The Herschel Science Centre provides the information required for the submission of proposals in the Herschel Space Observatory Web site (http://herschel.esac.esa.int), in collaboration with the ICCs. Astronomers are requested to register to access observatory services, which include the capability to submit proposals, access to the Helpdesk and retrieval of observational data from the Herschel Science Archive.
Proposal preparation and submission is done through the HSpot tool (see Section 6.1, “Introduction to HSpot”), the Herschel Observation Planning Software. A scientific proposal contains at least one AOR, or Astronomical Observation Request. Each AOR is based on an AOT, or Astronomical Observation Template, which is a pre-defined observing mode, characterised by an instrument configuration and way of operation that have been optimised for the execution of a particular type of observation (see Chapter 6, Observing with Herschel). An AOR is generated when the proposer provides the parameters required for the selected AOT to personalise it to his or her individual requirements, and is equivalent to the term "observation" used in this document.
A proposal submitted through HSpot is stored in the Herschel Space Observatory database. The proposer, and co-proposers selected by the principal investigator, are allowed to retrieve, modify and upload their proposal(s) until the closing date of the AO. At that time, the database is closed to HSpot, and the HSC distributes the stored proposals to the HOTAC panels. Proposers can check the status of their proposal(s) in relation to the HOTAC review in the Proposal status Web page (http://herschel.esac.esa.int). During the review process, the HSC provides support to the HOTAC and, on request, assesses the technical feasibility of the observations. In addition, a systematic technical feasibility assessment is carried out on all accepted proposals.
The period of proposal submission before the HOTAC review is called Phase-1. After the HOTAC review results are public, proposal submission Phase-2 starts. In this period, observers are allowed to refine their accepted proposals, modify them following the HOTAC guidelines, and use updated AOTs and the latest available observatory knowledge. Please see the "Herschel Space Observatory Call for Proposals: Policies and Procedures" document for a definition of proposal submission Phase-1 and Phase-2, and for the policies on proposal modifications. The end of proposal submission Phase-2 results in a consolidated database of accepted proposals and its corresponding AORs.
It is sometimes necessary for a PI to modify the AORs even after Phase 2 has ended. Possible reasons include correcting or optimising coordinates, changes of observing strategy as a result of analysing previous observations, forced changes due to instrumental issues that may emerge (the HSC may, from time to time, contact PIs to warn them of instrumental issues that haave been detected and to recommend changes of strategy) and the need to replace targets when the original target is found to be unsuitable in the light of new information.
Minor changes may be made by the PI at any time, although to guarantee that the revised AORs can be scheduled they are required at least 4 weeks and preferably 6 weeks before they are due to be executed to allow time for processing (all new AORs go through technical checks) and to allow for the lead time needed when advance drafts of the schedule are prepared. However, more substantial modifications (e.g. changes of target, or changes of observing mode) must be approved by the Project Scientist before the AORs can be released for scheduling and must, of necessity, be properly justified, with the exact modifications detailed; these changes must be coherent with the original aims of the proposal as approved by HOTAC.