IUCAA Faint Object Spectrograph & Camera (IFOSC) is the main instrument available on the telescope's direct Cassegrain port currently. This instrument was designed along the very successful FOSC model which was developed at the Copenhagen University Observatory for the ESO and Nordic Telescopes. IFOSC employs an EEV 2Kx2K, thinned, back-illuminated CCD with 13.5μm pixels. The spatial sampling scale at the detector is 44μm per arcsecond giving a field of view of about 10.5 arcminutes on the side. In addition to B,V,R,I imaging and photometric capabilities, IFOSC offers a range of grisms with resolutions ranging from 190 to 3700 covering the wavelength region of 350-850nm. Long slit, slitless and Echelle (with cross-disperser) [Echelle mode not available at present] modes are available offering a wide range of observational possibilites.

IFOSC's capabilities are further enhanced with imaging polarimetric as well as spectropolarimetric modes with a reduced field of view of about 2 arcminute radius.

A calibration unit provides a set of lamps for flat field and spectral calibration. A set of three narrow band filters of 8.0nm FWHM, are also housed in the calibration unit. These are particularly suitable for local and red-shifted H-alpha studies, having nominal central wavelengths of 656.3 (T, OD), 660.3 (T, OD), 664.3 (T, OD), 668.3 (T, OD) and 672.3 (T, OD).

Read the notes below before using the exposure time calculator (ETC) for IFOSC.

Special Notes:

  • Currently only 0.8″, 1.0″, 1.5″ and 2.0″ slits are available on IFOSC. With advance requests, it might be possible to provide other slit width options also.

  • The transmission of the telescope is approximately about 80%. This factor should be taken into account while using the Exposure Time Calculator below. Please see here for assumptions made in the calculation.

  • The EEV detector shows fringing in I-band observations and calibration images need to be taken to remove the fringes.




Exposure Time Calculator for IFOSC