Abstract Details
| Name: Sriram Affiliation: Indian Institute of Astrophysics Conference ID: ASI2015_1056 Title : Ground calibration of the UVIT Authors and Co-Authors : Annapurni Subramaniam (IIA), K. Sankarasubramanian (ISAC), P.U. Kamath, S. Kathiravan, Amit Kumar, P.K. Mahesh, S. Nagbhushana, S.N. Tandon (IIA), S. K. Ghosh (NCRA) Abstract Type : Oral Abstract Category : Instrumentation and Techniques Abstract : The Ultra-Violet Imaging Telescope (UVIT) onboard ASTROSAT, India's multi-wavelength astronomical satellite, is configured as twin telescopes each of ~38 cm aperture. One telescope observes in the Far-ultraviolet(FUV; 130-180 nm), and the other telescope observes in the Near-ultraviolet (NUV; 200 - 300 nm) and the Visual (VIS; 320 - 550 nm) bands. Simultaneous imaging in all the three bands is possible over a field ~ 28' diameter. The spatial resolution is < 1.8" FWHM. For optimum performance of UVIT over the range of wavelengths from FUV through the optical band, centres of the fields in the three bands need to be aligned to better than 1 arcmin. As there is no possibility of readjusting the focus in orbit, it is required that the focii are adjusted optimally. Various experiments were carried out to characterise the overall performance of UVIT such as (i) PSF determination, (ii) thermal effects on PSF, (iii) scattering of the telescope, (iv) relative alignment of the telescope, (v) determination of the sensitivity of UVIT, (vi) ground calibration of the gratings and filters and (vi) determination of the QE and distortion patter of the detector. Details of these experiments and their results will be presented. |