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Retrieval Options

Once observations of interest are found, registered and anonymous users can retrieve the data. We describe here the various retrieval options for HST data and explain the various terms involved, which you will encounter on the retrieval page.

Retrieving Public Data Anonymously
You can retrieve public data using the username "anonymous" and your email address as your password .

Archive Username
Your archive username. This is the username you were given when you registered for an archive account. If you don't have an archive account, you can register on-line or use the anonymous method for public data. If you register, you should receive your archive username and password via email in a few minutes.

Archive Password
Your archive password. This is the password that was given to you when you registered for your archive account. (See Archive Username, above.)

Delivery Options
How you want the data sent to you. You may chose either an electronic delivery option or a hard-media delivery option.

FTP: FTP the data to the destination shown
The data will be FTPed to the given destination.

SFTP: sftp the data to the destination shown
The data will be FTPed to the given destination using OpenSSH v2.

STAGE: Put the data onto the Archive staging disk.
The data will be written to the Archive staging disk. After the data are staged, you can download them via FTP from Proprietary as well as non-proprietary data may be staged. Proprietary data, or any data you retrieve under your archive username and password, will require you to login to the FTP server with that username and password to download your data. Data retrieved anonymously may be downloaded either as anonymous or using your archive username and password. If the data is non-anonymous, you may delete your data when you are done. Anonymously retrieved data may not be deleted by users.

DVD: Send the data to me on DVD.
The data will be written to a DVD and delivered to the mailing address you gave when you registered.

CD: Send the data to me on CD-R.
The data will be written to a CD and delivered to the mailing address you gave when you registered.

DISK or Hard Drive: Send the data to me on a Hard Drive
You may request data to be delivered on an external hard drive if you anticipate many GB of data retrieval. Currently the hard drive must be returned to STScI after the data are read onto your local drive. We have a limited number of drives for use and you MUST contact the Archive Hotseat (410-338-4547 or to coordinate your requests and use of the hard-drive option.

Verify Your Mailing Address
If you select one of the hard media options (DVD or CD-R), we will show you your current address and ask you to verify that it is correct. If you need to make changes to your mailing address, simply make the changes in the form before clicking the Send retrieval request to ST-DADS button. Your request will not be sent until you click on this button.

You may also update your address using the account maintenance form

The mailing address we ask you to verify is stored in our database of registered users. This address will be used for all of your hard-media requests. You currently cannot have two hard-media requests in process at the same time with two different mailing addresses. All hard-media requests will be shipped to the address given in the registered users database.

Destination (if you selected FTP or SFTP)
This is where you would like the data sent. These fields are required if you select the FTP retrieval option. The data will be delivered to this destination via FTP.

The hostname of the destination.

The name of the directory to which the data will be written. Please make sure that this directory exists, is writeable, and has enough space. The retrieval will fail otherwise. (Unfortunately, for technical reasons, we can't reliably estimate the size of your retrieval until the files are read from the optical platters, so we can't tell you whether there is enough space there, but generally, retrievals are rarely more than a gigabyte in total size.)

The username to be used when FTPing the data.

The password for the destination username.

Invalid Password Characters
There are five characters which, if present in a password, will cause the retrieval to fail: (, ), *, ", and /.

Retrieval Security
All the information you enter in this form will be sent to ST ScI through an SSL (encrypted) web connection using a Verisign certificate. The password remains encrypted until it is needed to transfer the data to you. The password is not retained after the data are transferred.

If your local system disallows FTP access or sftp (OpenSSH v2), and you are requesting only public data, you can use the STAGE option. If you are requesting proprietary data, you may select a hard-media option (CD, DVD).

Science Files Requested
The type of science files (as opposed to reference files) that you would like.

On-The-Fly Reprocessing
ST ScI's On-the-fly Reprocessing (OTFR) system for WFPC2 and STIS was opened to external users in December of 1999. As of June 2000, ST ScI stopped archiving calibrated data for WFPC2 and STIS. In the first week of April 2001, we released the On The Fly Reprocessing System for STIS and WFPC2 data. On-the-fly Reprocessing for NICMOS data was implemented on Septmeber 26, 2001. ACS data uses the OTFR system.

Archived version of calibrated science data for non-OTFR instruments and OTFR data for OTFR instruments.

Raw science data. For OTFR, the "raw" FITS files are generated from telemetry.

Data Quality
Reports describing science data quality.

Observation Log Files
Jitter and pointing data files.

Waivered Fits
Now that most WFPC2 data have been reprocessed, MAST has discontinued on-the-fly reprocessing and supplies calibrated images directly from the static archive. By default, these files are delivered in multi-extension FITS (MEF) format. If you would prefer to receive the wFITS format previously used for WFPC2 data, check the box below. For details, see the WFPC2 Reprocessing page

Reference Files
Files used for calibration. You may select either the files that were used when the data was originally calibrated just before archiving, or the calibration files that should be used if you plan to recalibrate the data for non-OTFR instruments. Only the best files are available for data from OTFR instruments.

Used Reference Files
Files used for original calibration.

Best Reference Files
Files to use for recalibration.

File Extensions Requested

Entering specific file extensions
Enter the specific three-letter file extension if it is not listed in the scrolling listbox. Remember that science data is archived in FITS format (not GEIS), so for example, the .c0h and .c0d files will be combined into a single extension: c0f.

For common questions about retrievals see our FAQ page.