orac000-garl Version: 06 Created: 22 February 1999 Modified: 22 February 1999
This document contains the ORAC project glossary and reference list.
This document attempts to provide a glossary of all of the acronyms, abbreviations and terms used in the ORAC project documents. It also provides a list of all of the other documents referenced in these documents, and of other relevant documents. The purpose of this is to save repeating these list in each document produced.
New references and definitions will be added to this document as required. It is recognised that as new references are added they cannot be kept in alphabetic order as the reordering would require cross-references from other documents to be updated. However, some attempt at organisation is made by separating the documents into categories, giving each a separate number list.
As the project has developed some of the terms used to describe items and functions have changed. For example the adoption of the Gemini OT as the observation preparation system in ORAC has led to the adoption of a number of terms deriving from it. We have tried to idetify such dual terms in the glossary, but it may be incomplete.
ADAM | Astronomical Data Acquisition Monitor, the distributed tasking system in use at UKIRT and at other UK connected telescopes, and by Starlink. This comes in a VMS flavour and a Unix flavour (also in Perkin-Elmer and Transputer flavours of less relevance). |
ALICE | Array Limited Infrared Control Environment |
CAD | Command Action Directive |
CAR | Command Action Response |
Chained | Observations are "chained" in the OT to indicate that they must be carried out sequentially, but not necessarily consecutively |
Chooser | The ORAC software that allows the user to choose which Observation to carry out next, and which provides the user interface to the Sequencer. |
CHOP | A mode in which exposures are secured at two adjacent positions on the sky by chopping and in which the array is read only at the end of each exposure. |
chopping | The process of switching the telescope pointing between two adjacent points on the sky by movement of the chopping secondary mirror, the "chopper". |
CICS | The Gemini Core Instrument Control System |
Classical | The form of observing which is current practice at UKIRT, whereby an observer is awarded a block of time in which to observe. |
Config | The ascii file that contains a description of the required instrument configuration ( filters, exposure times etc.), and which is used by the ICS |
DHS | Data Handling System - or the system that is responsible for storage and rapid display of data acquired, and for other such "data handling". Depending on context this might be the Gemini DHS or the UKIRT DHS. |
DRAMA | The AAO tasking system that has carried on where ADAM left off. |
Edict | EDinburgh Infrared ConTrol. The next generation of ALICE. |
EPICS | Experimental Physics and Industrial Control System |
EXEC | EXECutable procedure - the description of the required sequence of instrument configurations, telecope moves, exposures, which is used by the Sequencer (ORAC) or ICS (current). |
exposure | The interval between resets of the array. Depending on the current mode, the buildup of charge on the array may be read once or several times during this period. |
Flexible Scheduling | Observatory operations in which an attempt is made to schedule individual observations for numerous users on any given night, according to required conditions, in order to maximise the science output of the telescope. |
Frame | A data frame, or the acquisition thereof. Perhaps used inconsistently, and roughly equivalent to an integration in the current UKIRT system. |
Grouped | Observations are grouped in the OT to indicate that they must be Scheduled as a single un-interruptible block, with any relative order. |
ICD | Interface Control Document |
ICS | Instrument Control System |
Instrument Configuration | The same as Config. |
integration | A sequence of one or more exposures. Data within an integration is combined in the detector software system and returned as a single dataset to the host. The exposures may be made in a single beam or in two beams, depending on the mode. The result of a single OBSERVE command. |
mode | One of STARE, ND_STARE, CHOP, ND_CHOP, and similar UFTI terms. |
ND_CHOP | A mode in which exposures are secured at two adjacent positions on the sky by chopping, and in which the array is read several times during each exposure. |
ND_STARE | A mode in which exposures are performed at a single target position on the sky (i.e. not chopping) and in which the array is read several times during each exposure. |
Observation Sequence | The sequence of telescope movements and integrations used to obtain an observation of a source. |
observation | A sequence of one or more integrations secured on the same target object. In this definition is roughly equivalent to a group. (Not quite the same as Observation in OT terminology, but closely related subset - see next item) |
Observation Definition | Also called Observation in some documents, and in particular by the OT. The electronic description of the instrument configuration, target details, sequence, required conditions for the observation of a single astronomical target. It is the smallest schedulable unit. |
Observation Database | The database of Science Programmes and Observations which have been created using the OT and submitted to UKIRT. |
Observation Scheduler | Those aspects of the Scheduler which are concerned with calculating an Observing plan for a night. |
Observation Preparation System | The tool used by the users for phase-2 input. For the ORAC system this is the same as the OT. For the current system it refers to UKIRT_PREP |
Observing Mode | The mode into which an instrument (or ICS) is put for an Observation. Thus for an OBSERVE command an ICS will be in a single Observing Mode and everything required to acquire the data at that stage must be handled by the ICS. |
Observing Tool | Originally the Gemini Observing Tool, there is now also a version for UKIRT in development. The Phase 2 preparation system. |
Observing Plan | Ordered list of targets to be observed on a given night, prepared by the Scheduler |
ORAC-DR | The ORAC pipeline data reduction system |
OCS | Observatory Control System. The system that has overall control of observing at the Observatory, in charge of the other systems. Depending on context this may be the Gemini OCS or the UKIRT OCS. |
OT | Short for the Observing Tool (Gemini or UKIRT version). |
PATT | Panel for the allocation of telescope time |
Phase -1 | Proposal submission by the observer, proposal information |
Phase -2 | The detailed definition of required Observations for accepted proposals. |
Plan | short from of Observing Plan or Semester Plan |
Program(me) | short form of Science Program(me) |
Queue | The Observing Plan - the ordered list of Observations to be executed sequentially. |
Queue Scheduled | Flexibly scheduled observing implementation in which the Observations to be carried out are sorted into a queue based on their requirements and priority. |
Recipe | description of the steps for reducing data in ORAC-DR |
Science Programme, Science Program | All the observations required for all the sources a PI has been awarded time for. In general 'programme' is used to refer to the human concept and 'program' to the electronic version - ie the output of the OT for several targets. (but this may not be consistent in older documents). |
Semester Plan | Plan for a semester of flexible and classical observing, as prepared by the Scheduler |
Service | The current UKIRT service programme. |
Scheduler | Software to create nightly Observing Plans, and analyse Semester Plan |
Script | Sometimes a general term, sometimes referring to an ORAC-DR script. |
SGML | Standard Generalised Markup Language |
SIR | Status and Information Record |
STARE | A mode in which exposures are performed at a single target position on the sky (i.e. not chopping) and in which the array is read only at the end of each exposure. |
Strategic Scheduler | Those functions of the Scheduler which are concerned with keeping track of/ analysing the distribution of allocations for a semester. |
Target Description | Information describing the target: co-ordinates, guide star location |
TAG | (UKIRT) Time Allocation Group |
TCS | Telescope Control System |
userid | The users chosen name which is used as the name of the sub-directory in which their Configs and EXECs are stored. (usually the users initials) |
VxWorks | A real time operating system from Wind River. |
XML | eXtensible Markup Language |
References to documents in the ORAC project.
References to documents produced as part of the Michelle project.
References to documents produced as part of the Gemini project.
References to other documents.