Astronomical Image Processing System
Solaris binary support is ending
The support for the Solaris operating system in Socorro will be
terminated at some, yet to be determined, time in the next 6
months or so. The computer that provided AIPS compilations has
died and been replaced with an older, and very slow, computer.
When this computer dies, or when support is formally withdrawn,
we will no longer be able to offer a binary installation for
DEC Solaris computers. If you have this sort of computer, you
may still take AIPS in text form and compile it locally. The
code was corrected a while back to survive modern Fortran
compilers and the Solaris scripts for compiling AIPS have been
used for a great many years.
Warning about modern Linux operating systems
Good news: I tried compiling the
LNX64 binary installation with the latest Intel compiler
(18.0.0, 20170811). Everything ran well on NRAO computers,
but the installation failed in Leiden without even getting to
the Nan issue. The binary installation has been rebuilt,
therefore, with gcc and gfortran (version 6.4). That
installation works normally in Leiden. The following is left,
for now, to document the issue.
Computers that ran AIPS perfectly well with the binary
installation have suddenly run into mysterious issues after an
operating system upgrade. These issues are discussed below.
Both Leiden and Jive report that the issues go away if they
compile from source using gcc and gfortran. I (Eric) use gcc
version 6.3 on my machine and some of the gcc versions 5.x also
worked fine (latest here was 5.4). The problem is being
One of our users had his computer "upgraded" to the Fedora OS
version 25. Instantly, multiple AIPS tasks started producing
NaNs scattered amongst the correct values. This happened in
multiple versions of AIPS using binaries downloaded from NRAO
over a long span of time. The results do depend on the inputs,
but if the inputs are not changed, the results even from
multiple versions of AIPS remain the same. We will attempt to
investigate this further, but, for the moment, we recommend
strongly that you do not install this version of Fedora. Note
that AIPS worked fine under previous versions, 24 and less.
And the contagion is spredding: A second site has now
reported the same problems on both Fedora 25 and 26. The
RedHat 7 system in Leiden has suddenly developed the same
issues after having worked well for quite some time. And now
Jive has reported NaN issues with Arch Linux 4.12.12-1-ARCH
kkernel 4.12.12) and Debian 9. Yet another site has reported
this failure with Scientific Linux 7.4, while SL6 still works
Further study in Leiden has found that computers with
varied but rather modern hardware fail under both Fedora and
RedHat 7, while somewhat older computers run AIPS perfectly
well under both. A local compilation with gfortran 6.? was
done on one of the failing Fedora machines and the resulting
AIPS worked properly. I am concerned that the Intel compiler
we use for 64-bit Linux is too old; it dates from January
2009. We will be looking into something more modern.
AIPS has now been tested with a Fedora 25 virtual machine
and the tasks that failed in Leiden worked fine on the same
data when run in Socorro. Perhaps the only issue was
something wrong with some installations of Fedora 25
including the one in Leiden.
Another user has reported problems with IMAGR under Ubuntu
17.04 that went away when she reverted to Ubuntu 16.04 LTS.
NRAO has instituted a "helpdesk" system
similar to those at other astronomical institutions. AIPS will
participate in this effort which is intended to avoid having
problems fall between the cracks. The helpdesk is accessed via
that the help site will forward you to my.nrao to create a login
if you do not already have one and the my.nrao site will then
offer a tab to reach the helpdesk. The system for the AIPS
"department" will make use of the email@example.com list manager
system that we have used for years. Thus, unlike the rest of the
NRAO helpdesk, messages to the AIPS portion will be made public in
the daip archive. This archive is accessible via the web and is
well known to Google among other things. Please switch to the new
helpdesk to allow more systematic handling of your AIPS queries
and bug reports.
The development version 31DEC17 is
available, the previous development version 31DEC16 is frozen
(except for patches), and the old frozen version 31DEC15 will not
be available for installation much longer. (A MNJ on 31DEC15, if
it has not been run since September 30, 2015, might still be
useful.) The new cvs form of the Midnight Job has been very easy
to use and effective in keeping numerous sites up to date. In
2017, the MNJ will work sometimes on 31DEC16 if there has been a
released patch. The 31DEC17 and 31DEC16 releases are also
available as binary installations (and MNJs). The 31DEC16 MNJ no
longer requires cvs for binary installations, just rsync.
TeK and message server problems
Users have encountered problems getting
the TeK and message servers to work in binary installations.
These servers are programs which run in an xterm and that xterm
must come up with some knowledge of AIPS libraries. This requires
users to modify their login scripts (e.g. .cshrc file for c shell,
.bashrc file for bash). See
Linux compiler troubles
There appear to be problems with many of the versions of the
gcc/g77/gfortran compiler suites. GNU compiler versions 2.* and
3.* are now obsolete and the performance under g77 left much to be
desired. The 31DEC15 version of AIPS has received attention so
that it may be compiled under gfortran/gcc. Versions 4.4.7,
4.8.3, 4.9.2, and 5.1.0 have been tested and appear to work.
Versions 4.8 and 4.9 require changes to make the pseudo-AP fixed,
rather than dynamic, memory and to reduce the optimization of APCLN.
See the 31DEC17 release instructions for the
specifics of these changes. Versions
5.1.0 and 5.3.0 also appear to work and no longer have the
issues with the pseudo-AP.
Also, see the Users'
FAQ: answers to Frequently Asked Questions, the
AIPS Managers' FAQ:
answers to AIPS Managers (and installers) Frequent Questions; and our
page on who is in the AIPS
group. The AIPS Manager FAQ page is
especially helpful if you are having trouble getting the AIPS TV to
run properly or are encountering other general difficulties or wish to
configure new machines and disks in your AIPS environment.
is the new primary development version of AIPS. It is ready
for installation. The 6-month progress report on 31DEC17 is available as 31DEC17
AIPSLetter dated 30 June 2017 (PS, 902569 bytes).
It is also available gzipped,
(419491 bytes) and PDF,
is the previous development version of AIPS. It will be updated
regulary in December 2016 and occasionally in 2017 for patches.
It is available for installation. The final report on 31DEC15
is available as 31DEC16
AIPSLetter dated 31 December 2016 (PS, 957655 bytes).
It is also available gzipped,
(431102 bytes) and PDF,
(185628 bytes). The 6-month progress report on 31DEC16 is available as 31DEC16
AIPSLetter dated 30 June 2016 (PS, 907865 bytes).
It is also available gzipped,
(414726 bytes) and PDF,
is now obsolete. It will no longer be updated. It is available
for installation for a limited time. It is the final version
for which the Mac binaries will work on 32-bit computers. The
final report on 31DEC15 is available as 31DEC15
AIPSLetter dated 31 December 2015 (PS, 1001941 bytes).
It is also available gzipped,
(451446 bytes) and PDF,
(203207 bytes). The 6-month progress report on 31DEC15 is available as 31DEC15
AIPSLetter dated 30 June 2015 (PS, 914635 bytes).
It is also available gzipped,
(417682 bytes) and PDF,
will be available for installation only in 2015, after which it
will no longer be available. The last patch top 31DEC14 was
applied September 14, 2015. The final report on 31DEC14 is
available as 31DEC14
AIPSLetter dated 31 December 2014 (PS, 916765 bytes).
It is also available gzipped,
(425794 bytes) and PDF,
(160987 bytes). The 6-month progress report on 31DEC14 is
available as 31DEC14
AIPSLetter dated 30 June 2014 (PS, 765430 bytes).
It is also available gzipped,
(329413 bytes) and PDF,
- 31DEC06 and later releases contain a port to
the MacIntosh OS/X system running on Intel cpus. This includes
a full binary installation produced with Intel's compiler. An
AIPSMark of 150 was obtained on our iMac which will be used to
support this "new" architecture.
- Since the end of January 2009, Linux systems
running on 64-bit hardware with 64-bit operating systems have
the choice of using LNX64 rather than LINUX as their AIPS
architecture. The binary version for LNX64 is compiled with a
recent 64-bit Intel compiler and runs somewhat faster than the
LINUX version run on the same machines.
- Since September 1, 2005 the binary versions
for Linux are compiled with the Intel compiler version 9.0.
They are compiled and linked with options that make the load
modules rather large but allow them to run as well as possible
on the latest threaded Pentium IVs, older Pentium IVs, and on
general machines such as AMDs. Since November 30, 2004, binary
installations for MacIntosh OS/X (IBM xlf compiler), Solaris Ultra
(SUN compiler), and Linux (Intel 9.0) have been available. They
are on the 31DEC05 and later versions. At present, all versions
provide considerable advantages over systems done with free
- If you own a MacIntosh OS X computer, you
may now run AIPS. Get either of the above versions; all contain
the new MACPPC and MACINT ports. Note that the somewhat
expensive IBM and Intel compilers produce code which runs about
50% faster than the code produced by the GNU compiler. Binaries
compiled with the IBM and Intel compilers may be installed and
updated from our ftp site. That site is maintained by our Mac
computers in Socorro. Read also the special Mac installation instructions which are
supplements to the A Guide to the
Install Wizard instructions.
- When you get
the new install wizard; we have a good on-line guide that will help you
through it. Read it!
- The 15OCT99, 31DEC00, 31DEC01, 31DEC02, 31DEC03 31DEC04 31DEC05 31DEC06 31DEC07 31DEC08 31DEC09 31DEC10 31DEC11 31DEC12 31DEC13 31DEC14 releases of AIPS
are no longer available; the number of bug fixes and differences
between them and the
31DEC17 version have become too
great. The continued significant demand for a frozen, even if
obsolete, version was the main reason we decided to resume
TWO VLBI TUTORIALS
Two extensive tutorials on VLBI data reduction in AIPS have been
prepared, complete with data sets, introductory material about AIPS,
and detailed instructions. They are simple VLBA project including
spectral-line VLBA project plus astrometry. Users new to, or
rusty in, VLBI data reduction are encouraged to try these tutorials.
Appendix C and Chapter 9 of the AIPS CookBook
are also recommended.
There are sometimes considerations which users of older versions of
AIPS must take into account due to changes in the latest version. In
addition, there are sometimes bugs introduced into the latest version
which then get repaired in that version. Such matters may affect
those users who keep their AIPS up to date. These bugs often do not
get reported in the AIPSLetter since they were temporary but might be
of concern for diligent users. They are reported in
but those reports are sometimes fragmentary and confusing. We have
begun a new web page for problems of this
sort. It is hoped that we will keep it up to date.
You really should be getting 31DEC16 or 31DEC17 instead of patching an older version!
With previous releases, we did not change the
frozen release tar ball; user sites were required to download the text
files and do any compilations themselves. But, beginning with
31DEC04, we provide binary releases for which user sites are not
required to have compilers. Therefore, we have reversed our policy.
These patches have been applied to the official code of 31DEC16 and
may be downloaded using a 31DEC16 "Midnight Job". Any tarball taken
after the change date listed below will already have the patches
applied. Of course, you may still download and compile the files as
There are fifteen 31DEC16 patches.
There are three messy and nine normal 31DEC15 patch so far:
POSSM would not label correlation functions in
ATLOD would not open disk files properly.
CCRES did not honor blanked pixels
DFTPL did not use the correct frequencies when
BIF > 1. 2017-01-31
DBCON scaled uvw wrongly when combining data sets
of different frequencies. 2017-02-24
DFTPL did not address data correctly when the input
had more than one Stokes. 2017-02-28
BPASS did not normalize linear polarization
bandpasses correctly for normalization type 1.
- Automatic spectral index finding from the SU table had problems
when one or more IFs had no flux value.
UVMOD did not handle frequencies correctly with
SPIXR did not label the output images with the
frequency for which they were determined (1 GHz).
PCAL miscomputed the flux at 1 GHz for known
low-frequency sources. 2017-06-06
UVLSF copied tables twice to the output continuum
data set. 2017-06-30
SCIMG messed up the self-cal
step when the number of IFs was not the same as the number of
PCAL left a file open when an IF had no data in
spectral mode, causing failure on the next IF.
There were nineteen 31DEC14 patches:
GC tables used to allow 200 values of gain curve,
so restored this limit used by some correlators.
PBEAM scaled Stokes I data incorrectly when adding
right and left data files. 2016-01-12
DBCON re-instated flagged table rows.
DTSUM did not handle new internal format correctly.
PCAL typo caused errors in antennas used with the
new ANTENNA1, ANTENNA2 format. 2016-04-15
PCAL lost Faraday Rotation calibration when doing
SPECTRAL solutions. 2016-04-29
IMAGR found automatic boxes in only part of the
IMSIZE(2) < IMSIZE(1)
OOP editing had trouble with source number zero
sometimes found in tables. 2016-05-19
UVFIX used the actual observing frequency rather
than the one in the header to scale UVW.
OOSUB and other model subtraction/division could
get the scaling between frequency channels wrong.
UVLOD, FITLD did not find the subarray value
accurately enough. 2016-08-25
SPLIT did not write the correct header frequency
when averaging IFs with BIF greater than 1.
UVLOD did not test data
flagging correctly when writing and reading UV tables in
compressed format. 2016-08-31
There are twenty-four patches for 31DEC13.
DOFARS help and procedure contained
OUT2NAME et al. left over from when
used those adverbs. 2015-01-08
RMFIT failed to copy the
FQ table to
the output residual images. 2015-01-13
FTFLG messed up antenna numbers in the output
FG table whena single antena or baseline was used
VLBATECR had trouble around the endof the year
deciding what files needed to be downloaded.
convert to make the
html output files. Added tests and a control on
BPASS had an array and history writing code which
could not handle more than 32 antennas.
MORIF messed up bandpass and other spectral tables.
TYSMO did not clip bad values without any
median-window editing. 2015-02-11
BPASS did not understand that low-level VLB
routines expected left-handed antenna coordinates.
- UV data disk I/O had an issue if the full file fit into the
first of the two buffers and the disk file was exactly the right
START_AIPS, START_TVSERVERS needed a grammar change
to support Mac yosemite systems
- Basic calibration subroutines mis-computed the channel
wavelengths and did not always do dispersion correction
XAS needed a change to support Mac yosemite
systems and also to write a black character background
KRING help file adverb list did not match that of
IMAGR did not do the baseline-based time averaging
properly in the last baselines written to the work file
PCAL did not detect fully flagged channels when
using a source model and so died.
SETJY had bad formats capable of aborting the task
TVSAD hid the new model-fit
table when making a stars table. 2015-09-07
PCAL did not do mode
correctly, leaving files open and then quitting.
There are three large and nineteen more
normal 31DEC12 patches.
- Spectral index was not corrected when
BPASS even when there was only one calibration
LISTR failed to read source information when
printing "gains". 2014-01-14
DOOSRO run file had a typo in its first line
UVFND used the real part of channel-averaged data
for both real and imaginary parts 2014-02-07
DOBAND 2 and 4 modes had an initialization issue
DOOSRO pipeline procedure contained a POPS error
PCNTR had minor issues which
blocked display of true-color images.
PCCOR did not handle blanked values from the PC
table cable-cal measurements
FITLD had trouble finding the correct records for
DSKEW did bad things when the input image had a
non-zero value of rotation. 2014-03-17
CLCAL failed to re-reference the SN tables
when requested. 2014-03-19
SNP2D needed clarification of
BIF and to write reference channel phases as
well as delays. 2014-03-27
TIORD had a bad format.
RMFIT called the function
routine incorrectly numerous times, mostly with remarkably
benign results. 2014-04-02
PRTAB could abort when string data was very long.
LISTR did not show the correct scaling for angles
GAIN listing. 2014-04-11
SPFLG interpreted flagged
rows in the flag command table as a serious error in a couple
of places. 2014-05-29
DTSUM omitted the highest numbered antenna from
its matrix list if it did not have autocorrelation records.
CALIB in phase-only solutions could return
amplitude gains other than 1.0 when only 2 baselines occurred
in an interval. 2014-06-27
PCAL did not take data flagging into account when
averaging data over time. 2014-08-08
TYSMO did not apply flagging correctly except if
all flags applied to all Stokes. 2014-08-21
BPASS did not allocate quite enough dynamic memory
causing bad messages when it closed. 2014-09-12
SPFLG, TVFLG, FTFLG made a mess of the header in
memory when trying to load a fully flagged plane making many
operations other than a good TV load fail.
FITLD had trouble finding widely spaced records
- Bandpass calibration was not applied to enough channels to
support post-BP frequency smoothing 2013-01-16
- Tick increments were computed with an erroneous round-off
parameters leading some tick marks to be plotted at offset
POSSM had a number of minor irritating bugs.
FITLD turned off DIGICOR corrections if the array
name is not VLBA. 2013-02-05
FITLD after above correction failed if it could
not make a
CQ table. 2013-02-18
CL2HF aborted because of an internal name conflict
PRTAB aborted when writing large values with F
COMB did not do POLC correctly when using constant
noise values 2013-04-04
AFARS had an addressing bug causing it to try to
write too much 2013-04-05
FITLD could get the
EQUINOX wrong in
SU table with FITS-IDI input
COMB messed up scaling when combining two images
with one of them not
FITLD had a warning message with more arguments
than format items 2013-05-21
BPASS rounded times outward for each scan by too
IMAGR computed the actual average frequency
JMFIT could return negative
error bars when the object was negative
TRANS messed up reversing the order of axes
greater than one while swapping the same axis
PRTAB had formatting issues with large tables,
magic blanks 2013-07-25
SU table access was incorrect in some routines
including widely used ones 2013-07-29
SPFLG had a gridding counter which could overflow
with modern data sets 2013-08-16
PRTAB had formatting issues with required E
formats in F-format modes 2013-08-23
CVEL were affected by a bad
variable in setting the Doppler velocity and the former omitted
the system velocity when setting source velocities.
ISPEC on an image with an
could fail 2013-10-24
With the advent of the binary versions of AIPS, it has become more
difficult to compile special local tasks. If one wants to do this and
also take advantage of the improved performance of the NRAO-purchased
compilers (Intel for LINUX, LNX64, and MACINT; IBM for MACPPC; SUN for
Solaris), the user must purchase the compiler(s) for himself. This
can be rather expensive. There are two ways out of this bind. If the
local task is of sufficient interest, you could try to pursuade the
AIPS group to include it in the general AIPS distribution. This
requires the code to be written up to a least some minimal standard.
A recent example is
ATLOD which translates older Autralia
Telescope data into AIPS. The alternative is to send the code and
help file to the AIPS group and ask them to compile to routines,
leaving the results on the AIPS ftp site. This has now been done for
ORFIT in a CfA directory
CALIV in a WSRT directory.
Both of these site directories are located in a
directory at the main AIPS public ftp site.
The load modules are stored under the name
.EXE.arch to identify the operating
system (arch) to which the load module corresponds. To
install them in your system, copy the help file
$TST/HELP/ and copy
the appropriate load module to
that one has to rename the load module dropping the architecture
string. For LNX64 machines two load modules are provided, one
compiled with the gnu compiler and one with the intel compiler. In
general, for a binary installation, you will want the intel version.
... will be of interest to you if you want the latest
31DEC16 versions updated nightly,
weekly, or occasionally. It can do either text or binary updates
depending on which sort you did with install.pl.
The WENSS/WISH files have been corrected (2 July 2004) to omit the
sources which are the sum of other "components" also appearing in the
lists. Note that the survey files shipped with AIPS releases include
the shorter lists of the stronger sources. The full lists are only
available from this ftp site.
AIPS Memos, Reports, old AIPSLetters, the Cookbook, Going
AIPS, access to the newest versions of the
CHANGE.DOC and more. The most recent AIPS Memos
- number 122,
discussing the usage of AGAUS and ZAMAN spectral absorption modeling tasks,
dated March 7, 2017,
- number 121,
discussing the usage of the UFLAG gridded data flagging task, dated
September 12, 2016,
- number 120,
discussing the usage of the TVSPC data exploration task,
revision dated July 22, 2017,
- number 119,
discussing the usage of the TVSAD Gaussian modeling task, dated
December 15, 2014,
- number 118,
discussing the usage of XGAUS, ZEMAN, and RMFIT spectral modeling tasks revision dated November 8, 2017,
- number 117,
discussing the detailed FITS format used by AIPS, revision dated February 16, 2016,
- number 116,
discussing new RFI mitigation options in AIPS, dated June 2010,
- number 115,
discussing new auto-boxing for Clean capabilites in AIPS, dated June 29, 2009,
- number 114,
re-stating the FITS-IDI convention with corrections and added
tables, revision dated February 16, 2016,
- number 113,
discussing a "new" geometric way to handle the W problem, dated May 22, 2009,
- number 112,
discussing the AIPS pipeline for VLA data reduction, dated March
- number 111,
discussing phase referencing with more than one calibrator using
ATMCA, dated January 6, 2005,
- number 110,
discussing strategy for removing troposppheric and clock errors
using DELZN, revised October 21, 2009, dated August 31, 2004,
- number 109,
discussing AIPS on DVDs and read-only data systems, dated
January 20, 2004,
- number 108,
discussing weights for VLA data, dated January 21, 2003,
- number 107,
discussing the differences between FRING and KRING, dated April
- number 106,
discussing the Brandeis scheme for making movies in AIPS dated
June 6, 2001,
- number 105,
discussing the new RUN file to simplify VLBA data reduction
dated February 28, 2001 and April 26, 2001,
- number 104,
discussing the new Y2K performance test dated September 8, 2000, and
- number 103,
discussing data weighting in AIPS dated 2000-03-21.
The AIPS group maintains three e-mail exploder lists. The first,
called daip, is restricted to immediate members of the AIPS group and
a few NRAO scientist advisors. The other two are, however, open to
any suitable person. Membership is moderated, of course, because SPAM
has become so annoying.
The group intended for discussion of AIPS issues is called
bananas and is used, among other things, to announce patches
to the "frozen" versions of AIPS. Traffic is light. You can subscribe
yourself to this list on-line.
The group intended for discussion of problems related to the
"Midnight Job" is called mnj and is used to announce AIPS
Manager things related to the current MNJ. Traffic is light, but the
announcements can have a serious impact on any site attempting to stay
current with the development version of AIPS. You can subscribe
yourself to this list on-line.
The FITS Interferometry Data Interchange
format is a set of FITS
binary table definitions and a set of conventions for using them to
transport radio interferometry data between different software
The FITS Interferometry Data Interchange Convention (formerly Format)
has been accepted as an IAU-acknowledged convention. This convention
was documented by Chris Flatters in AIPS
Memo 102 which, unfortunately, was not accompanied by an editable
text version. Therefore, Eric Greisen had to re-type the document.
While doing so, he updated some matters, corrected minor wording
issues, and added 5 new sections for 5 new tables, 3 of which are
actually in use. Interested parties should review AIPS
Memo 114 revised (ps) or AIPS
Memo 114 revised (pdf); it has been submitted to the IAU FITS
Committee. Greisen has attempted to highlight the changed parts in
red in this draft. The current draft is dated August 2011 and
includes the MODEL_COMPS table and comments from Lorant
Sjowerman, Bill Cotton, and others. Please e-mail
firstname.lastname@example.org with comments.
Help for the weary AIPS Installer. Very much experimental and
incomplete, and probably needs updating, but better than nothing.
The AIPS Benchmark was known as the "DDT" (Dirty
Dozen Tasks); we have results for a variety of systems. A more modern
test called "Y2K" has been developed in 2000 to test faster
computers and to use IMAGR rather than MX. For 31DEC04 we have new master images and data sets. In
addition, we have a new HUGE test using multi-resolution IMAGR on
Cygnus A. Changes to CALIB and VTESS in particular
forced this update, while faster computers make Y2K LARGE run in as
little as 5 minutes.
The former designated-AIP-of-the-week program; rotation has been
halted due to the lack of personnel. The e-mail address
email@example.com) was the best method of reaching all
the members of the AIPS Group and will still work. However, we ask
you to use the new NRAO-wide helpdesk instead. Go to
and login with your my.nrao.edu username and password. There you may
peruse the "knowledge base" (currently empty), enter new tickets in
any of several departments including AIPS, and review and update any
tickets you have submitted.
AIPS is copyrighted by Associated Universities, Inc. using the GNU
copright form. The full text is available with every AIPS release and
may be read here.
This is the Flexible Image Transport System, and is the
standard data interchange format used by most Astronomical Software,
including AIPS. Follow the above reference for a very extensive
set of documentataion, including a large resource list for Astronomy on
The primary AIPS address is the
referenced on our main Contact page, and general
queries, requests for distribution tapes, documents, ftp access, and so on
should be directed there. Application-oriented questions should be
directed to the Designated AIP.
Modified on $Date: 2017/11/16 17:55:15 $
Eric W. Greisen