Doc. 9.5, Ver. 1.0 | March 2022 ALMA Observing Tool User Manual Andy Biggs, Rein H. Warmels ALMA,aninternationalastronomyfacility,isapartnershipofESO(representingitsmemberstates),NSF(USA) andNINS(Japan),togetherwithNRC(Canada),MOSTandASIAA(Taiwan),andKASI(RepublicofKorea),in cooperationwiththeRepublicofChile. TheJointALMAObservatoryisoperatedbyESO,AUI/NRAOandNAOJ. Forfurtherinformationortocommentonthisdocument,pleasecontactyourregionalHelpdeskthroughtheALMAUser Portal at www.almascience.org. Helpdesk tickets will be directed to the appropriate ALMA Regional Centre at ESO, NAOJorNRAO. Version Date Editors 0.5,Ver. 1.0 March2011 ReinWarmels 0.5,Ver. 1.1 August2011 ReinWarmels 1.5,Ver. 1.0 May2012 ReinWarmels 1.5,Ver. 1.1 October2012 AndyBiggs 1.5,Ver. 1.2 February2013 AndyBiggs 1.5,Ver. 1.3 February2013 AndyBiggs 2.5,Ver. 1.0 October2013 AndyBiggs 3.5,Ver. 1.0 March2015 AndyBiggs 4.5,Ver. 1.0 March2016 AndyBiggs 4.5,Ver. 2.0 May2016 AndyBiggs 5.5,Ver. 1.0 March2017 AndyBiggs 5.5,Ver. 2.0 June2017 AndyBiggs 6.5,Ver. 1.0 March2018 AndyBiggs 7.5,Ver. 1.0 February2019 AndyBiggs 7.5,Ver. 2.0 June2019 AndyBiggs 8.5,Ver. 1.0 January2020 AndyBiggs 8.5,Ver. 1.1 March2020 AndyBiggs 8.5,Ver. 1.2 March2021 AndyBiggs 9.5,Ver. 1.0 March2022 AndyBiggs TheALMAOTTeam,andthemanyTesters. Inpublications,pleaserefertothisdocumentas: ALMAObservingToolUserManual,ALMADoc. 9.5,Version1.0 Contents 1 Introduction 5 1.1 How to Use this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 User Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3 Release Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Credits and Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Install and Run the Observing Tool 7 2.1 System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1 Java . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.2 Supported Platforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1.3 Disk Space and Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1.4 Mac Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Using the OT Installer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1 Mac Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.2 Linux Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.3 Windows Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Tarball Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.2 Starting the OT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.4 Connecting Through a Proxy Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Basic Concepts 11 3.1 Phase-1 Proposals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 DDT Proposals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3 ACA Supplemental Call Proposals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.4 Stand-alone ACA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.5 Phase-2 Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.6 Science Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.7 Observing Unit Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.8 Scheduling Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.9 Project Submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.10 Project Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.11 AOT files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.12 Project Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4 Overview of the Observing Tool 17 4.1 Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.2 The OT Main Graphical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.2.1 GUI Parameter Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.2.2 GUI Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2.3 Menu and Toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2.4 The OT Panes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2.4.1 The Project Structure Pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2.4.2 The Editors Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1 4.2.4.3 The Feedback Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.2.4.4 The Overview Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.3 OT Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5 Phase 1 – Observing Proposal 23 5.1 Open a Phase-1 Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.2 The Proposal Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2.1 Adding Investigators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2.2 Reviewer Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.2.3 Scientific Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.2.4 Management Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.2.5 Duplicate Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3 Adding Phase-1 Science Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3.2 Field Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3.2.1 Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3.2.2 Source clustering/Psuedo-Science Goals . . . . . . . . . . . . . . . . . . . . . . . 27 5.3.2.3 Resolving source information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.3.2.4 Expected Source Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.3.2.5 Field definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.3.2.6 Solar total-power observing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.3.2.7 Import/Export of Source Information . . . . . . . . . . . . . . . . . . . . . . . . 29 5.3.3 Spectral Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.3.3.1 Spectral Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.3.3.2 Recovering image sidebands at Bands 9 and 10 (90-Degree Walsh Switching) . . 30 5.3.3.3 Polarization Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.3.3.4 Spectral-window placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.3.3.5 Spectral Line – one spectral window per baseband . . . . . . . . . . . . . . . . . 32 5.3.3.6 Spectral Line – more than one spectral window per baseband . . . . . . . . . . . 32 5.3.3.7 Spectral Line – VLBI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 5.3.3.8 Representative Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 5.3.3.9 Single Continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.3.3.10 Spectral Scan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.3.3.11 Multiple velocities and tuning solutions . . . . . . . . . . . . . . . . . . . . . . . 35 5.3.3.12 Rest Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 5.3.4 Calibration Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.3.4.1 User-defined calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.3.4.2 Astrometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.3.5 Control and Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.3.5.1 Imaging considerations: arrays and configurations . . . . . . . . . . . . . . . . . 37 5.3.5.2 Sensitivity considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.3.5.3 Time Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.3.5.4 Differential Gain Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.3.5.5 Solar and VLBI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.3.5.6 Overriding the OT’s time estimate . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.3.5.7 Simultaneous observing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.3.5.8 Time-constrained observing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.3.6 Technical Justification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.4 Summary Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.5 Proposal Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.6 Proposal Submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2 6 Phase 2 – Observing Program 45 6.1 Generation from Science Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.1.1 Phase-2 Science Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.1.2 Scheduling Block Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.2 Observing Program Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.2.1 Observing Unit Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.2.2 Scheduling Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.2.3 Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 6.2.4 Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 6.2.4.1 Field Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 6.2.4.2 Instrument Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 6.2.4.3 Observing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 6.2.5 Observing Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 7 Tools 55 7.1 The ALMA Template Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 7.2 Sensitivity Calculator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 7.3 Spectral Line Picker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 7.4 Archive Search Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.5 Calibrator Selection Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.6 LO Configuration Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 8 The Visual Spatial Editor 61 8.1 Overview of the Graphical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 8.2 Creating a Field Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 8.2.1 Single Pointings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 8.2.2 Rectangular Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 8.2.3 Offset Versus Absolute Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 9 The Visual Spectral Editor 65 9.1 Overview of the Graphical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 9.2 Viewing a Spectral Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 9.2.1 Science Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 9.2.2 Scheduling Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 A Create an External Ephemeris 69 A.1 NASA resources for HORIZONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 A.2 Instructions and Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 A.3 Example Ephemeris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 B Acronym List 75 3 This page was intentionally left almost blank 4 Chapter 1 Introduction The OT User Manual describes the ALMA Observing Tool (OT) that is used to prepare observing proposals (Phase 1) and to schedule approved observations (Phase 2) for the Atacama Large Millimeter/submillimeter Array (ALMA). The OT is a Java-based application consisting of a set of user interfaces that are needed to prepare an ALMA observing project. This consists of a valid observing proposal and/or an observing program containing one or more Scheduling Blocks that are executed at the telescope. 1.1 How to Use this Manual Firstly, it is important to explain what this manual is not. • It is not a step-by-step guide to creating an ALMA proposal and/or observing program. Especially for inexperiencedusers,suchastep-by-stepguidetoproposalcreationisavailableintheformoftheOTQuick Start Guide, which can be obtained either through the OT’s internal help system or through the ALMA SciencePortal. ObservingprogramsarenotintendedtobecreatedbynormalusersandthereforeaPhase-2 counterpart to this does not exist. • This manual is also not designed to describe everything that can be possibly be done with the OT, and in particular does not give an explanation of what each and every entry field in the OT does. If this is desired, then the OT Reference Manual should be consulted. • Detailed technical information about ALMA is also not provided although, particularly with regard to the tuning and correlator setups, the basics are covered. The ALMA Technical Handbook is highly recom- mended for those users who want to know, well, everything. • Finally,thismanualdoesnotcoveradvancedusebytheALMAcommissioningteamsperforming“Extension andOptimizationofCapabilities” (EOC)inChile. StartingtheOTinitsCSVALMAmodemakesavailable more capabilities than are provided to normal users so that these can be tested. There are also fewer validation checks. Once a mode has been tested by EOC it is then usually transfered to the main OT for use by PIs. Instead, this manual attempts to give an overview of what is possible with the OT by a typical science user, without going in to the kinds of detail covered in the resources mentioned above. Therefore, Phase-1 proposals are described in terms of their main components, their purpose and what kind of information should be entered. Wheredetailisgiven,itgenerallycoversaspectsoftheOTthatarenotobvious. Alistofacronyms(AppendixB) may prove useful. UserswhoarecompletelyunfamiliarwiththeOTarerecommendedtoreadthefollowingchapters: Chapter2 provides information about how to install, configure and run the Observing Tool, Chapter 3 describes the main components of an observing proposal and program, and Chapter 4 provides a general overview of the OT. 5 In order to create a Phase-1 proposal, all the essential information is covered in Chapter 5 – this describes the process in some detail and should be read by all users. Complementary to this is Chapter 7 which describes various OT tools and Chapters 8 and 9 that give detailed information on how to use the visual spatial and spectral editors. Phase-2programsarecoveredinChapter6wherethisessentiallymeansSchedulingBlocks. Itisnotenvisaged that PIs will ever be involved with editing the contents of SBs, let alone create them manually, and this chapter therefore remains only or practical interest to observatory staff. 1.2 User Support Ineachofthethreepartnerregions,anALMARegionalCentre(ARC)hasbeenestablished. EachARCprovides scientific user support in the core areas of proposal preparation (Phase 1), observation program preparation (Phase 2) and data analysis to users in their respective communities. The ARCs will also host copies of the ALMA Archive and will deliver data packages to users. Hence, the ARCs are the ALMA interfaces to the user. More detailed information about the ARCs and how the interaction with the user communities is organised can be obtained from their Web sites. The following three URLs point to the European, North American, and East Asian ARC sites: Europe: http://www.eso.org/sci/facilities/alma North America: https://science.nrao.edu/facilities/alma East Asia: https://researchers.alma-telescope.jp/e/ea-arc/ Before and after the observations you will have regular interaction with your ARC. The degree of interaction will vary and depend on your experience and the complexity of the project undertaken. For simple projects, experienced users may only need to submit their Phase-1 and Phase-2 programs without any need for further supportandtheywillreceivetheirdatapackagefromtheARCs. Inexperiencedusersandmorecomplexprograms may require active ARC support during all phases of the observing program. IntheeventyouencounteraproblemorneedsupportwhenusingtheALMAObservingToolyoucancontact the ALMA User Support Service at your ALMA Regional Centre (ARC) or use the ALMA Helpdesk. All of these can be reached via the ALMA Science Portal: http://www.almascience.org 1.3 Release Information This version of the manual is intended to be used with the OT that will be used to submit normal (non-DDT) proposals for Cycle 9. 1.4 Credits and Acknowledgements The ALMA OT is a software product of the ALMA Observation Preparation Software Team and is developed on the basis of the ALMA Science Software Requirements (SSR) and the ALMA High Level Analysis (HLA) documents, produced by the respective groups. The OT software group acknowledges the valuable inputs of these groups during the development phases of the OT. Testers from the external community are also thanked for their valiant efforts over the years. 6 Chapter 2 Install and Run the Observing Tool The ALMA OT is written in Java and can be installed in two different ways, using an installer and with a traditional tarball distribution. We recommend using the former as it’s simpler and also gives the user the optiontoincreasetheamountofheapspace(memory)madeavailabletotheOT–thiscanbeveryhelpfulwhen processing large proposals. If problems are encountered during installation and/or operation of the OT, users are recommended to examine the Science Portal, especially the OT Troubleshooting and Known Issues pages, for solutions. The Helpdesk1 may also contain useful information via its Knowledgebase system. If a solution to a problem cannot be found, a user should then open a Helpdesk ticket. 2.1 System Requirements 2.1.1 Java There have been great changes to Java in the last few years. Java 11 is the current “long term support” version and ALMA now uses this when building its Java-based software tools. Unfortunately, Java 11 doesn’t include the previously standard installation method (Web Start) and so this is no longer available. A new installer based on InstallAnywhere has been developed that should continue to offer a more user-friendly and automatic installation to that offered by the “tarball” approach. As the new installer contains a Java distribution, it is no longer be necessary to have Java 11 installed on your machine. However, a tarball download without Java will also be made available and, if so, the situation is unchanged from before i.e. a fully functioning Java Runtime Environment (JRE) must be installed and only Java 11 will work correctly. IfaversionofJavahasbeeninstalledbytheuser,itsversionnumbercanbecheckedbytypingjava -version on the command line, the output of which should look something like this: java version "1.8.0_271" Java(TM) SE Runtime Environment (build 1.8.0_271-b09) Java HotSpot(TM) 64-Bit Server VM (build 25.271-b09, mixed mode) The number that follows the underscore refers to the update of the Java version that has been installed. When reporting a problem with the OT, the full version number including the update should be reported. It may be possible to work with two different user-installed versions of Java (i.e. 8 and 11) and switching between these. 1https://help.almascience.org/ 7 2.1.2 Supported Platforms The OT should run on any machine so long as a version of Java is available. This is because the JRE includes a Java Virtual Machine (JVM) which actually executes the platform-dependent OT code. Regular testing of the OT has found that it works using all common Linux distributions, Mac OS X and Windows. When reporting bugs, the platform on which the OT is installed should be included. 2.1.3 Disk Space and Memory The basic OT release (tarball) takes up about 100 MB of disk space, but is significantly larger (∼200 MB) if Java is included. If the new installer is downloaded the required space is closer to 300 MB. The default memory allocation for the OT is 4 GB, but this can be changed using the OT Installer. This large amount of memory means that only 64-bit versions of Java can be used with the OT. 2.1.4 Mac Issues Macs contain a security application called “Gatekeeper” that can cause problems when installing the OT, espe- cially on machines running Mac OS versions more recent than and including Catalina. Here we include some information that might prove helpful, when working with both the installer and the tarball. For example, starting the OT Installer will probably bring up a dialogue box saying that the application cannot be opened due to it or Java being from an unidentified developer. In order to overcome this one must open the “Security & Privacy” section of “System Preferences” and enable the installer there (“Allow Anyway”). This might need to be done even if the dialogue box does not mention the reason for the failure to run the installer. It is also probably necessary that the settings allow applications to run from “identified developers”. More information can be found at the following url: https://support.apple.com/en-us/HT202491 2.2 Using the OT Installer With the demise of Web Start, a replacement has been developed in the form of a multi-platform installer built using InstallAnywhere. This type of install method will be familiar to most users – the install package is downloaded and when opened takes the user through a multi-step process which results in the creation of an executable file with which the OT can be started. 2.2.1 Mac Installation TheOTInstallerforMacOSisavailableasaziparchivewhichismostconvenientlyextractedbydouble-clicking on the file in a Finder window – one of these can be opened from the directory where the archive is located by typing open . on the command line. The actual installer is called “almaot” (a command line ls will show that thisisadirectorycalled“almaot.app”)andcanalsobeopenedbydouble-clicking. Notepotentialproblemsgiven in Section 2.1.4. Oncetheinstallerhasbeenstarteditwillbringupasuccessionofdialogueboxeswhichwillguideyouthrough the very simple install procedure – see Figure 2.1. In most cases one will just need to click “Next” several times. ThedefaultinstalllocationistheApplicationsdirectorywithashortcutcreatedontheDesktop–double-clicking this will start the OT. 2.2.2 Linux Installation ForLinuxdistributions, theinstallprocedureisverysimilartothatdescribedaboveforMacs, butthedownload has the extension “.bin” instead of “.app”. This is an executable file (you may have to change the permissions to 8