Quick Start Guide

This section is intended to provide a dialogue and inputs which will give good results for beginning users. Please let us know how it goes, and ask any questions you have. Send feedback and questions to help@stsci.edu.

Please note that AURA/STScI is not responsible for any damages resulting from use of this software.

As you are working through this guide, you can copy and paste text from this file into your terminal window, if that helps you work faster. Or you may want to copy blocks of text into a text file, to create your own customized dialog and commands.

If you don’t have it already, you will need to install the AstroConda distribution with legacy IRAF support available at http://astroconda.readthedocs.io.

After AstroConda is installed, open a new session (open a new Bash terminal and type source activate astroconda).

To install the stis_cti package and dependencies, run:

pip install stis_cti

Or, to upgrade from a previous version, run:

pip install --upgrade --no-deps stis_cti
pip install stis_cti
pip install --upgrade --no-deps refstis
pip install refstis

After that, open a brand new AstroConda session (see above), and continue there. Create a working directory where the data will reside, and also create the necessary sub-directories. For example, our disk here is called /Users, and the account is biretta, and we might use the proposal number 13542, so our working directory was /Users/biretta/13542.

source activate astroconda
mkdir /Users/biretta/13542
cd    /Users/biretta/13542
mkdir darks
mkdir ref
mkdir science

Place the raw science data in the science directory. This will include the files you got from the archive: *_raw.fits, *_epc.fits, *_spt.fits, *_asn.fits, *_wav.fits

Note that the presense of non-CTI-corrected products from the archive (e.g. *_flt.fits) will not interfere with the processing.

We will assume you want the script to automatically download the reference files from the HST archive. We do an initial run of the script from the science directory:

stis_cti --crds_update

It is expected the script will run for a minute, and then give an error message, along with a URL to get the dark frames that are missing, and then stop:

ERROR:  These FLT component darks are missing from ../darks/:
Please download the missing darks (calibrated FLTs) via this link:


Next we need to get the missing dark frames. Copy the entire URL which the script generated, and paste it into a web browser (e.g. on a Mac highlight the URL with the cursor, and hit command-c, move the cursor to the web browser URL bar, and hit command-v). Then hit return. This will generate an HST archive request for the missing dark files. Then do this on the archive web page:

Click [Mark all]

Click [Submit marked data for retrieval from STSDAS]

This will bring up a new page. Fill out your HST archive credentials, and the computer and directory where you want the files to be sent:

Check [sftp the data]

myserver.mydomain.edu (put your computer name here instead)

/Users/biretta/13542/darks  (use the darks directory that we created earlier)

biretta (put your computer account name)

(put your computer password)

Alternatively, you may stage and retrieve files from the archive’s ftp server.

File options: check Calibrated (it will probably checked already by default)

Click [Send retrieval request to ST-DADS]

Then wait for the dark frames to be delivered by the HST archive.... After you receive an email from archive.stsci.edu that the request has completed successfully, put the darks in the darks/ directory and run stis_cti again. This time it should run to completion. On a typical Mac laptop, it might take an hour to run. Make sure you are in the science directory still, and then:

stis_cti --crds_update

When you get the message that looks like:

Completion time:                2015-06-12 19:51:29.862291
Run time:                       0:23:05.068940
stis_cti.py complete!

...it is done running. You should find the output files in the science/ directory with names like *_cte.fits, *_flc.fits, *_crc.fits, etc.


For recent STIS observations (new data taken in last 30 to 60 days) optimal dark reference files will not yet be available. This will affect the selection of data being used to generate the CTI-corrected super-darks. To get the most accurate calibration, please re-reduce your data after the pipeline’s new super-biases and super-darks have been delivered by deleting the relevant old CTI-corrected super-darks in the ref/ directory and running stis_cti with the --clean and --crds_update options specified. You may need to download additional component darks from MAST.

To receive updates when STIS reference files are delivered to CRDS, go to https://maillist.stsci.edu and subscribe to the stis_reffiles_upd mailing list.

You can also check the status of super-dark and super-bias files by going to https://hst-crds.stsci.edu and clicking on STIS–>darkfile and STIS–>biasfile. Sort by USEAFTER to see if the week corresponding to your science data has been delivered yet.

Good luck! Let us know if you encounter problems, or need any assistance at help@stsci.edu.