The Ranger Seismometer is a seismometer.  If memory serves, the natural
frequency is about 1 Hz, but it might have been adjustable over a small
range.  It can be used as either a vertical or horizontal seismometer. 
The big knob is used to adjust the support spring to center the mass in
either position, and the feet are designed to support it in either
position.  The little window is used to see when the mass is centered.
The mass can be clamped for easy transit.  As I recall, it has a
calibration coil.

It was named after the original "Ranger" moon study program, which
carried three of these in an orthogonal configuration (less the aluminum
case) to the surface of the moon for seismic studies. Once landed on the
moon, little motors centered the units.

Assuming it still works, this unit would be an excellent, short-period
seismometer for your seismic station.

Doug

BOB BARNS wrote:
> 
> Hi,
>   Ebay # 430096282 (ends 9/12) is a "Kinemetrics Ranger Seismometer".
> It looks interesting but I don't know what it is.
> Perhaps someone in the group can post some info about it.
> Bob Barns
>
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