| Name: Nitish Singh |
| Affiliation: IIA Bangalore |
| Conference ID: ASI2026_294 |
| Title: Optical Design of a Direct Fibre-Fed MOS with an α–β Fiber Positioner for the 2.34 m VBT |
| Abstract Type: Poster |
| Abstract Category: Facilities, Technologies and Data science |
| Author(s) and Co-Author(s) with Affiliation: Nitish SIngh(IIA Bengaluru) |
| Abstract: We are designing the optical system of a direct fiber-fed, multi-object, medium-resolution spectrograph for the 2.34 m Vainu Bappu Telescope (VBT). The instrument will simultaneously accept light from 100 optical fibers positioned at the telescope’s prime-focus focal plane, which provides a native f/3 beam. An in-house α–β fiber positioner system is being designed and fabricated to accurately place the fibers across the focal plane for efficient multi-object spectroscopy. Each fiber has a core diameter of 100 µm and feeds an f/3 beam directly into the spectrograph, eliminating the need for a traditional entrance slit and improving overall throughput. The spectrograph operates in two channels—blue (350–620 nm) and red (600–1000 nm)—to provide continuous wavelength coverage across the optical band. The design targets a resolving power of R ≈ 3000 in both channels. The expected image quality delivers a full width at half maximum (FWHM) of 2–3 pixels on the detector, where one pixel corresponds to 24 µm, ensuring adequate sampling and stable spectral performance across the full field. |
