India-TMT project—science instrumentation program

Sethuram, Ramya; Sriram, S.; Divakar, Devika; Surya, Arun; Varshney, Hari Mohan; Kambala, Sudarshan; Hasan, Amirul; Prakash, Ajin; Govinda, K. V.; Viswanatha,; Anupama, G. C.; Maheswar, G.; Ojha, D.; Pandey, J.; Manoj, P.; Ramaprakash, A. N.; Reddy, Bacham E.; Shah, Sarang S.; Srianand, R.; Subramaniam, Annapurni; Subramanian, Smitha

doi:10.1007/s12036-022-09867-y

Cited by 2 publications

(1 citation statement)

References 20 publications

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“…We have applied the IAH to a segmented aperture similar to that used in the Thirty Meter Telescope (TMT; Nelson & Sanders 2008 ;Sch öck et al 2009 ;Cole 2017 ), one of the largest and most technologically advanced telescopes in the world. Scheduled for construction at Mauna Kea, Hawaii, USA, and it is planned that the telescope will MNRAS 523, 5442-5451 (2023) have its first light in the early 2030s, this ground-based astronomical observatory is a collaborative effort among astronomical communities from India, Canada, China, Japan, and the United States, who are jointly determining the scientific goals, array of instruments, and o v erall design of the TMT observ atory (Si v arani et al 2022 ). The observatory boasts a 30-m diameter segmented mirror, comprising 492 hexagonal elements, each with a corner-to-corner measurement of 1.44 m. These segments are meticulously arranged, maintaining a mere 2.5 mm gap between them (Nelson & Sanders 2006 ).…”

Section: Tmt Aperturementioning

confidence: 99%

Interferometric apodization by homothety – I. Optimization of the device parameters

Chafi

Azhari

Azagrouze

et al. 2023

Monthly Notices of the Royal Astronomical Society

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This study is focused on the very high dynamic imaging field, specifically the direct observation of exoplanetary systems. The coronagraph is an essential technique for suppressing the star’s light, making it possible to detect an exoplanet with a very weak luminosity compared to its host star. Apodization improves the rejection of the coronagraph, thereby increasing its sensitivity. This work presents the apodization method by interferometry using homothety, with either a rectangular or circular aperture. We discuss the principle method, the proposed experimental setup, and present the obtained results by optimizing the free parameters of the system while concentrating the maximum of the light energy in the central diffraction lobe, with a concentration rate of 93.6% for the circular aperture and 91.5% for the rectangular geometry. The obtained results enabled scaling the various elements of the experiment in accordance with practical constraints. Simulation results are presented for both circular and rectangular apertures. We performed simulations on a hexagonal aperture, both with and without a central obstruction, as well as a segmented aperture similar to the one used in the Thirty Meter Telescope (TMT). This approach enables the attainment of a contrast of approximately 10−4 at small angular separations, specifically around 1.8λ/D. When integrated with a coronagraph, this technique exhibits great promise. These findings confirm that our proposed technique can effectively enhance the performance of a coronagraph.

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Section: Tmt Aperturementioning

confidence: 99%

Interferometric apodization by homothety – I. Optimization of the device parameters

Chafi

Azhari

Azagrouze

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Atmospheric dispersion corrector for a multi-object spectroscopic mode of HROS-TMT

Bestha,

Hasan,

Divakar

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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Highly multiplexed spectroscopic surveys have changed the astronomy landscape in recent years. However, these surveys are limited to low and medium spectral resolution. High spectral resolution spectroscopy is often photon starved and will benefit from a large telescope aperture. Multiplexed high-resolution surveys require a wide field of view and a large aperture for a suitable large number of bright targets. This requirement introduces several practical difficulties, especially for large telescopes, such as the future ELTs. Some of the challenges are the need for a wide field atmospheric dispersion corrector and to deal with the curved non-telecentric focal plane. Here we present a concept of Multi-Object Spectroscopy (MOS) mode for TMT High-Resolution Optical Spectrograph (HROS), where we have designed an atmospheric dispersion corrector for individual objects that fit inside a fiber positioner. We present the ZEMAX design and the performance of the atmospheric dispersion corrector for all elevations accessible by TMT.

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India-TMT project—science instrumentation program

Cited by 2 publications

References 20 publications

Interferometric apodization by homothety – I. Optimization of the device parameters

Interferometric apodization by homothety – I. Optimization of the device parameters

Atmospheric dispersion corrector for a multi-object spectroscopic mode of HROS-TMT

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