| Abstract : | The detection and characterisation of exoplanets has become an important area of astrophysics in the past two decades, with current efforts mainly focused on exoplanet studies related to atmospheric characterisation, global circulation, habitability and star-planet interaction. Most of these observations require large telescopes, however recent studies have shown that 3-4m class telescopes can also be used for exoplanet atmospheric characterisation. We were also successful in obtaining transmission spectroscopy for a few selected bright targets with the 2m Himalayan Chandra Telescope (HCT, refer to Unni et al., 2022) in the optical domain. In this work, we present observations of exoplanet transmission spectrophotometry of hot Jupiter host stars with HCT. We use both slitless grism spectroscopy and traditional slit spectroscopy to understand the various systematic errors that may impact such observations. Primarily, we explore the systematic error due to air mass, exposure time, atmospheric dispersion and instrument flexure that may cause differential slit losses between the target and reference star. The selected targets are bright and have suitable reference stars of similar spectral type and brightness to avoid major systematic errors. |
