Publications from IIAP are submitted here http://hdl.handle.net/2248/1 2026-05-14T16:04:04Z 2026-05-14T16:04:04Z Kapoor, R. C http://hdl.handle.net/2248/8922 2026-05-04T06:12:11Z 2025-09-01T00:00:00Z

Title: The role of three William Herschel telescopes in colonial India Authors: Kapoor, R. C Abstract: In this paper we provide information on some of the telescopes to which one of the most prominent names in the history of astronomy is attached: Frederick William Herschel. He built telescopes of different apertures and focal lengths, the majority being 7-ft or 10-ft focus, and gifted or sold to those interested. We find that at least three 10-ft Herschel telescopes were brought to Calcutta, India, and were used for astronomical observations by British residents and the Christian missionaries in the city. One of these belonged to David Hare, a Scottish watchmaker and philanthrope and the other to James Calder, a prominent merchant of Calcutta. The third one had been gifted by Sir John Herschel to his brother-in-law, Dr. Duncan Stewart, Surgeon in the service of East India Company, in 1834 while Herschel was living at the Cape of Good Hope. In 1844, Dr Stewart presented the telescope to the General Assembly's Institution established by the Bengal Mission of the Free Church of Scotland. We also include in this paper the hitherto unpublished "Herschel Manuscript Catalogue of Stars" visible on the horizon of Calcutta that Sir John had drawn up to accompany the 10-ft telescope, reproduced with the kind permission of the Syndics of Cambridge University Library. The three Indian-based Herschel telescopes are no longer extant. Since 1924 there has been a search for all surviving Herschel telescopes, whether complete, incomplete or missing, but those that were brought to India have yet to be included in these studies-which we hope will now be rectified through this paper. Description: Open Access

2025-09-01T00:00:00Z Kapoor, R. C http://hdl.handle.net/2248/8921 2026-05-04T06:05:38Z 2025-09-01T00:00:00Z

Title: Chasing Mercury: Transit tales from India Authors: Kapoor, R. C Abstract: Planets passing across the disk of the Sun are among the most uncommon and fascinating phenomena in the Solar System. From the Earth, the transits of only Mercury and Venus can be seen. Early on, the transits of Venus were important for precisely determining the scale of the Solar System whereas the transits of Mercury were used to accurately ascertain its orbit and variations in the size of the Sun. This paper presents observations of transits of Mercury made in India from 1651 until 1927 (the last one before Independence in 1947). The observers were East India Company engineers and British officials, European missionaries and geographers and professional and amateur astronomers. In our quest, we stumbled across brief references to the transits of 1753 and 1756 observed by the Jesuit Gaston-Laurent Coeur-doux in Puducherry, and of 1815 by John Hodgson of the East India Company's Bengal Infantry in Dalmau. We also present the unpublished observations of the transit of 1861 made by Norman Pogson at Madras Observatory. Finally, we report on photographs of the 8 May 1924 and 10 November 1927 transits taken at Kodaikanal Observatory as part of their on-going solar physics research. Description: Open Access

2025-09-01T00:00:00Z Shubham Jankiram, Ghatul Mohan, Rekhesh Murthy, J Safonova, M Kumar, P Gopinathan, Maheswar Jain, Shubhangi Mahesh Babu, S http://hdl.handle.net/2248/8920 2026-04-23T03:55:48Z 2025-12-01T00:00:00Z

Title: Near ultraviolet transient explorer (nutex): a cubesat-based nuv imaging payload for transient sky surveys Authors: Shubham Jankiram, Ghatul; Mohan, Rekhesh; Murthy, J; Safonova, M; Kumar, P; Gopinathan, Maheswar; Jain, Shubhangi; Mahesh Babu, S Abstract: The Near Ultraviolet Transient Explorer (NUTEx) is a CubeSat-based nearultraviolet (NUV) imaging payload designed for transient sky surveys and is currently under development. CubeSats are compact and cost-effective satellite platforms that have emerged as versatile tools for scientific exploration and technology demonstrations in space. NUTEx is an imaging telescope operating in the 200–300 nm wavelength range, intended for deployment on a microsatellite bus. The optical system is based on a Ritchey–Chrétien (RC) telescope configuration, featuring a 146-mm primary mirror. The detector is a photoncounting microchannel plate (MCP) device with a solar-blind photocathode, paired with an in-house-developed readout unit. The instrument has a wide field of view (FoV) of 4°, a peak effective area of approximately 18 cm2 at 260 nm, and can reach a sensitivity of 21 AB magnitude (SNR = 5) in a 1200-s exposure. The primary scientific objective of NUTEx is to monitor the night sky for transient phenomena, such as supernova remnants, flaring M-dwarf stars, and other short-timescale events. The payload is currently scheduled for launch in Q2-2026. This paper presents the NUTEx instrument design, outlines its scientific goals and capabilities, and provides an overview of the electronics and mechanical subsystems, including structural analysis Description: Open Access; Open Access Article This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

2025-12-01T00:00:00Z Coude, Simon Stephens, Ian W Myers, Philip C Karnath, Nicole Smith, Howard A Guzman, Andres E Marin, Jessy Zucker, Catherine Andersson, B-G Li, Zhi-Yun Looney, Leslie W Novak, Giles Pillai, Thushara G.S Sadavoy, Sarah Sanhueza, Patricio Archana Soam http://hdl.handle.net/2248/8919 2026-04-23T03:53:02Z 2026-01-01T00:00:00Z

Title: FIELDMAPS data release: Far-infrared polarization in the "bones" of the milky way Authors: Coude, Simon; Stephens, Ian W; Myers, Philip C; Karnath, Nicole; Smith, Howard A; Guzman, Andres E; Marin, Jessy; Zucker, Catherine; Andersson, B-G; Li, Zhi-Yun; Looney, Leslie W; Novak, Giles; Pillai, Thushara G.S; Sadavoy, Sarah; Sanhueza, Patricio; Archana Soam Abstract: Polarization observations of the Milky Way and many other spiral galaxies have found a close correspondence between the orientation of spiral arms and magnetic field lines on scales of hundreds of parsecs. This paper presents polarization measurements at 214 μm toward 10 filamentary candidate "bones" in the Milky Way using the High-resolution Airborne Wide-band Camera on the Stratospheric Observatory for Infrared Astronomy. These data were taken as part of the Filaments Extremely Long and Dark: A Magnetic Polarization Survey and represent the first study to resolve the magnetic field in spiral arms at parsec scales. We describe the complex yet well-defined polarization structure of all 10 candidate bones, and we find a mean difference and standard deviation of −74° ± 32° between their filament axis and the plane-of-sky magnetic field, closer to a field perpendicular to their length rather than parallel. By contrast, the 850 μm polarization data from Planck on scales greater than 10 pc show a nearly parallel mean difference of 3° ± 21°. These findings provide further evidence that magnetic fields can change orientation at the scale of dense molecular clouds, even along spiral arms. Finally, we use a power law to fit the dust polarization fraction as a function of total intensity on a cloud-by-cloud basis and find indices between −0.6 and −0.9, with a mean and standard deviation of −0.7 ± 0.1. The polarization, dust temperature, and column density data presented in this work are publicly available online. Description: Open Access; Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

2026-01-01T00:00:00Z