Table of Contents
Herschel is an observatory mission. Thus, as in ground-based telescopes, the astronomer who is requesting the observations must provide all the information necessary to carry them out. These instructions are known as an "Astronomical Observation Request" (AOR), which is made using a standard Astronomical Observing Template (AOT) (see Section 6.3, “AOT entry”). This information is then converted into spacecraft and instrument commands that are uplinked to the spacecraft to execute the observations. An additional complication with Herschel is that communication with the satellite is normally limited to 3 hours each day, so that all the commands to carry out observations must be uplinked at least 48 hours in advance of the observations being carried out and must be executed autonomously. This means that far more detail must be defined by the observer than for observations in a normal groundbased telescope. The system is designed to make the highly complex process of defining observations as simple as possible for the observer. The following section describes this process.
The astronomer's interface with Herschel is an observation planning program called HSpot. HSpot allows the astronomer to define targets and observations, to calculate the time required and likely s/n and to submit a proposal with the requested observations. At any stage of this process the work in progress can be saved and recovered later. HSpot has been adapted from the original Spitzer Space Observatory SPOT program and thus will be familiar to Spitzer users. The part of HSpot directly adapted from SPOT is known as the "Spot Core" of the program and is maintained by IPAC (about 80%), while the HSC maintains the layer of Herschel-specific functionality (about 20%); HSpot incorporates a total of more than 30 man-years of work between the two centres.
HSpot can be downloaded from the Herschel Science Centre web page at the url:
Alternatively, select the "Tools" option from the left hand menu of the Herschel Science Centre web page and "HSpot download" in the tools page.
HSpot is eminently user-friendly and simple to use and has many functionalities that are of interest even to non-infrared astronomers. New users can generally familiarise themselves with the main functions in an hour or so of simply playing with the program.
HSpot is updated regularly. For the 2011 Guaranteed Time Call, a completely new and revised version was released (HSpot 5.3), including literally dozens of minor and major updates since the previous Open Time Call and also numerous updates to the underlying Spot Core. Version 6.0 was then released for the OT2 Open Time Call; this version has been updated for Phase 2 of OT2 as HSpot 6.1 and will be further updated during 2012 as HSpot 6.2, which will be the final major release of HSpot. Occasionally, unexpected issues come to light requiring a new update of HSpot, in which case a new release is made that will be downloaded automatically from the HSC. For each new Call and at key points between Calls a new version of HSpot has been made available with any necessary updates: the default is that HSpot will download these updates automatically and offer them to you. It is strongly recommended that you do not change this option, as it may lead to submitting or revising your AORs against a wrong HSpot version, or to having incorrect time estimates for your AORs (in extreme cases it could even lead to your proposal being rejected automatically).
Each time that you open HSpot, it will connect to the HSC server and check to see if a new version is available. If one is found, you will be offered a choice of closing HSpot immediately and re-opening it with the new version, of waiting to install the new version, or of refusing the update (in which case automatic updates are disabled in the future). You are strongly advised to accept the update immediately; normally it will be installed and operational in under a minute.
Similarly, occasionally a new time estimator version may be announced when you open HSpot; the time estimator links your AORs to the latest instrument control software that sets the parameters for each observation. Normally time estimator changes will not affect the duration of observations now, but will effect essential parameters in the set-up of observations. When the time estimator version is updated, the time estimate for your previously prepared AORs will be shown in red; it is essential to submit your proposal against the latest time estimator version - to do this, just re-run time estimation before submission so that all the time estimates are shown in black font.
HSpot has been developed to run on the three main operating systems currently in use: Unix/Linux, Windows and Mac. The development work has been carried out on Solaris and ported to these operating systems and the system has been extensively tested and used operationally by many hundreds of users for some five years. We thus know that HSpot should run reliably on all the principal operating systems available to users. For each operating system certain common platforms are supported. Users are strongly urged to use these standard combinations of operating system and platform, as no guarantee can be offered that HSpot will run correctly on other combinations and no guarantee can be made of support for other platforms; occasional serious issues have been reported with other platforms, particularly for Linux users due to the wide variety of platforms available for Linux (it is physically impossible to test or to support all possible Linux platforms). Similarly, users will understand that, for example, the Windows version of HSpot has been extensively tested on Windows XP, Vista and Windows 7, but was developed with Windows XP.
Detailed information on the operating systems and platforms supported can be found in the HSpot manual. HSpot runs under Java and users are strongly advised to ensure that all updates and patches of their operating system are installed.
|HSpot will only run on Java 1.6 and later. Older Mac machines that do not support a Dual Core and 64-bit architecture will not install HSpot. Due to the way that Mac handles Java, Mac users have occasionally experienced minor problems with HSpot that Windows, Solaris and Linux users have not.|
Proposal presentation is extremely simple with HSpot. Once the observations to be carried out are defined and saved, the proposal can be submitted quickly and easily from the "Tools" menu. A submitted proposal can be retrieved before the deadline for submission and revised as many times as required; this allows you to submit a draft and then update it continuously so that, even in case of disaster (your local hard disk fails, the Internet falls over just before the submission deadline, etc), HSC will always have a valid latest version of the proposal. To submit a proposal, apart from the AORs (that is, the source information, instrumental configuration, exposure time, etc. for each object to be observed) the proposer needs a text file with the proposal abstract (maximum 2000 characters, including spaces), which can be read in directly, a PDF file of the scientific justification (limited to a maximum of 5Mbt and prepared with the latest version of the HerschelFORM PDFLatex package that is available on the Herschel Science Centre webpage) and to give basic information such as the proposal title, list of co-Is and the observing call that the proposal is responding to.
When a proposal has been submitted, HSpot will confirm that it has been transmitted correctly and, on completion of processing, an e-mail will be received from the HSC Proposal handling System confirming its successful receipt.
The time taken to generate and transmit the acknowledgement e-mail is a strong function of the system load. When the HSC servers are heavily loaded close to a call closure, the acknowledgement e-mail may take tens of minutes or even, in extreme cases, a few hours to arrive. Until this e-mail is received, you will not be able to retrieve and update the latest version of your proposal. All proposals to arrive are logged with time of submission and the HSC will know that your proposal is in the system, even if you have not yet received the formal acknowledgement.
Now that formal Calls for Proposals have ended the load on the system is normally extremely low and a proposal should be acknowledged rapidly. However, proposals will large numbers of HIFI observations, especially Spectral Scans, are much slower to process than PACS or SPIRE photometry proposals and make take some minutes to be processed and acknowledged.