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.

None of our equipment is loaned out to any members.

Currently Unavailable

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

Orion SkyQuest XT10i

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

There is a waitlist for this equipment. New requests to borrow it are not being accepted until spring 2021.

Note: This is a heavy and bulky telescope.  It may require 2 people to lift it and a bigger vehicle to transport it.

The Orion SkyQuest XT10i IntelliScope Dobsonian Reflector features a fairly large 10" apperture mirror combined with the ease of use of a Dodsonian mount. The telescope includes altitude and azimuthal encoders and a computer controller for easy two start configuration and push-to navigation. With the Orion SkyQuest XT10i IntelliScope Computer Controller, the user can select an object to view from the controller's 14,000+ object database. A 9x50 finder scope is included to help aim the telescope. Three included telescope eyepieces, a 25mm, 17mm, and 9mm Sirius Plossl, provide you with views between 48x and 120x respectively. 

Telescope Types

Types of telescopes

Copyright NIAAS, North Ireland Amatuer Astronomical Society

What are those numbers?

Types of telescopes

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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.

Example

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: