Part I: Introduction to Reducing the HST Data

1.1 Archive Overview

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The HDA contains all HST observations ever made. It also contains a database that catalogs and describes these observations. The archive provides On-the-Fly Reprocessing (OTFR) of HST data for the following instruments: ACS, WFPC2, NICMOS, and STIS. The OTFR system reconstructs FITS data files from original telemetry and calibrates data at the time that a user's request for the data is processed. Through this system, users obtain data calibrated with up-to-date reference files, parameters, and software.

There are currently two ways to search and retrieve data from the HDA. The first is a program called StarView, which acts as an interface to the HDA. StarView currently runs as Java-based, stand-alone application that can be downloaded from the web site http://starview.stsci.edu/html/. Previous versions of StarView, such as XStarView, are no longer available. The second search and retrieval method is through the MAST web site, http://archive.stsci.edu. StarView is the more powerful of the two methods, and, in particular, allows an examination of the calibration files applied to a given data file. StarView also provides an interface to the Visual Target Tuner (VTT) in the Astronomer's Proposal Tools (APT) suite of programs. The VTT interface can display archive observations on a Digital Sky Survey (DSS) image alongside planned observations. StarView is thus recommended for observation planning, duplication checking, calibration file review, investigation of On-The-Fly Reprocessing flags and proprietary status. It is also recommended for those needing to retrieve large numbers of datasets, and those needing to examine calibration files. The MAST web site interface to the HDA has the same basic capabilities as StarView, and may be preferable for those requiring simple retrievals of datasets. Both StarView and the MAST web site allow cross-qualified searches of the other MAST mission archives for all HDA searches. They also offer simple preview of HST datasets when available, as well as links to references citing a given dataset using the Astrophysics Data System (ADS). In later sections, StarView and the MAST web site are discussed in more detail.

1.1.1 Archive Registration

The simplest way to register and retrieve HST data is to complete the form on the Web page at: http://archive.stsci.edu/registration.html. If problems occur, registration requests may also be sent to the HDA hotseat, at archive@stsci.edu.

The PI of each HST proposal must request access to their proprietary data for themselves, and for anyone else whom the PI wants to have access to it. PI retrieval permission is not granted automatically, for security reasons. PIs wishing to allow access to their proprietary data should make that request to archive@stsci.edu.

When registration is granted, your account will be activated automatically, and you will receive your username and password via e-mail.

1.1.2 Archive Documentation and Help

The MAST web site provides a wealth of useful information, including an online version of the HST Archive Manual available at http://archive.stsci.edu/hst/manual. Investigators expecting to work regularly with HST and other datasets supported by MAST should also subscribe to the MAST electronic newsletter by sending an e-mail to archive_news-request@stsci.edu and putting the single word subscribe in the body of the message. Questions about the HDA can be directed to archive@stsci.edu, or by phone to (410) 338-4547.

	Space Telescope Science Institute http://www.stsci.edu Voice: (410) 338-1082 help@stsci.edu