---
name: "image2xy"
section: "1"
platform: "linux"
package: "astrometry.net"
version: "0.97+dfsg-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/image2xy"
---

# image2xy(1)

Source extractor.

## NAME

image2xy - Source extractor.

## SYNOPSIS

**image2xy** \[options\] *fitsname.fits*

## DESCRIPTION

Read a FITS file, find objects, and write out X, Y, FLUX to fitsname.xy.fits.

## OPTIONS

- **-e** *extension*

  Read from a single FITS extension

- **-O**

  Overwrite existing output file.

- **-o** *file*

  Write XYlist to given filename.

- **-L** *order*

  Lanczos order

- **-8**

  Don't use optimization for byte (u8) images.

- **-H**

  Downsample by a factor of 2 before running simplexy.

- **-d** *factor*

  Downsample by an integer factor before running simplexy.

- **-D** *factor*

  Downsample, if necessary, by this many factors of two.

- **-s** *scale*

  Set median-filter box size (default 100 pixels)

- **-w** *width*

  Set Gaussian PSF sigma (default 1 pixel)

- **-g** *sigma*

  Set image noise level

- **-p** *significance*

  Set significance level of peaks in sigmas (default 8 sigmas)

- **-a** *saddle*

  Set "saddle" level joining peaks i sigmas (default 5 sigmas)

- **-P** *plane*

  Pull out a single plane of a multi-color image (default: first plane)

- **-b**

  Don't do (median-based) background subtraction

- **-G** *background*

  Subtract this 'global' background value; implies **-b**

- **-m**

  Set maximum extended object size for deblending (default 2000 pixels)

- **-S** *file*

  Save background-subtracted image to this filename (FITS float image)

- **-B** *file*

  Save background image to filename

- **-U** *file*

  Save smoothed background-subtracted image to filename

- **-M** *file*

  Save mask image to filename

- **-C** *file*

  Save connected-components image to filename

- **-v**

  Verbose. repeat for more and more verboseness

- image2xy 'file.fits\[1\]'

  Process first extension.

- image2xy 'file.fits\[2\]'

  Process second extension

- image2xy file.fits+2

  Same as above

## AUTHOR

The Astrometry.net team. Principal investigators are David W. Hogg (NYU) and Dustin Lang (CMU).

## SEE ALSO

http://astrometry.net