...
The personal information submitted in connection with this request will be used for the purpose of processing your request. Visit our Tensar Western Hemisphere Corporate Privacy Policy to learn more about our privacy practices.Where to Buy Find Tensar Products Get contact information for your local ...
Used Gear Sales Browse brandsOPT Return Policy Standard 30-Day Return If you would like to return a product, contact us for a return authorization number (RMA). Shipping and handling costs are non-refundable. A full refund for the product will be given if the product is unopened and una...
faint deep sky objects, we want as close to a 5-7mm exit pupil as we can get because it means we're letting our eye take full advantage of the telescope's light-gathering ability. For planetary observing, the objects are so bright that a smaller exit pupil can be used, such as 1-...
Though less common, telescopes like the Classic Cassegrain and the (non-corrected) Dall-Kirkham designs are excellent reflectors used primarily for high-end planetary viewing and imaging. Since these telescopes use an all-mirrored design, they are generally considered superior to other planetary telesc...
Discount codes and/or coupons are one per order and can not be combined or used towards additional gift cards. OPT, LLC reserves the right to approve or deny any discount, gift card, or coupon code. Sales Tax In California California is a mixed-sourcing state. The tax rates are taken fr...
When used in alt-az mode, some hybrid mounts can even carry two telescopes of similar weight at once. This can give an added benefit of observing at multiple focal lengths without swapping eyepieces. Of course, the added functionality of both AZ and EQ modes mean that hybrid mounts cost ...
Motorized & Computerized GoTo Equatorial Mounts help make it easier to get a start in astronomy. Explore the night sky quicker than ever! Find yours here!
Used Gear Sales Browse brandsApochromatic Telescopes Apochromatic Telescopes are a type of refracting telescope that have a better correction of chromatic and spherical aberration than the more common achromat lens. Shop OPT's wide selesction of apochromatic telescopes below! The lenses in an apo...