Debris finder, PolCor-2
An instrument to detect debris around young stars

Content:

1. Introduction
2. Exoplanets
3. Stars dust disc
4. Albanova, research center in Stockholm
5. The instrument, PolCor-2
6. The mechanical box's surfaces
7. Coronagraph
8. Mirror set one
9. Filters
10. Lyot Stop
11. Servo motors
12. Polarizer
13. Parabolic and flat mirror set two
14. Lucky Imaging
15. The camera
16. The computer
17. Test of the instrument that has been done
18. Conclusion
19. End of demonstration
20. Follow up with links of information about coronagraphs

12: Polarizer

The system includes a polarizer, here did you also got the other part of the instrument's name, Pol of PolCor-2. Its task is to filter out the polarization angle that is most beneficial. Often the angle that give as high contrast as possible. By rotating this filter and analyze the data (image) obtained as a quality measure it can be used to obtain the optimum angle.

Polarizer is visible in the image above as the device that follows the Lyot Stop filter. Also this is provided with a servo motor that transfers torque through a timing belt. The servomotor sets quickly filter into the angles of 0, 45, 90 and 135 degrees. It also has a position where it blocks the light path. The final image may consist of several combinations of angles. The polarizer is designed to let through the wavelength range from 410 nm to 750 nm.

• https://en.wikipedia.org/ wiki/Polarization_in_ astronomy (Polarization in astronomy, Wiki)