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Your search keyword '"Sriram, Sripadmanaban"' showing total 13 results
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13 results on '"Sriram, Sripadmanaban"'

1. Design and modeling of a tunable spatial heterodyne spectrometer for emission line studies

Author

Kaipachery, Nirmal, Rengaswamy, Sridharan, Sriram, Sripadmanaban, Murthy, Jayant, Ambily, Suresh, Safonova, Margarita, Sreejith, Aickara Gopinathan, Mathew, Joice, and Sarpotdar, Mayuresh

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Spatial Heterodyne Spectroscopy (SHS) is a relatively novel interferometric technique similar to the Fourier transform spectroscopy with heritage from the Michelson Interferometer. An imaging detector is used at the output of a SHS to record the spatially-heterodyned interference pattern. The spectrum of the source is obtained by Fourier transforming the recorded interferogram. The merits of the SHS -- its design, including the absence of moving parts, compactness, high throughput, high SNR and instantaneous spectral measurements -- make it suitable for space as well as for ground observatories. The small bandwidth limitation of the SHS can be overcome by building it in tunable configuration (Tunable Spatial Heterodyne Spectrometer, TSHS). In this paper, we describe the design, development and simulation of a TSHS in refractive configuration suitable for optical wavelength regime. Here we use a beam splitter to split the incoming light compared with all--reflective SHS where a reflective grating does the beam splitting. Hence the alignment of this instrument is simple compared with all--reflective SHS where a fold mirror and a roof mirror are used to combine the beam. This instrument is intended to study faint diffuse extended celestial objects with a resolving power above 20000, and can cover a wavelength range from 350 nm to 700 nm by tuning. It is compact and rugged compared with other instruments having similar configurations., Comment: 26 pages, 16 images, Accepted in Journal of Astronomical Telescopes, Instruments, and Systems

Published
2018

4. The spectroscopic investigation of nebular gas(SING): a dedicated NUV spectrograph to study extended objects

Author

Sriram Sripadmanaban, B. G. Nair, Bharat Chandra, Joice Mathew, Jayant Murthy, Mayuresh Sarpotdar, Shanti Prabha, Margarita Safonova, A. Suresh, R. Mohan, and Nirmal Kaipachery

Subjects
Physics, Payload, business.industry, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Cassegrain reflector, Field of view, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, Optics, law, Astrophysics::Solar and Stellar Astrophysics, CubeSat, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, business, Spectrograph
Abstract

SING is a near ultraviolet (NUV) spectrograph with a size close to 6U CubeSat form-factor. The spectrograph operates in the wavelength range from 1800 A to 3000 A, with a spectral resolution of 2 A at the central wavelength. The spectrograph is intended to operate in low Earth orbit (LEO), with the primary goal to generate spectral maps of the regions of the sky covered within the field of view (FOV) of the instrument, constrained by the orbital inclination of the spacecraft. The payload consists of the telescope in Cassegrain configuration focusing the light on the slit, the corrector lens, the concave grating, the detector, and other required electronics components. As the event rate in the UV is low, the spectrograph employs a photon-counting detector because of its low noise performance. The payload uses FPGA as the main system controller to handle the detector readout, data compression and storage, health monitoring, and telemetry. In this work, we present the optical design and its analysis, along with a brief description of the architecture of electronic subsystems of the payload.

Published
2020
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