Equipment Library

The Seattle Astronomical Society maintains a library of small and medium size telescopes that may be checked out 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.

See the complete equipment list in alphabetical order.


You can narrow your search of our equipment library by selecting any one of the below keywords.

Astrophotography Beginner Binoculars Camera Intermediate Maksutov Newtonian Refractor Schmidt Cassegrain Visual

All our equipment is currently on loan to other members.

Available Eventually

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

  • Meade ETX-125 (#1)

    Loan ends in 31 days on May 24, 2024 (Friday).

    5 Inch (127 mm) Maksutov-Cassegrain GoTo Telescope

    This Meade ETX-125EC is an older scope and isn't as easy to use as many of today's scopes. It's mount lacks stability and it's a bit bouncy, making it hard to focus., so it is not recommended for beginner or novice observers. That said, it has excellent optics and will provide good viewing if you are patient..  

    The Meade ETX-125EC is a Maksutov-Cassegrain design that folds a long focal length (1900mm) into a relatively short optical tube. The optics are excellent and the Autostar computer provides GoTo operation. It can be pointed manually using the hand controller if you wish to avoid the Autostar setup procedure. However, it is an old scope and the mechanical quality is below average. Users have reported that the telescope tends to bounce when touched, making it difficult to use at high magnification,


  • Orion StarMax 127 EQ

    Currently there are 3 requests to borrow this.

    5 Inch Maksutov-Cassegrain Telescope with Equatorial Mount.

    The StarMax 127 telescope has a long focal length and is ideal for observation of the moon, planets, and double stars, and the 127 mm aperature is large enough for nice views of brighter deep sky objects. The equatorial mount makes it easier to track the moon and planets at high magnification, but can be confusing for beginners.

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: