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.

Available Eventually

The following list of equipment is currently loaned out to a member, and may include other members waiting to also borrow.

  • Orion Resolux 10.5x70 Astronomy Binoculars

    Currently there are 2 requests to borrow this.

    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.

Currently Unavailable

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

  • Celestron Echelon 16x70 Binoculars

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

    There is a long waiting list for these binoculars. New requests are not being accepted.

    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).

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: