1. Introduction and Schedule

AstroSat is the first dedicated Indian astronomy mission aimed at studying celestial sources in X-ray, UV and limited optical spectral bands simultaneously, thus providing a space astronomy observatory which is operated by the Indian Space Research Organisation (ISRO).  The satellite is at 650 km near-equatorial orbit with 6-degree orbital inclination.

AstroSat completed one year and six months in orbit.  Currently, the second AO cycle proposals are being executed.

The details on the mission and payloads are available in the ISRO website.  The technical details of payloads are described in the AstroSat Handbook.

A significant amount of AstroSat’s observing time is made available to PIs of proposals.  The availability of AstroSat time will be made through Announcements of Opportunity (AO).  Electronic submission of proposals through AstroSat Proposal Processing System (APPS) software at ISSDC website will be required to submit a proposal in response to this AO.  Submitted proposals will be reviewed by the AstroSat Time Allocation Committee (ATAC) and AstroSat Technical Committee (ATC) for scientific merit and technical feasibility.

The observations will be planned as per mission scheduling.  The PI will be informed, after the completion of successful observation for the downloading of processed Level-1 data.  After the 12 months proprietary period, which starts from the day Level-1 is made available to the PI, the archived data will be open to registered users and will be available in ISSDC.

This AO soliciting proposals for the third AO cycle is for Indian as well as international proposers as Principal Investigators (PIs) to utilise AstroSat observatory time.  The observations will be carried out in the period between October 2017 to September 2018 (approximately one year). 

 All announcements regarding exact dates and proposal submission will be from the Indian Space Science Data Centre (ISSDC) website ( and AstroSat Science support Cell (ASC) websites (

For all matters related to a proposal, the Principal Investigator (PI) of the proposal is the single point of contact for ISRO.   The PI will be informed through e-mail about the status of the submitted proposals. It is expected that necessary facilities for carrying out the AO project will be provided by respective host institutions. 

The deadline for submission of proposals will be announced in ISSDC and ASC websites.