View XISF files in your browser
The format PixInsight saves astrophotos in, from single frames to finished stacks. Open one right here, stretched so faint detail shows. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your picture opens stretched for your screen, as astronomy apps show it, with what the telescope and camera noted.
- Auto stretched from its own levels • Bayer data in color
- Every image and plane a page
- Show details • Object, telescope, camera, exposure and filter
- Export • Save as PNG or JPEG
About XISF
Pleiades Astrophoto made XISF for PixInsight, the app many astrophotographers process their pictures in, as a modern stand-in for FITS. PixInsight saves its stacks and masters as XISF, and capture apps like N.I.N.A. can save each frame that way too.
An XISF starts with an XML header that describes each image, its size, its sample type and its color space, with the FITS keywords the camera wrote, then the pixels, often compressed with zlib, LZ4 or Zstandard and shuffled so they pack smaller.
Filepeek reads it in your browser and stretches it the way PixInsight's automatic screen stretch does, from the picture's own levels, so faint nebulae show without burning the stars. A color camera's Bayer data is turned into color, every image is a page, Show details gives the object, the telescope, the camera, the exposure and the filter, and Export saves PNG or JPEG.
Extensible Image Serialization Format
.xisf
Format
- MIME type
- application/octet-stream
- Made by
- Pleiades Astrophoto, for PixInsight
Inside the file
- Header
- XML, with FITS keywords
- Pixels
- 8 to 64 bit integers or floats
- Compression
- zlib, LZ4 or Zstandard
- Saved by
- PixInsight and N.I.N.A.
Opens in every browser
No browser shows XISF by itself. Filepeek opens it in Chrome, Edge, Firefox and Safari.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open XISF
- WindowsPixInsight, paid • Siril reads it, free
- MacPixInsight, paid • Siril reads it, free
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I open an XISF file without PixInsight?
Drop it on this page or press Peek an XISF. It opens stretched for your screen, with nothing to install.
How do I convert XISF to JPEG or PNG?
Open it, choose Export, then Save as PNG or Save as JPEG. You get the picture stretched as it shows.
Why is my XISF dark in other apps?
Most of a sky picture's light sits in its lowest levels, so as it is it shows almost black. Filepeek stretches it from its own levels, as PixInsight's screen stretch does, and the file stays as it was.
Why won't my XISF open?
Images that keep their pixels in another file, or pack them with something other than zlib, LZ4 or Zstandard, aren't read, and say so.
Is XISF better than FITS?
For PixInsight, yes: it keeps the color space, the compression and properties FITS has no room for. To share a picture with other apps, FITS is read everywhere. Both open here.