Equipment Library

The Seattle Astronomical Society maintains a library of small and medium size telescopes that may be checked out for a period of 1 month by members in good standing. If you are new to astronomy, this is an excellent way to learn how to use a telescope and to begin viewing the wonders of the night sky, without having to invest immediately in a telescope of your own. To check out a telescope, please check out our equipment available for loan.

If you have any questions about borrowing equipment, or do not see a specific piece of equipment please reach out to our Equipment Manager.


Equipment currently shown is filtered to only those tagged with Beginner

Available Immediately

All our equipment is currently on loan to other members.

Available Soon

Available Eventually

The following list of equipment is currently loaned out to a member, and may include other members waiting to also borrow.

Orion StarMax 127 EQ

Due back in 34 days on April 20, 2018 (Friday).

127mm (5") aperture combined with a very long 1540mm focal length make the StarMax 127 a Maksutov-Cassegrain telescope with multiple proficiencies. Ideal telescope for sharply detailed views of planets such as Mars, Jupiter, and Saturn, as well as the Moon and brighter deep -sky gems. High-resolution imaging and visual performance in a telescope only 14.5" long!. Includes sturdy adjustable tripod and AstroView equatorial (EQ) mount for convenient slow-motion celestial tracking. Includes a 25mm Sirius Plossl 1.25" telescope eyepiece, 6x30 finder scope, 90-degree mirror diagonal, soft case for the optical tube and accessories, EQ mount polar -alignment scope, Starry Night software, and more!

Currently Unavailable

All our equipment is in good condition!

Telescope Types

Types of telescopes

Copyright NIAAS, North Ireland Amatuer Astronomical Society

What are those numbers?

Types of telescopes

Copyright 2008-2012

The f-ratio is the focal length divided by the diameter of the telescope. Magnification is the focal length of the telescope divided by the focal length of the eyepiece.


To find the f-ratio of a telescope 10 " in diameter with a 45" focal length:

Divide 45 " F.L. by10" D. to get an f-ratio of 4.5.

Compute Magnification

First, convert focal length to mm: 45" = 1146 mm, then:

1146 mm focal length divided by 35 mm eyepiece equals 33 magnification.

More Information

If you are interested in learning more about telescopes, we recommend: