Convert FITS to PCX
Max file size 100mb.
FITS vs PCX Format Comparison
| Aspect | FITS (Source Format) | PCX (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 |
PCX
ZSoft Paintbrush
One of the earliest PC bitmap formats, created by ZSoft Corporation for PC Paintbrush in 1985. Uses Run-Length Encoding compression and supports palettized and 24-bit color. Was widely used in DOS-era games and graphics applications. Legacy 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: 1/2/4/8/24-bit
Compression: RLE (Run-Length Encoding) Color Modes: Palette-based or 24-bit RGB Planes: 1-4 color planes Extensions: .pcx |
| 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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PCX image from FITS astronomical data:
from astropy.io import fits
from PIL import Image
import numpy as np
hdul = fits.open('constellation.fits')
data = np.clip(hdul[0].data, 0, 255).astype('uint8')
img = Image.fromarray(data).convert('RGB')
img.save('constellation.pcx')
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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: 1985 (ZSoft Corporation)
Versions: PCX v0 through v5 Status: Legacy, read-only use Evolution: PCX v0 (1985) → v5 (24-bit, 1991) → superseded by BMP/PNG |
| 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: PC Paintbrush, many DOS applications
Libraries: Pillow, ImageMagick Viewers: IrfanView, XnView, ACDSee Other: GIMP, Paint.NET |
Why Convert FITS to PCX?
Converting FITS to PCX addresses compatibility with legacy DOS-era astronomical software and embedded instrument systems. While PCX is an outdated format, specific observatory installations and vintage computing environments still require it.
Historical astronomical computing archives preserve data in formats contemporary to the observations. Converting FITS data to PCX recreates the display format that astronomers of the 1980s and 1990s would have used, providing historical context for archive exhibitions.
Embedded telescope control systems with simple RLE decoders can process PCX files with minimal CPU overhead. For autoguider displays and basic instrument readouts, PCX's Run-Length Encoding provides adequate compression with trivial decode complexity.
The conversion maps FITS scientific data to 24-bit RGB PCX format, applying appropriate stretching to visualize the astronomical content. RLE compression provides modest file size reduction, particularly effective for images with uniform sky background regions.
Key Benefits of Converting FITS to PCX:
- Legacy Integration: Essential for DOS-era observatory software and vintage computing environments
- RLE Compression: Simple compression that works well for astronomical images with uniform backgrounds
- Lossless Quality: No compression artifacts in the converted astronomical imagery
- Historical Preservation: Period-accurate format for astronomical computing archive exhibits
- Simple Decoder: Minimal CPU requirements for embedded and resource-constrained display systems
- Wide Color Support: 24-bit RGB mode preserves full color information from processed FITS data
- Pillow Support: Native Python read/write for automated conversion pipeline integration
Practical Examples
Example 1: Legacy Instrument Integration
Scenario: A vintage DOS-based spectrograph display system at a university observatory requires PCX format input for its real-time spectral monitoring software.
Input FITS file (spectra_display.fits):
FITS astronomical data: Resolution: 1024×512 spectrum display Data: Calibrated wavelength data Instrument: Echelle spectrograph Content: Stellar absorption lines
Output PCX file (spectra_display.pcx):
Converted PCX output: DOS software compatible RLE compressed output 256-color palette mode Legacy system integration
Example 2: Retro Astronomy Computing Archive
Scenario: A computing history archive converts early digital telescope observations into their original display format (PCX) for a museum exhibit on astronomical computing.
Input FITS file (vintage_observation.fits):
FITS astronomical data: Resolution: 640×480 observation Data: Photographic plate scan Instrument: Historical 48-inch Schmidt Content: Palomar Sky Survey field
Output PCX file (vintage_observation.pcx):
Converted PCX output: Period-accurate format 1990s display compatible Historical preservation Museum exhibit quality
Example 3: Embedded Instrument Display
Scenario: A telescope autoguider system with an embedded processor requires PCX format for its guide star display due to the simplicity of the RLE decoder.
Input FITS file (autoguider_view.fits):
FITS astronomical data: Resolution: 512×512 guide field Data: Autoguider camera output Instrument: Off-axis guider CCD Content: Guide star field
Output PCX file (autoguider_view.pcx):
Converted PCX output: Simple RLE decoding Minimal CPU overhead Embedded system compatible Real-time display format
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 full floating-point precision and World Coordinate System celestial coordinate metadata.
Q: What is PCX format?
A: PCX (ZSoft Paintbrush) is a bitmap format created by ZSoft Corporation in 1985. It uses RLE (Run-Length Encoding) compression and supports palette-based and 24-bit true color images. It was widely used in DOS-era applications and games.
Q: Why convert FITS to PCX?
A: Converting FITS to PCX is relevant for legacy system compatibility, particularly vintage DOS-based observatory software, embedded instrument displays with simple decoders, and historical computing archives.
Q: Is PCX still used today?
A: PCX has been largely superseded by PNG, BMP, and other modern formats. It remains relevant only for specific legacy systems, retro computing, and historical preservation purposes. For new projects, use PNG or WebP instead.
Q: What color depth does the conversion produce?
A: The conversion outputs 24-bit RGB PCX files (PCX version 5), providing full color reproduction of the astronomical data after scaling from FITS floating-point values.
Q: How efficient is PCX's RLE compression for astronomical images?
A: RLE compression works well for images with long runs of identical pixel values (like uniform sky background) but is inefficient for detailed astronomical images with noise and fine structure. Compression ratios are typically modest compared to PNG's DEFLATE algorithm.
Q: Can PCX store transparency?
A: No, standard PCX does not support transparency or alpha channels. If you need transparency, convert to PNG or TGA instead.
Q: What software can still open PCX files?
A: IrfanView, XnView, ACDSee, ImageMagick, GIMP, and Pillow can all read PCX files. Most modern image editors support PCX reading, though it's rarely used as an output format.