---
name: "mHdr"
section: "1"
platform: "linux"
package: "montage"
version: "6.1+dfsg-1+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/mHdr"
---

# mHdr(1)

Connect to the IRSA service to create a header template

## NAME

mHdr - Connect to the IRSA service to create a header template

## SYNOPSIS

mHdr \[-s *system*\] \[-e *equinox*\] \[-h *height*\] \[-p *pixsize*\] \[-r *rotation*\] \[-t 2mass-band\] object\|location width outfile

## DESCRIPTION

Connects to the IRSA service **HdrTemplate** to create a header template based on a location, size, resolution and rotation.

## OPTIONS

- \-s *system*

  Specify a coordinate system.  Can be one of:

  "equatorial" or "eq" (default) "ecliptic" or "ec" "galactic" or "ga" "supergalactic" or "sgal"

- \-e *equinox*

  Specify an equinox.  Default is 2000.0

- \-h *height*

  Height (y-axis) of area in degrees.  Default is equal to *width*

- \-p *pixsize*

  Size of a pixel (in arcsec); default is 1

- \-r *rotation*

  Rotation of image; default is 0

- \-t *2mass-band*

  If the data is 2MASS, the correct MAGZP will be added to the header.

## ARGUMENTS

- object\|location

  Object string or coordinate location; should be in quotes if there are any spaces or special characters.

- width

  Width (x-axis) of area

- outfile

  Path to output header template

## RESULT

**\[struct stat="OK", count=***header-lines***\]**

## MESSAGES

- *OK*

  *\[struct stat="OK", count=header-lines\]*

- *ERROR*

  *Can't open output file outfile*

- *ERROR*

  *location parameter required*

- *ERROR*

  *width parameter required*

- *ERROR*

  *Invalid object/coordinates*

- *ERROR*

  *Couldn't find host irsa.ipac.caltech.edu*

- *ERROR*

  *Couldn't create socket*

- *ERROR*

  *irsa.ipac.caltech.edu: connect failed*

## EXAMPLES

*If a user wants to create a mosaic centered on m31, 1 degree on each side, the first step is to create a header template that describes the desired mosaic:*

- *mHdr "10.68469 +41.26904" 1 m31.hdr*

  *\[struct stat="OK", count=16\]*

*Now* **m31.hdr** *can be used by other Montage modules to generate a mosaic.*

## BUGS

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

*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: \[struct stat="ERROR", status=207,* *msg="illegal character in keyword"\]*

*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.*

## COPYRIGHT

*2001-2015 California Institute of Technology, Pasadena, California*

*If your research uses Montage, please include the following* *acknowledgement: "This research made use of Montage. It is funded by* *the National Science Foundation under Grant Number ACI-1440620, and* *was previously funded by the National Aeronautics and Space* *Administration's Earth Science Technology Office, Computation* *Technologies Project, under Cooperative Agreement Number NCC5-626* *between NASA and the California Institute of Technology."*

*The Montage distribution includes an adaptation of the MOPEX algorithm* *developed at the Spitzer Science Center.*