Design of TFOSC Compatible Polarimeter for Polarimetric Observations

PIERS 2014, Guangzhou, China, 25 - 28 August 2014, vol.2, no.1, pp.1591-1594, (Full Text)

This study proposes a design steps of a TFOSC (TUG Faint Object Spectrograph

and Camera) focal plane instrument compatible optical polarimeter in order to investigate the

physical parameters of targets (such as albedo, diameter, taxonomy of asteroids, porosity) based

on the polarization properties of light. TFOSC has been used in order to determine the re?ection

spectroscopy and taxonomy of the asteroids, during the last observation campaign of Apophis’s

close approach with 1.5m diametertelescope RTT150 at TUG. Since the brightness of object is

fainter than 17th magnitude and the class of asteroid detection limit is 16th magnitude with

RTT150 telescope, more observation time is required. Asteroids are the rigid rock objects which

change the energy distribution of sun beams that impinge on Asteroids and re?ect by polarizing

them. This emerging variation strictly depends on the physical properties of asteroids such as

albedo, diameter, shape, chemical structures, surface geometry and porosity. Meanwhile, images

captured with Polarimeter will be free of the atmospheric e?ect and device errors.

WeDoWo (Wedged Double Wollaston) prism is one of the methods used for determining the

celestial body originated light polarization rate throughout the world wide observatories. The

light impinging on WeDoWo prism is divided into four di?erent images which is polarized at 0?,

45?, 90?, 135? and used to determine Stokes’ parameters of electromagnetic waves. First three

elements of Stokes’ vector can be determined without needing neither simultaneously obtained

light component that haveλ/2 variation nor other moving components.WeDoWo prism has been

and has a thickness of 18mm.