1. Introduction

1. Introduction

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a telescope with an effective diameter of 2.5 meters, carried aboard a Boeing 747-SP aircraft. It is the successor to the smaller Kuiper Airborne Observatory, which was operated by NASA from 1974 to 1996. The observing altitudes for SOFIA are between 37,000 and 45,000 feet, above 99% of the water vapor in the Earth's atmosphere. The telescope was designed to allow imaging and spectroscopic observations from 0.3 to 1600 μm, with specific capabilities dependent on an evolving science instrument suite, making it one of the premier facilities for astronomical observations at infrared and sub-millimeter wavelengths. The present instrument suite provides coverage from 0.3 - 240 μm with additional capabilities currently in development.

SOFIA is a joint project of NASA and the Deutsches Zentrum für Luft und Raumfahrt (DLR). The SOFIA Science Center (SSC), responsible for overseeing the scientific aspects of the mission, is located at the NASA Ames Research Center in Moffett Field, CA. Flight operations are conducted out of the NASA Armstrong Flight Research Center (AFRC) in Palmdale, CA. The Science Mission Operations are jointly managed by the Universities Space Research Association (USRA) for NASA and by the Deutsches SOFIA Institut (DSI), in Stuttgart, for DLR. Aircraft operations are managed by NASA AFRC.

Most of the observing time on SOFIA is open to the international astronomical community via General Investigator (GI) proposal calls, which are issued on a yearly basis. The first of these proposal calls was for "Early Science,'" for which observations were obtained in a series of flights from May - July, September, and November 2011. The first open call for proposals, Cycle 1, covered the period from late 2012 to the end of 2013. The current proposal call is for Cycle 5 observations, which will take place between 1 February, 2017 and 31 January, 2018.

1.1 Intended Readership

This document, the "SOFIA Observer's Handbook for Cycle 5" (hereafter the Observer's Handbook), provides information about SOFIA operations and the instruments that will be available for observations during Cycle 5, nominally scheduled for 1 February, 2017 - 31 January, 2018. The Observer's Handbook is the primary technical reference for astronomers who wish to submit a proposal for SOFIA Cycle 5. The information contained herein, and in documents and websites explicitly referred to, should be sufficient to allow proposers to plan viable SOFIA observations.

1.2 Updates to the Observer's Handbook

This version of the handbook is applicable to for Cycle 5. Between the time of writing and the start of Cycle 5 observations, the analysis of data obtained as part of ongoing Instrument Commissioning work for HAWC+ are likely to provide more empirical information regarding instrument performance. The Observer's Handbook will be updated as necessary and the list of changes will be included at the beginning of the document. Critical updates will also be published on the Cycle 5 web page. Any information that supersedes what is given in this document will be explicitly indicated.

1.3 Other Documents and Resources

The following additional documents are available on the SOFIA Information for Researchers web pages.

  • The "SOFIA Cycle 5 Call for Proposals" describes how to prepare and submit proposals. It includes details on how proposals will be evaluated. It formally establishes the policies for all matters concerned with the rules governing SOFIA Cycle 5 for guest investigators.
  • The "FORCAST Observation Modes" document provides an explanation of the basic FORCAST observing modes for imaging observations. It is referred to explicitly in Section 7 below.
  • The "Guide to Observation Planning with GREAT" is a tutorial for estimating exposure times for observations using GREAT. It is referred to explicitly in Section 9 below.
  • The HIPO Throughput/Sensitivity Spreadsheet provides tools to estimate the signal-to-noise for HIPO observations.
  • The Science Instrument Suite web pages provide a brief overview of the suite of instruments that will be available on SOFIA once it reaches full operational capability.
  • "The Science Vision for the Stratospheric Observatory for Infrared Astronomy" presents many compelling science questions that SOFIA is uniquely positioned to address. The complementarity among several astronomical facilities (current and future, particularly in the IR/mm wavelength regime) are discussed where relevant. Please note, that any information regarding the performance of the telescope and instruments contained within the "Science Vision" is superseded by this document and the SOFIA web sites.