General Caveats:

  1. See the list of supported projections for a list of projections that have been formally tested by Montage. Other projection combinations are processed at user's risk.

  2. The drizzle algorithm has been implemented but has not been tested in this release.

  3. If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error:
    [struct stat="ERROR", status=207, msg="illegal character in keyword"]
  4. The copy of the WCS library included with the Montage code is from WCSTools v3.6.4. We have not thoroughly tested (and do not support) any other version of the WCS library. If you would prefer to use your own copy of the library, you should use the most recent version available, as versions prior to 3.3.4 will result in difficulties handling the ZPN projection and processing CCD distortion parameters.

  5. It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it is safer to turn on the "level only" background matching (the "-l" flag in mBgModel.
  6. A variable definition in some of the Montage modules can cause a segmentation fault under MacOS 10.2.x, because the default stacksize limit in this OS is quite low. If you have this problem, you might want to change the stacksize limit in the shell in which you are running Montage, by either typing "limit stacksize 8M" into your shell, or adding this to your .cshrc file. If you are using sh or bash, you would type "ulimit -s 8192" to do the same thing (increasing the stack size to 8MB), and this could be put in your .profile file.




mProjectPP and mTanHdr:








Note about ANSI Compliance:

Montage uses getopt to parse command line arguments. getopt is a UNIX system utility compliant with IEEE Standard 1003.1-2001. If Montage modules are compiled with the "-ansi" switch, all but mCoverageCheck, mHdrCheck, and mSubimage will return messages such as:

mAdd.c: In function `main':
mAdd.c:144: `opterr' undeclared (first use in this function)
mAdd.c:144: (Each undeclared identifier is reported only once
mAdd.c:144: for each function it appears in.)
mAdd.c:151: `optarg' undeclared (first use in this function)
mAdd.c:165: `optind' undeclared (first use in this function)
make: *** [mAdd.o] Error 1

Montage still builds and runs correctly. The messages are returned because the header files for getopt do not declare it as external. The solution is simply to add these lines to those modules that return the messages:

extern char *optarg;
extern int optind, opterr;

They will be included in the next distribution of Montage.