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.


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 Soon

The following list of equipment is currently loaned out, loan ends in the next two weeks, and no one else has requested to borrow it. This is a great time to request to borrow it!

  • Celestron NexStar 6 SE

    Currently there are 4 requests to borrow this.

    Six Inch Computer Controlled (GoTo) Schmidt-Cass Telescope (SCT)

    The Celestron 6 SE is a current model computerized Schmidt-Cassegrain telescope. The 6 SE features a relatively long 1500mm focal length (f/10) and a total weight of 30 lbs including the tripod. 

  • Orion StarMax 127 EQ

    Currently there are 3 requests to borrow this.

    Currently assigned to the SAS Outreach Team

    5 Inch (127 mm) Maksutov-Cassegrain Telescope with Equatorial Mount.

    Request queue is long. Contact the Equipment Manager for an estimated availability date.

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

Available Eventually

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

Available by Request

Contact the Equipment Manager for more information on borrowing the following equipment.

  • Meade ETX-125 (#1)

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

    Special Item: Contact the Equipment Manager to borrow this older telescope

    5 Inch (125 mm) Maksutov-Cassegrain GoTo Telescope

    This is an older computer controlled telescope. Optical quality is very good but mechanical quality is not as good as newer telescopes. The GoTo setup procedure must be followed exactly. Beginners may need assistance.

    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. Setup involves several steps that may be confusing for beginners,

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: