Sreekanth Reddy

Senior Research Fellow

Optimizing the GRAVITY interferometer for the observation of faint objects and improving radial velocity measurements of galactic center stars

High Contrast Imaging -- Wavefront Sensing -- Real Time Control -- Direct Imaging -- Adaptive Optics

Current Research Summary:

It is planned to develop an adaptive optics system for a 1-meter class telescope at Vainu Bappu observatory, India. This objective will be realised in two stages. In stage I, a tip-tilt AO system will be developed and tested on telescope. In stage II, a complete AO system (with tip-tilt AO) will be developed and tested on the telescope.

A tip-tilt adaptive optics system is developed and successfully tested on telescope. The instrument is intended to improve the spatial resolution of the image. It is designed for visible band of the electromagnetic spectrum and has resolution of 0.08" with diffraction limited field of view (FOV) of 1.2’. To evaluate the performance of the instrument, it is tested on pair of stars that are separated by few arc-seconds (≈ 2") to several arc-seconds and of magnitude (mv) brighter than 6 in the visible band. The preliminary results have shown an ≈ 47% improvement in image resolution and slightly above 100% improvement in the peak intensity of the image over an integration time of 5 minutes. The instrument is tested for different correction loop frequencies over a field of view of ≈ 1.2" by observing a cluster of stars.

Development of complete AO system (along with tip-tilt AO) as part of stage II is under progress. The instrument will be tested on sky during the second quarter of the year 2019.

Prior Research: