ISRO

2. Observing cycles

In this third AO cycle, 45% of observing time is available for Indian AO proposals and 10% of observing time is for International AO proposals.  5% time is allotted for Targets of Opportunity (ToO).  Rest of the 40% time in this cycle is allotted for payload teams and calibration.

2.1       AO cycle

AstroSat is operated in a pre-planned manner i.e proposers are not present at Mission Operations Complex during the execution of their observations.  Thus, all observations must be specified in full details in advance.

  • The percentage of observing time for executing AO proposals during October 2017 – September 2018 is 60% and is termed as third AO cycle.
  • Out of 60%, 45% time is exclusive for Indian proposers as Principal Investigators (PIs) to utilise AstroSat observatory time. They could be interested  researchers, scientists and astronomy community at large, involved in scientific research in the field of astronomy and are equipped to submit proposals as Principal Investigators (PIs) for specific target observations with necessary scientific and technical justification and can analyse the data, if the target is observed based on approvals. In addition, 10% of the time is for international proposers from the global astronomy community.  Remaining 5% of time is for ToO proposals (see 2.2).
  • In order to expand the AstroSat user community, it  is  recommended  that those  who  are  submitting proposals  as  PIs  in Guaranteed Time (GT)  cycle, encourage  other astronomers  to be  PI  in AO  proposals. If a proposer from a university, college or any institution submitting a proposal under AO cycle wishes to have a   Co-I from any payload teams to get help in data analysis or needs support on science related issues, he/she may do so in consultation with the payload team leads as provided in the handbook.
  • All the selected AO proposals will be inserted into the observing schedule.  However, few observations approved in this AO cycle may be scheduled outside of the above period, in case there is operations requirement, which will be provided by AstroSat Mission.
  • Proposers are requested not to duplicate any of the planned observations and should carefully justify duplications if any, with performed observations. Proposers have to check the list of objects and instrument parameters for observations already/ being carried out using AstroSat. A Red book containing these targets will be made available in the ISSDC website. Proposers wishing to observe any of these targets should justify why it is important to do so and what additional information will come from the proposed observations. See also section 4.
  • Checks for duplications will be performed by ATAC while processing the proposals during the scientific review.

2.2       Targets of Opportunity (ToO) cycle

  • Proposals that require observation of phenomenon like outburst of a supernova or nova, observation of a new transient source or X-ray nova or study of characteristics of a source when it makes transition to a different state etc. and for which one cannot predict in advance the time of occurrence, must be submitted as ToO proposal and they will be reviewed by a separate ToO Committee.
  • A ToO cycle is always open for submitting proposals. A provision of 5% observing time is reserved for ToO proposals. 
  • Data of observations made using a ToO proposal during the allotted ToO time will be made public immediately. 
  • If this time is not fully subscribed, it may be added to the time for the AO proposals.
  • Anticipated ToOs are ToOs whose source position is known but time of observation is not known or unpredictable.  The proposal for anticipated ToOs can also be submitted through APPS, which will be reviewed by ATAC committee.  The scientific justification needs to be really strong to clear the proposal and also has to get priority “A” for acceptance (refer APPS proposer's guide available in ASC website for details on anticipated ToOs and priority ranking for proposals).  However  when  the event occurs,  a  ToO  trigger  proposal  by  the PI  of  the original proposal has  to be  submitted under ToO  cycle to schedule the proposal. The data rights are same as that for AO proposals.