Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/4731
Title: On the performance of a dual-beam polarimeter at Kodaikanal tower telescope
Authors: Nagaraju, K
Sankarasubramanian, K
Rangarajan, K. E
Ramesh, K. B
Singh, J
Devendran, P
Hariharan
Keywords: Instrumentation: Polarimeter
Issue Date: Sep-2008
Publisher: Astronomical Society of India
Citation: Bulletin of the Astronomical Society of India, Vol. 36, No. 2 & 3, pp. 99 – 110
Abstract: Calibration and characterization of a dual-beam polarimeter installed at Kodaikanal Tower Telescope (KTT) for spectropolarimetric observations are presented in this paper. It was found that a slit width of 48 μ is optimum for the spectrograph setup at KTT and corresponding spectral resolution is 32.47 m\AA. It was demonstrated that the precision in polarization measurement can be achieved better than 0.1 % by increasing the exposure time. However, the polarimetric calibration accuracy is limited to 0.35% for Stokes Q and U parameters and 0.2% for Stokes V parameter, mainly due to the uncertainty in the retardance of the calibration retarder. A comparison of the magnetic field measurement between the Solar Optical Telescope (SOT) onboard Hinode and KTT for an active region was made and a good match was found after spatial smearing of Hinode/SOT measurements by 5.12''.
URI: http://hdl.handle.net/2248/4731
ISSN: 0304-9523
???metadata.dc.rights???: © Astronomical Society of India
???metadata.dc.relation.uri???: http://www.ncra.tifr.res.in/~basi/08JunSep/BASI_ABS/36992008.htm
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