ISRO has released the second AO, inviting proposals from the Indian astronomical community for XPoSat observation time.

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The Indian Space Research Organisation (ISRO) has released the second Announcement of Opportunity (AO), inviting proposals from the Indian astronomical community to analyse data from the XPoSat (X-ray Polarimeter Satellite) mission.ISRO said the mission’s scientific data have been released in the public domain for global scientific use, and that important scientific findings have been published in international peer-reviewed journals.XPoSat is India’s first dedicated X-ray polarimetry mission, aimed at studying the dynamics of astronomical sources under extreme conditions. The mission was launched on January 1, 2024. XPoSat serves as a space astronomy observatory operated by ISRO. The spacecraft is positioned in a 650-km near-equatorial orbit with a six-degree inclination and carries two scientific payloads.The primary payload, POLIX (Polarimeter Instrument in X-rays), measures polarimetry parameters — the degree and angle of polarisation — of medium-energy X-ray photons (8-30 keV) from astronomical sources. The XSPECT (X-ray Spectroscopy and Timing) payload provides spectroscopic and timing information in the 0.8-15 keV energy range.As the second AO is open only to XSPECT-based proposals, observations will be carried out between September 2026 and March 2027.The deadline for submitting proposals under the second AO cycle is July 25. Published - June 22, 2026 07:33 pm IST