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.

None of our equipment is loaned out to any members.

Available by Request

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

  • Celestron C102 Acromat Refractor

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

    Celestron 102mm f/10 Equatorial Refractor

    The Celestron C102 is a 102mm aperature, achromatic refractor with a sturdy XLT equatorial mount.. The long f/10 focal ratio provides a sharp image and is ideal for viewing planets, the moon, and bright deep sky objects.

  • Celestron NexStar 6 SE

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

    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. 

  • Meade ETX-125 (#1)

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

    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,

  • Orion StarMax 127 EQ

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

    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. The equatorial mount makes it easier to track the moon and planets at high magnification, but can 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: