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XISF#

Extensible Image Serialization Format (XISF) is an image file format created by PixInsight. It is a free format open to contributions of anyone interested. For more detailed information about the format itself refer to pixinsight.com/xisf.

N.I.N.A. is capable of saving images in XISF format. The XISF format offers a variety of header meta information and N.I.N.A. will populate all available information into this header. A detailed list of all available Headers and their conditions is described below. Many applications can make use of these headers (e.g. PixInsight during processing).

Standard XISF Headers#

  • Version: 1.0
  • CreationTime: Time when the file is created
  • CreatorApplication: N.I.N.A. - Nighttime Imaging 'N' Astronomy

Observation Namespace#

Time#

  • Start: UTC time at exposure start

Location#

  • Elevation: Elevation (currently taken from a connected telescope)
  • Latitude: Latitude taken from the astrometry settings
  • Longitude: Longitude taken from the astrometry settings

Center#

Requires a telescope to be connected

  • RA: Current telescope's right ascension coordinates
  • Dec: Current telescope's declination coordinates

Object#

Available when a target is set inside a sequence.

  • Name: Name of object
  • RA: Right ascension of target
  • Dec: Declination of target

Meterology#

Requires a weather data source to be connected

  • RelativeHumidity: Relative humidity percentage
  • AtmosphericPressure: Air pressure in hPa
  • AmbientTemperature: Ambient air temperature in Celsius
  • WindDirection: Wind direction: 0=N, 180=S, 90=E, 270=W
  • WindGust: Wind gust in kph
  • WindSpeed: Wind speed in kph

Instrument Namespace#

  • ExposureTime: Expsure duration in seconds

Camera#

Requires a camera to be connected

  • Name: Name of camera
  • Gain: Electrons per A/D unit (only available for some cameras)
  • XBinning: X binning factor
  • YBinning: Y binning factor

Sensor#

Requires a camera to be connected

  • Temperature: actual sensor temperature (requires a cooling unit)
  • XPixelSize: Pixelsize
  • YPixelSize: Pixelsize

Telescope#

Requires a telescope to be connected

  • Name: Name of telescope
  • FocalLength: Focal length (taken from equipment options)
  • Aperture: Focal length / Focal ratio (taken from equipment options)

Filter#

Requires a filterwheel to be connected

  • Name: Current active filter

Focuser#

Requires a focuser to be connected

  • Position: Current step position

Tip

Additionally all information that is explained in the FITS description is stored using the FITSKeyword Core Element.

Compression#

N.I.N.A. offers the possibility to use compression algorithms to try to reduce the file size of your images. There are three algorithms available:

  • LZ4: This algorithm is optimized for speed. While not as potent as Zlib it is dramatically faster and will result in an acceptable amount of compression most of the time
  • LZ4HC: Basically the same algorithm as LZ4 but with a higher compression rate. A bit more computational heavy than just LZ4.
  • Zlib: This algorithm will yield the highest compression result in most scenarios, but takes a long time to process and is by far the most computational heavy algorithm.
  • The option for byte shuffling will re-arrange the actual data in an attempt to optimize it for the compression. In most scenarios this will result in a better compressed result, but is a bit more computational heavy.

Compression

Tip

For a more in depth info on how the compression works refer to the XISF Data Block Compression

Checksum#

This option will store a checksum value into the XISF file to be able to validate data integrity.

Tip

For a more in depth info on how the checksum works refer to the XISF Data Block Checksum