SAS watchout


SAS watchout

In this page some issues concerning SAS and XMM-Newton data analysis are reported, along with recommended workarounds and/or solutions, and useful tricks and tips.

Many of the items below are extracted from the HelpDesk questions database, and frequently updated.
Users are invited to search this database, especially the SAS related folders, before contacting the XMM-Newton HelpDesk.

In addition, users should also check release notes of latest SAS patches, available on the SAS News web page, as a new patch might have been released already fixing the encountered problem.

If you encounter a new issue in analyzing XMM-Newton data with the SAS software, please try to give as much information as needed to reproduce your problem, including the following details:

  • Output of the sasversion command,
  • Observation identifier,
  • Information about the CCF in use.

Current SAS Version related issues

SAS 21.0.0

  • I am getting the error (constituent) while running epchain. What can I do? -- Answer
  • I am having problems running SAS v21.0 on Ubuntu 18.04 and CentOS 7.3. What can I do? -- Answer

SAS 20.0.0

  • None

SAS 19.1.0

  • Whenever I run the task cheese, which is one of the ESAS tasks, I get the following error message:
      /usr/bin/env: `perl/r`: No such file or directory.
    However, I did install properly Perl following all the indications in the requirements page.
    How to fix this problem? -- Answer
  • After installing SAS 19.1.0 for macOS (sas_19.1.0-macOS-10.15.7.tgz) on macOS Catalina (v10.15.7) or on macOS BigSur (V11.2.3), running either on Intel or on the new Apple processor M1, with SIP enabled, I got an error message similar to the following:
      dyld: Symbol not found: ___emutls_get_address
        Referenced from:
        Expected in: /usr/lib/libSystem.B.dylib

    How to fix this problem? -- Answer

SAS 19.0.0

  • Mosaiced images displayed with wrong coordinates in DS9 v8.1 and later.

    How to fix this problem? -- Answer

SAS 18.0.0

  • During the installation of Python performed in the general installation of SAS 18, an error message similar to the following is obtained (the example is taken from the installation of SAS 18 on a macOS machine):
    Checking for the RELEASE file: OK
    Checking we are in the top directory: OK
    Checking for presence of : OK
    Checking whether perl is available or not ...
    /usr/bin/perl is available. It will be used in all SAS perl tasks.
    Checking whether a proper SAS Python environment is available ..
    * 'conda' command was not found. 'conda' is not installed or not found in your system.
    * 'Miniconda' package and environment manager will be installed under the SAS installation directory.
    * This may take a while depending on your internet connection. Please be patient ...
    Miniconda installation file is ready:
    Starting Miniconda installation ...
    Miniconda was NOT installed under
    /user_selected_directory/xmmsas_20190531_1155/miniconda3. Exiting.
    How to fix this problem? -- Answer
  • When installing the proper SAS build either on Linux or macOS systems, a problem arises during the part that deals with the installation of Python modules. This problem is easily identified because the installation procedure starts looping with messages of the form:
    Downloading Python modules needed for SAS from Conda repositories . . .
            !!! Some needed Python pkgs are missing unedr the environment: sas_18.0.0. Exiting !!!
            Ready to install the correct Python environment for SAS \u2026
            (Python env sas_18.0.0 will be removed and re-installed for the correct one)
    Package plan for package removal in environment /xmmsas_20190531_1155/miniconda3/envs/sas_18.0.0:
    The following packages will be REMOVED:
        asn1crypto:         0.24.0-py36_0
        astropy:            2.0.1-np113py36_0
        atomicwrites:       1.3.0-py36_1
        attrs:              19.1.0-py36_1
        blas:               1.0-mkl
        ca-certificates:    2019.8.28-0
        certifi:            2019.9.11-py36_0
        cffi:               1.12.3-py36hb5b8e2f_0
        chardet:            3.0.4-py36_1003
        cryptography:       2.3.1-py36hdbc3d79_0
        cycler:             0.10.0-py36hfc81398_0
        freetype:           2.5.5-2
    (list truncated for clarity)
    How to fix this problem? -- Answer

SAS 17.0.0

  • When I connect to a Mac machine via ssh and run the xmmextractor GUI, I get the following error message:
      xmac01:Work sastest$ xmmextractorGUI
      _RegisterApplication(), FAILED TO establish the default connection to the WindowServer, _CGSDefaultConnection() is NULL.
      PasteBoard: Error creating pasteboard: [-4960]
      PasteBoard: Error creating pasteboard: [-4960]
      Segmentation fault: 11

    How can I fix this problem? -- Answer

SAS 16.0.0

  • After having patched the original SAS 16.0 version, trying to run the Perl task epchain, produces the error message
      epchain: Command not found
    while any other SAS task is found.
    How can I fix the problem? -- Answer
  • After installing SAS 16.0.0 on macOS Sierra (Mac OS X 10.12*), running any SAS task, e.g. epproc, produces the error message
      dyld: Library not loaded...
    How can I fix the problem? -- Answer
  • Running xmmextractor on Mac OS X 10.11.6 El Capitan, I get the following error message:
    Can't load '$SAS_DIR/lib/perl5/darwin-2level/auto/XML/LibXML/LibXML.bundle' for module XML::LibXML: dlopen($SAS_DIR/lib/perl5/darwin-2level/auto/XML/LibXML/LibXML.bundle, 1): Library not loaded: /opt/local/lib/libiconv.2.dylib
      Referenced from: $SAS_DIR/lib/perl5/darwin-2level/auto/XML/LibXML/LibXML.bundle
      Reason: Incompatible library version: LibXML.bundle requires version 8.0.0 or later,
      but libiconv.2.dylib provides version 7.0.0 at /Users/user/perl5/perlbrew/perls/perl-5.22.3/lib/5.22.3/darwin-2level/ line 197.
      at $SAS_DIR/lib/perl5/darwin-2level/XML/ line 156.
      BEGIN failed--compilation aborted at $SAS_DIR/lib/perl5/darwin-2level/XML/ line 156.
      Compilation failed in require at $SAS_DIR/lib/perl5/ line 5.
      BEGIN failed--compilation aborted at $SAS_DIR/lib/perl5/ line 5.
      Compilation failed in require at $SAS_DIR/bin/xmmextractor line 206.

    How can I fix this problem? -- Answer
  • After the installation of SAS 16.0.0 on MacOS X Yosemite or El Capitan, SAS initialisation produces the following error message:
    dyld: Symbol not found: __cg_png_create_info_struct
      Referenced from: /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
      Expected in: $SAS_DIR/libextra/libPng.dylib
      in /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
    Trace/BPT trap: 5

    How can I fix this problem? -- Answer

SAS 15.0.1

  • I cannot run SAS on macOS Sierra. What can I do? -- Answer
  • My observation has been made in EPIC multi-pointing mode, how can I process it correctly ? -- Answer

SAS 15.0.0

  • Can I use a box region to extract EPIC-pn Timing or Burst mode spectra? -- Answer
  • I am running the SAS 15.0.0 on a Linux RHEL 6.X machine and xmmextractor is crashing.
    How can I fix this problem? -- Answer
  • When the task emosaic_prep is ran, it gives the following error:
    Cannot exec "preqgti": No such file or directory at...
    How to fix this problem? -- Answer
  • Why do certain tasks end with a fatal error including: UnknownAlgoId? -- Answer
  • dyld: Library not loaded... error with SAS installed on Mac OS X El Capitan -- Answer


Evergreen tips and tricks

  • Caution when applying the updated RGS-to-pn "Rectification Factors" -- Details
  • How can I correct OM Grism Spectra for Time Sensitivity Degradation? -- Answer
  • Caution when analysing EPIC Timing Mode spectra extracted from very narrow regions -- Answer
  • Caution when analysing EPIC spectra extracted from annular source regions -- Answer
  • Is the RGS-pn rectification correction valid for data processed with SAS 14? -- Answer
  • Why do I have to correct EPIC-pn Timing Mode exposures for X-ray Loading (only necessary for observations performed until 23 May 2012)? -- Answer
  • Should I use evselect or epiclcorr for obtaining EPIC light curves? -- Answer
  • These long parameter names are really annoying ... -- Answer
  • How do I compare two Calibration Index Files? -- Answer
  • Can I generate EPIC response matrices with all types of spectral binning? -- Answer
  • Where can I find canned EPIC response matrices? -- Answer
  • Can I perform the barycentric correction on OM data in Fast Mode? -- Answer
  • How can I convert from OM count rates to fluxes? An update -- Answer
  • Dealing with MOS1 data in Timing Mode: I heard that one column in MOS1 Timing Mode is affected by "high offset", can I still analyze the data? -- Answer


  • Why does it take so long to produce an ODF? -- Answer

PPS products

  • Why do I get problems ingesting RGS (pipeline) spectra into XSPEC V12.x and how can I solve this? -- Answers
  • How do I know which CCF were used to reduce my event list? -- Answer
  • I do not find EPIC (or RGS or OM) processed data in my PPS distribution. Did something go wrong with the pipeline processing? -- Answer


Previous SAS Version related issues

SAS 14.0.0

  • Why do certain tasks end with a fatal error: Unsupported AlgoId? -- Answer
  • Why does phasecalc not give me the correct phase reference epoch? -- Answer
  • The sourcing of the setsas.csh script to initialise SAS, produces the following error:
    SAS_PREV_LD_LIBRARY_PATH: Undefined variable. How to fix this problem? -- Answer
  • In Mac OS X, the execution of some tasks, e.g. epproc, omsource, etc, produces the error:
    dyld: Library not loaded: /sasbuild/local/xmac01/libpng_1.2.51/lib/libpng12.0.dylib
    Referenced from: /Users/user/SAS/xmmsas_20141104_1833/lib/libssc.4.28.dylib
    Reason: image not found
    Trace/BPT trap
    How to fix this problem? -- Answer
  • When the task emosaic_prep is run, it gives the following error:
    Cannot exec "preqgti": No such file or directory at.... How to fix this problem? -- Answer
  • Why epproc/epchain ends with a fatal error: Unsupported ALGOID? -- Answer

SAS 13.5.0

  • Are the recent CCFs compatible with SAS v13.5 ? -- Answer
  • What to do if emosaic_prep doesn't split the mosaic data properly? -- Answer
  • How can OM Fast mode data be processed measuring the background from associated Image mode data? -- Answer
  • Why are there library conflicts when running Heasoft tools? -- Answer
  • Why are ESAS routines within SAS needing special calibration files? -- Answer

SAS 13.0.3

  • Why did the names of the RGS extraction regions change with SAS 13.0? Answer
  • Missing libpng12.0.dylib when running SAS tasks on MacOSX 10.8.5 (Mountain Lion), 10.7.4 (Lion) and 10.6.8 ("Snow Leopard") 64-bit? -- Answer

Issues related to older SAS versions can be found on the SAS watchout archive page.