STANDARD - Survey Instrument Antique Center!

The Surveyors' Solar Attachment.
Placed on the side of the transit it permits the main telescope to be reversed through
the standards at all times.
Our Surveyor's Solar Attachment, or meridian finder, is in principle like Pearson's
(made by us heretofore), not requiring computation, but instead of the lens-bar
it has a small telescope with -inch aperture and 6 inches focal length. This telescope
is provided with a detachable prism and colored glass for the eye-piece, and also a plain
colored glass for use with the main, or solar telescope, and our customary solar square
as in figure RK, page 122.
This solar attaches by means of a screw to the end of the cross-axis of the transit
telescope on the side of the clamp and tangent-screw, as shown in the cut, and when
not in use can be again readily detached from the instrument proper. It has no declination
arc. The declination of the sun, and the latitude of the place of observation
are both set by the vertical circle of the transit. All settings for position, viz., that
of the polar axis for latitude, that is, for coincidence with the zero marks of the vertical
circle and verniers, and the setting of the declination, are secured by two spirit levels
placed upon the polar axis and upon the solar telescope, as will be seen in the cut.
The degree of precision attainable and the ease of manipulation in the use of this
attachment is commensurate with that of our engineers' and surveyors' transit.
To determine true meridian at any hour of a day, it is only necessary that the
declination and refraction of the sun on that particular day and hour be known to the
observer, and that the polar axis be raised precisely to the co-latitude of the place of
observation.
By the use of our Latitude Level (also attaching to the cross-axis at the side
of the vertical circle, as shown in the second cut), not requiring a reading of the vertical
circle for eveiy setting of the polar axis for latitude except once in a day, observations
can be made repeatedly with speed and accuracy. With the declination and
refraction of the sun previously worked out for the various hours of a day, observations
can be made nearly as fast as a needle can be read of the surveyor's compass.
A concise description of both attachments will be found in our manual. The ac-
companying illustrations of the solar attachment represent them as applied to transits
No. 1 and No. 2. Of all the different kinds in use, we believe it to be the most
efficient. Owing to its position at the side of the transit, it can be easily
manipulated. The adjustments are few and simple, and need to be verified only
from time to time ; besides, they can be readily proved and perfected, being similar to
those in the transit.
Weight of this Solar attachment is 1 lb., that of the latitude level about Ib.
Both are packed in a separate box of mahogany provided with a shoulder strap,
and can also be packed in the box with the instrument.
Price of Solar attachment, as above, with counterpoise, prism with colored
glasses and additional colored glass to apply to the telescope of the transit to
observe the sun's altitude, in order to apply the correction for refraction in
solar transit work, . ...,,.... $85.OO
Price of latitude level, as above, .,.... 15.OO
Surveyors' Solar Attachment (Smith Solar), as used by " General
Land Office of U. S. A.," attached to transits No. 1-s and No. 2-s on pages
162 and 163 as well as the 4^" transit of the same style.
Complete Transits No. 1-s, No. 2-s and No. 4!-s with Smith
Solar, Price, $363.OO