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.

Available Immediately

The following list of equipment is immediately available to borrow.

AWB OneSky 130mm Reflector

Currently there are 1 requests to borrow this.


The AWB (Astronomers Without Borders) OneSky telescope is a 130 mm Newtonian reflector. It has a Dobsonian style mounting that is compact and intuitive to use. A red-dot reflex sight serves as a finder for aiming the scope. The truss tube telescope collapses into a compact size for storage and transport. Note that this telescope is designed to be placed on a small table or similar support when in use and does not come with a tripod.

Two eyepices are included. The low power eyepiece (25 mm focal length) provides 26 power and a wide, 2 degree true field of view for locating objects and for viewing large deep sky objects (star clusters, nebulae, and galaxies). The high power eyepiece (10mm focal length) provides 65 power for viewing the Moon, planets, and smaller deep sky objects.

This telescope is suitable for all ages and is a good choice for viewing the moon, planets, and bright deep sky objects. The red-dot finder is easy to use. However, you need to be able to see your target in the sky order to aim the scope accurately. In the city, a red-dot finder works well when aiming at the moon, planets, and bright stars. Finding faint deep sky objects generally requires dark sky unless, like the Great Orion Nebula, the object you are looking for is located near a bright star.

It is always good to set up a telescope away from any direct line of sight to porch lights or street lights, and this is especially important for an open truss tube  design like the AWB 130.

Aperture: 130 mm
Focal length: 650 mm (f/5)
Eyepieces: 25 mm (26x) and 10 mm (65x)
Tube length collapsed: 24 inches
Tube length collapsed: 14.5 inches
Telescope weight: 14 pounds

Celestron StarHopper 8

Currently there are 1 requests to borrow this.


This Celestron Star Hopper Dobsonian is an 8 inch Newtonian telescope on a Dobson style mount. Dobsonian telescopes are cost effective and provide good views of celestial objects.

Available Soon

Available Eventually

None of our equipment is loaned out to any members.

Currently Unavailable

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: