19th century Nicol Polariscope or polarimeter, solar observatory
19th century Nicol prisms from a polariscope for solar observations.
Was used to observe the sun.
William Nicol (1770-1851) of Edinburgh developed what is now called the Nicol prism in 1828.
Provenance large French solar observatory.
The prisms are made of Calcite minerals.
Large size calcite prisms.
Complete set: Polariser and Analyser
Not often seen.
"Polariscope or Polarimeter is an instrument for measuring the amount of rotation produced by a substance on the plane of polarisation of plane polarised light. In its simplest, form it would consist of two Nicol's prisms (q.v.); parallel light sent through the first or "polariser" would be polarised in one plane; it then passes through a second Nicol or "analyser." An observer looking through the analyser will have the field of view variously illuminated according to its position. By rotating this Nicol round an axis perpendicular to its plane a point can be reached when all appears dark - i.e. the incident light is completely quenched. If now an "active" substance be put between polariser and analyser, more or less light will get through; by again rotating the analyser the dark position can be rediscovered. The amount of rotation measures the angle through which the active substance has rotated the plane of polarisation. Since it is not easy to be quite certain when the position of absolute darkness is obtained, various devices have been used to avoid the difficulty. The field of view is divided into two parts, and some arrangement is used so that the planes of polarisation of the light are slightly inclined to each other in the two halves. In one case this effect is produced by dividing the analyser into two parts, which are connected together after one of them has been turned end for end. The observer, in using this analyser, rotates it until the two halves are equally dark."
Included in the sale
Polaryser:
Tube diameter: telecope side: 67mm and eyepiece side 70mm
length: 10cm
Size of the prisms: 27x30mm
diagonal: 25mm
Analyser (eyepiece):
Diameter 26mm
length: 47mm
diameter prism: +/- 10mm
Condition
Tested the combination of the Polaryser and the Analyser and you can clearly see the polarisation effect.
The surfaces of the mineral have some oxydation. These seems to be normal with Calcite.
The tubes are in very condition and have signs of use.
Our service
We have been selling vintage astronomical instruments for over more than 10 years.
I'm a amateur astronomer myself and all instruments I sell are in good working condition.
I test all the telescopes under the stars and know the possibilities of each instrument
All the instruments are controlled and cleaned before shipping.
The necessary reparations are done.
If possible missing parts are replaced.
If not, read the item description carefully for possible defects.
Take a close look at the photos.
The advantage is you know exactly what you're buying.
We put a lot of effort in the wrapping of the items.
We use professional shippers for the world wide shipping.
We have experience in shipping large instruments up to the unique and complete 6" Unitron - Polarex
Each shipping has a tracking number.
If wanted the shipping can be ensured door2door
Returns are possible.
The buyer needs to know how to use the instrument in the right way.
There is a limited warranty because we don't sell new instruments but used vintage instruments.
International Buyers
We ship worldwide
We accept Paypal (no charges). Please contact us.
More information
We try to describe the telescope as accurate as possible. If the description isn't clear, please contact us
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