Convert FITS to SGI
Max file size 100mb.
FITS vs SGI Format Comparison
| Aspect | FITS (Source Format) | SGI (Target Format) |
|---|---|---|
| Format Overview |
FITS
Flexible Image Transport System
Scientific image format developed by NASA and the International Astronomical Union FITS Working Group (IAUFWG), first defined in 1981. Supports 8/16/32/64-bit integer and 32/64-bit floating-point pixel data with multi-extension architecture for storing multiple images and tables per file. Includes WCS (World Coordinate System) metadata for celestial coordinate mapping. The standard data format for astronomical observatories worldwide. Lossless Standard |
SGI
Silicon Graphics Image
Raster image format developed by Silicon Graphics Inc. for IRIX workstations. Supports 8-bit and 16-bit per channel with optional RLE compression. Historically important in professional 3D graphics, scientific visualization, and film production. Standard Format Lossless |
| Technical Specifications |
Data Types: 8/16/32/64-bit integer, 32/64-bit float
Structure: Multi-extension (images, tables, headers) Metadata: WCS celestial coordinates, extensive headers Byte Order: Big-endian (FITS standard) Extensions: .fits, .fit, .fts |
Color Depth: 8-bit or 16-bit per channel
Compression: None or RLE Channels: 1 (grayscale) to 4 (RGBA) Byte Order: Big-endian Extensions: .sgi, .rgb, .bw |
| Image Features |
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| Processing & Tools |
FITS data handling with astropy and Python: from astropy.io import fits
import numpy as np
# Open FITS file with full header access
hdul = fits.open('observation.fits')
header = hdul[0].header # WCS, telescope info
data = hdul[0].data # Pixel array
# Access multi-extension data
for ext in hdul:
print(ext.name, ext.data.shape if ext.data is not None else 'No data')
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SGI image from FITS astronomical data:
from astropy.io import fits
from PIL import Image
import numpy as np
hdul = fits.open('supernova.fits')
data = np.clip(hdul[0].data, 0, 255).astype('uint8')
img = Image.fromarray(data).convert('RGB')
img.save('supernova.sgi')
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| Version History |
Introduced: 1981 (NASA/IAU FITS Working Group)
Current: FITS Standard 4.0 (2018) Status: Active, universal astronomical standard Evolution: FITS 1.0 (1981) → 2.0 (1988) → 3.0 (2008) → 4.0 (2018) |
Introduced: 1984 (Silicon Graphics Inc.)
Format: SGI RGB / IRIS Status: Legacy, declining use Evolution: SGI IRIX native (1984) → cross-platform support → legacy |
| Software Support |
Astronomy: ds9, IRAF, PixInsight, Aladin, TOPCAT
Libraries: astropy (Python), cfitsio (C), FITSIO (IDL) Space Agencies: NASA HEASARC, ESA archives, MAST Other: ImageMagick, GIMP (via plugin), Pillow (limited) |
Original: SGI IRIX workstations
Libraries: Pillow, ImageMagick, OpenCV Viewers: IrfanView, XnView, display (IRIX) Other: GIMP, ffmpeg |
Why Convert FITS to SGI?
Converting FITS to SGI format addresses compatibility with legacy Silicon Graphics workstations and their software ecosystem. Many astronomical institutions operated SGI IRIX systems for decades, and some legacy software and archives still use the SGI image format.
SGI format's 16-bit per channel support makes it one of the few legacy formats capable of preserving higher bit-depth from FITS data. This is relevant when migrating astronomical data to or from systems that use the SGI image format as their native raster format.
Historical VFX production pipelines that processed astronomical imagery for planetariums and science documentaries often used SGI format. Converting FITS to SGI maintains compatibility with these established workflows and archived project files.
The conversion reads FITS data and produces SGI files with optional RLE compression. The big-endian byte order of both FITS and SGI formats aligns naturally, and the simple flat-file structure ensures reliable data transfer.
Key Benefits of Converting FITS to SGI:
- 16-Bit Depth: Preserves FITS 16-bit data, unlike most legacy formats limited to 8-bit
- Legacy Compatibility: Essential for SGI IRIX workstations still operating in some institutions
- RLE Compression: Optional compression reduces file sizes for storage-constrained systems
- Historical Archives: Access and maintain compatibility with historical astronomical data collections
- VFX Pipeline: Compatible with legacy film production and planetarium rendering workflows
- Simple Structure: Flat file format with straightforward read/write implementation
- Big-Endian Native: Natural byte-order alignment with FITS format eliminates swap overhead
Practical Examples
Example 1: Legacy SGI Workstation Compatibility
Scenario: A research institution maintains SGI IRIX workstations for legacy astronomical software and needs to convert modern FITS data for display on these systems.
Input FITS file (hst_archive.fits):
FITS astronomical data: Resolution: 2048×2048 HST image Data: WFPC2 archival data Instrument: Hubble WFPC2 Content: Deep field observation
Output SGI file (hst_archive.sgi):
Converted SGI output: SGI IRIX native format 16-bit depth preserved RLE compressed output Legacy workstation display
Example 2: VFX Film Production Pipeline
Scenario: A visual effects studio using SGI-format texture pipelines (from legacy film production tools) converts astronomical imagery for use in a space documentary.
Input FITS file (nebula_plate.fits):
FITS astronomical data: Resolution: 4096×4096 nebula composite Data: Ha/OIII/SII palette Instrument: Large-format telescope Content: Veil Nebula supernova remnant
Output SGI file (nebula_plate.sgi):
Converted SGI output: VFX pipeline compatible Film production standard Multi-channel RGB High-quality texture input
Example 3: Scientific Visualization Archive
Scenario: A computational astrophysics lab archives simulation visualization output in SGI format for compatibility with their long-running data visualization infrastructure.
Input FITS file (simulation_output.fits):
FITS astronomical data: Resolution: 1024×1024 simulation frame Data: N-body simulation render Instrument: Supercomputer output Content: Galaxy collision simulation
Output SGI file (simulation_output.sgi):
Converted SGI output: Visualization archive format Historical consistency Simple file structure Infrastructure compatible
Frequently Asked Questions (FAQ)
Q: What is FITS format?
A: FITS (Flexible Image Transport System) is the universal astronomical data format since 1981, developed by NASA and the IAU. It stores scientific observations with floating-point precision and celestial coordinate metadata.
Q: What is SGI format?
A: SGI (Silicon Graphics Image) is a raster format from Silicon Graphics workstations, supporting 8-bit and 16-bit per channel with optional RLE compression. It was historically important in scientific visualization and film production.
Q: Why convert FITS to SGI?
A: Converting FITS to SGI is relevant for legacy SGI workstation compatibility, historical VFX production pipelines, and scientific visualization archives. It's particularly useful when working with older astronomical software that runs on IRIX systems.
Q: Does SGI support 16-bit per channel?
A: Yes, SGI format supports both 8-bit and 16-bit per channel, making it one of the few legacy formats that can preserve higher bit-depth from FITS data. This is useful for maintaining astronomical data precision.
Q: Is SGI format still used?
A: SGI format has largely been superseded by PNG, TIFF, and EXR. It remains relevant only for legacy system compatibility, historical archive access, and specific VFX production tools that still support it.
Q: What is the byte order of SGI files?
A: SGI files use big-endian byte order, matching FITS format's big-endian convention. This means no byte-swapping is needed when converting between the two formats on big-endian systems.
Q: Can SGI store alpha transparency?
A: Yes, SGI format supports up to 4 channels (RGBA), providing full alpha transparency. However, not all SGI-compatible software correctly handles the alpha channel.
Q: What modern tools can read SGI files?
A: Pillow, ImageMagick, GIMP, IrfanView, XnView, and FFmpeg can all read SGI files. Most modern image editors provide at least read support for this format.