Gurley pocket solar compass

[surveyor]

This solar compass is able to determine astronomical north based on the passage of the sun. You need to know your latidude upon the face of the earth, and the suns declination for any given day, then if it is nice and level, you turn the base of the instrument and the declination arm, until the image of the sun (shown) appears on the silvered cross hatched target. The inventor of the instrument was William Burt a land surveyor (see wikipedia). Production was taken over by others. This model is actually about half size of the more common solar compasses used for over 100 years.

 

[Reach]

Wow, that’s great! I love old mechanical devices, especially those that have been replaced by electronics.

I have a few old devices, but I’ve never seen one of those. I may have to find one to add to my collection some day.

 

[Shadowscape]

Very cool contraption.

 

[Dan Cobb]

A neat instrument, but it seems pale in comparison to the capabilities of an astrolabe. I've always been impressed that someone invented such a clever analog computer over two thousand years ago. I haven't used mine in years and should brush up on its operation. An astrolabe can be used to tell time (day or night), calculate the position of the sun and bright stars for any date and time, calculate sunrise/sunset times for any date (or rise/set times for bright stars), determine latitude and so on.

 

[surveyor]

The solar compass can also be used to determine the latitude, time of day, Zenith distance and altitude of celestial objects.