Get your 2024 Banquet tickets!

It is that time to come together for a night of community, recognition, and celebration of a great year ahead of us. Click here!

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.

  • AWB 130mm Reflector

    Currently there are 2 requests to borrow this.

    Table Top f/5 Newtonian Telescope.

    NOTE: This scope does not include a tripod and is designed to be placed on a small table or similar support. It has an open tube and must be shielded from nearby streetlight or porch lights.

    This telescope is suitable for all ages and is a good choice for viewing the moon, planets, and bright deep sky objects. It has a Dobsonian style mounting that is compact and intuitive to use.  It is designed to be placed on a small table or similar support and does not come with a tripod.. A red-dot reflex sight and a set of eyepieces are included..

  • Celestron Echelon 16x70 Binoculars

    Currently there are 3 requests to borrow this.

    High Power Astronomy Binoculars

    Large-aperture astronomical binoculars are intended for wide angle viewing star clusters, nebula, and galaxies, but will also provide nice views of our Moon and Jupiter with it's four Galelian moons. These 70mm binoculars are heavy and an Orion parallelogram binocular mount and tripod is included. 16x magnification is sufficient to provide nice views of many deep sky objects, such as the Andromeda Galaxy (M31),, the Orion Nebula (M42),  and the Great Globular Cluster in Hercules (M13). It will not show Saturn's ring (about 30 power is required to reveal this detail).

  • Meade ETX-125 (#1)

    Currently there are 1 requests to borrow this.

    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 80mm ED Refractor

    Loan ends in 94 days on May 24, 2024 (Friday).

    High Quality 80mm Refractor. Optical tube only at this time; the Mount is out for repairs. 
    Note for experienced users: The optical tube can be used with any mount with a Vixen-style saddle. Contact the Equipment Manager for more information. 

    The Orion 80ED is a small, general purpose refractor telescope that will give sharp images of the moon and planets as well as the brighter star clusters and galaxies. ED glass improves the image contrast compared to a traditional acromat. The Twilight I Alt-Az mount is easy intuitive to use.

  • Orion SkyQuest XT10i

    Currently there are 2 requests to borrow this.

    10 Inch Dobsonian Computer Aided (PushTo) Telescope

    Important: This is a heavy and bulky telescope and it is usually loaned for extended periods.  It may require 2 people to lift it and a bigger vehicle to transport it.

    The Orion SkyQuest XT10i IntelliScope is a 10" aperture Dobsonian Reflector with a Push-To computer system for aiming the telescope. 

  • Orion StarMax 127 EQ

    Currently there are 2 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.

Restricted Equipment

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

  • Celestron NexStar Evolution 6 (#1)

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

    Not currently available for loans

    Six Inch GoTo Schmidt-Cass Telescope (SCT)

    This telescope is a premium model 6 inch NexStar telescope. The loaner kit includes eyepieces, a "Red Dot"  finderscope for initial alignment, and a  good quality 1.25” star diagonal.

  • Celestron NexStar Evolution 6 (#2)

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

    Not Available for loans

    Assigned to the SAS Outreach Team

    Six Inch GoTo Schmidt-Cass Telescope (SCT)

    This is a premium model Celestron 6 inch NexStar telescope. The loaner kit includes a "Red Dot" finderscope for initial alignment, eyepieces, and a  good quality 1.25” star diagonal.

  • Meade 8" LX200 Schmidt Cassegrain

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

    8 Inch GoTo Schmidt-Cass Telescope (SCT)

    Not Available for Loans

    This is a heavy, bulky telescope . The optical tube assembly includes the fork mount and weighs 43 lbs. It is stored in a plastic tub that is 30" x 20" x 16" (L,W,H).  

    Contact the Equipment Manager ( for more information.

    This is a Meade eight Inch aperture, fork mounted,  f/10 GoTo Schmidt-Cassegrain telescope. The GoTo pointing accuracy is very good but the setup and alignment directions contained in the Quick Start guide must be carefully followed. Note that this kit does not include an optional equatorial wedge, since this is not required for visual observing.

  • Orion SkyQuest XT10g - Computerized GoTo Dobsonian

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

    The XT10g is a 10" aperture GoTo Dobsonian Telescope.

    Restricted Item -This is a big telescope. Thee optical tube weighs 30 lbs and is about 12 inches in diameter by 48 inches long. The base weighs nearly 40 lbs. It may require a bigger vehicle to transport it.

    Contact the Equipment Manager ( for more information.


    IMPORTANT: This is a  very heavy and bulky telescope. 

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: