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.

Keywords

Equipment currently shown is filtered to only those tagged with Celestron

Available Immediately

The following list of equipment is immediately available to borrow.

Celestron StarHopper 8

Currently there are 0 requests to borrow this.

The Star Hopper Dobsonian telescopes are designed for beginners who seek the best possible view of the faint Deep Sky objects while on a constrained budget. These include advanced features that an experienced observer will appreciate.

 

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

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What are those numbers?

Types of telescopes

Copyright 2008-2012 Stormthecastle.com

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: