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.

See the complete equipment list in alphabetical order.

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.

  • Orion StarMax 127 EQ

    Currently there are 2 requests to borrow this.

    The StarMax 127 telescope has a long focal length and is ideal for observation of the moon. The equatorial mount makes it easier to track the moon and planets at high magnification, but can be confusing for beginners.

Currently Unavailable

The following list of equipment is not available to members until we are able to replace or repair parts.

  • Meade ETX-125 #2

    Note  This item is being serviced and it is not available for check out.

    Special Item-Contact the Equipment Manager to Borrow this telescope

    This telescope was recently acquired by SAS and is not yet ready to be loaned out. It is the second of two simialr ETX-125 telescopes in the Lending Library.


  • Meade ETX-125 (#1)

    Note  This item is being serviced and it is not available for check out.

    Special Item: Please contact the Equipment Manager to borrow this telescope.

    The Meade ETX-125EC telescope is a Maksutov-Cassegrain design that folds a relatively long focal length into a relatively short optical tube. The long focal length makes it easy to reach high magnification for observation of the moon and planets. The Meade AutoStar controller provides Go-To operation (but AutoStar is an older generation and setup involves several steps),


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: