Preprint

Modelling the Point Spread Function of ILMT images

Naveen DukiyaMahatma Jyotiba Phule Rohilkhand University , Pilibhit Bypass Road , Bareilly 243006 , Uttar Pradesh , IndiaBhavya AilawadhiPhysical Research Laboratory , Navrangpura , Ahmedabad , Gujarat - 380009 , IndiaTalat AkhunovNational University of Uzbekistan , Department of Astronomy and Astrophysics , 100174 Tashkent , UzbekistanMonalisa DubeyAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak , Nainital - 263002 , IndiaSara FilaliInstitute of Astrophysics and Geophysics , Liège University , Allée du 6 Août 19c , 4000 Liège , BelgiumPaul HicksonDepartment of Physics and Astronomy , The University of British Columbia , 6224 Agricul- tural Road , Vancouver , BC V6T 1Z1 , CanadaPriyanshi KumariAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak , Nainital - 263002 , IndiaGokul Singh MehraAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak , Nainital - 263002 , IndiaKuntal MisraAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak , Nainital - 263002 , IndiaVibhore NegiKavli Institute for Astronomy and Astrophysics , Peking University , Beijing 100871 , ChinaKumar PranshuAryabhatta Research Institute of Observational Sciences (ARIES) , Manora Peak , Nainital - 263002 , IndiaJean SurdejInstitute of Astrophysics and Geophysics , Liège University , Allée du 6 Août 19c , 4000 Liège , BelgiumSarvesh Kumar YadavAyush GuptaMahatma Jyotiba Phule Rohilkhand University , Pilibhit Bypass Road , Bareilly 243006 , Uttar Pradesh , India

2026

Ochiq kirishYashil

ABI

Annotatsiya

We have devised an approach to model the empirical Point Spread Function (PSF) of the images taken with the 4-meter International Liquid Mirror Telescope (ILMT). The characteristics of the ILMT PSF are influenced by the nature of the Liquid Mirror, as well as by instrument specific and atmospheric factors. As the telescope uses Time Delay Integration (TDI) mode for tracking the passing objects, the PSF varies along the declination axis due to differential motion and star-trail curvature. The 5-element optical corrector homogenizes the PSF to some degree, but does not completely eliminate the disturbing effects mentioned above. The PSF in the RA direction is changing due to the sky conditions. We show that we can successfully model the PSF of 4k$\times$4k chunks using PSFEx, accounting for second-order X-Y variability. Our software robustly reproduces the PSF and its variation across the field.

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Identifikatorlar

DOI: 10.48550/arxiv.2610.14819

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