1. Department of Physics, Savitribai Phule Pune University, Ganeshkhind, Pune 411007, India
2. Thüringer Landessternwarte, Sternwarte 5, D-07778 Tautenburg, Germany
3. Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital−263129, India
4. Inter University Centre for Astronomy and Astrophysics (IUCAA), Pune 411007, India
5. Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, Netherlands