Convert FITS to BMP

Drag and drop files here or click to select.
Max file size 100mb.

Uploading progress:

FITS vs BMP Format Comparison

Aspect	FITS (Source Format)	BMP (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	BMP Windows Bitmap Uncompressed raster image format developed by Microsoft for Windows operating systems since 1986. Stores pixel data in a simple, straightforward structure with optional RLE compression. Device-independent bitmap format widely supported across all Windows 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: 1/4/8/16/24/32-bit Compression: None or RLE (Run-Length Encoding) Transparency: 32-bit RGBA mode Byte Order: Bottom-up row storage (default) Extensions: .bmp, .dib
Image Features	Data Types: Integer (8-64 bit) and floating-point (32-64 bit) Multi-Extension: Multiple images and binary tables per file WCS Metadata: World Coordinate System for celestial mapping Header Keywords: Extensive ASCII keyword-value metadata Dynamic Range: Full floating-point for scientific flux data Coordinate Systems: Equatorial, galactic, ecliptic reference frames	Uncompressed pixel data storage Device-independent bitmap structure Optional RLE compression 32-bit RGBA alpha support ICC color profile embedding Bottom-up or top-down row order
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')	BMP creation from astronomical FITS data: from astropy.io import fits from PIL import Image import numpy as np hdul = fits.open('star_field.fits') data = np.clip(hdul[0].data, 0, 255).astype('uint8') img = Image.fromarray(data) img.save('star_field.bmp')
Advantages	Full floating-point dynamic range for scientific data Multi-extension architecture for complex datasets WCS metadata preserves celestial coordinate information Extensive header keywords for observation metadata Universal standard across all astronomical observatories Supported by every major astronomical software package	Universal Windows compatibility Simple, well-documented format No compression artifacts Fast read/write operations Widely supported by all image editors Lossless pixel-perfect storage
Disadvantages	Not viewable in standard image viewers or browsers Requires specialized astronomical software Large file sizes for high-resolution observations Big-endian byte order can cause processing overhead Complex multi-extension structure	Very large file sizes (no compression) Inefficient for web delivery Limited metadata support No animation capability Outdated format for modern workflows
Common Uses	Space telescope observations (Hubble, JWST, Chandra) Ground observatory data (VLT, Keck, Gemini) Sky survey archives (SDSS, 2MASS, Gaia) Solar observation data (SDO, SOHO) Radio astronomy imaging (ALMA, VLA)	Windows desktop wallpapers Legacy application compatibility Simple image storage and processing Clipboard image transfer Embedded systems with limited format support
Best For	Scientific astronomical observations with precise flux data Multi-band imaging campaigns requiring coordinated datasets Archival storage with full observation metadata Pipeline processing requiring WCS coordinate transforms	Quick astronomical image previews on Windows systems Legacy software integration for observatory instruments Uncompressed intermediate files in processing pipelines Simple format for instrument control software
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: 1986 (Microsoft Windows 1.0) Current: BMP v5 (Windows 98/2000) Status: Legacy but universally supported Evolution: BMP v1 (1986) → v3 (1990) → v4 (1995) → v5 (1998)
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)	OS Support: Windows (native), macOS, Linux Libraries: Pillow, ImageMagick, OpenCV Editors: Paint, Photoshop, GIMP, all image editors Other: Universal support across all platforms

Why Convert FITS to BMP?

Converting FITS to BMP creates uncompressed bitmap images from astronomical observation data. While BMP is not the most efficient format, its simplicity and universal Windows support make it necessary for legacy observatory instrument control systems, embedded displays, and software that requires raw pixel input.

Many observatory control rooms operate Windows-based instrument computers where BMP is the simplest format for quick image display. Converting FITS data to BMP provides instant rendering with zero decompression overhead, which matters for real-time monitoring of telescope operations.

The BMP format's straightforward pixel storage makes it ideal for debugging and verification in astronomical image processing pipelines. When investigating data quality issues, a BMP provides a guaranteed pixel-accurate representation without any compression-related questions about whether artifacts are in the data or the format.

For educational purposes and simple data visualization on Windows systems, BMP conversion offers a lowest-common-denominator format that every Windows application can open. The conversion maps FITS floating-point astronomical data to standard 8-bit or 24-bit pixel values suitable for display.

Key Benefits of Converting FITS to BMP:

Zero Decompression: No codec overhead means instant display on legacy and embedded systems
Universal Compatibility: Every Windows application and image viewer opens BMP without plugins
Pixel Perfect: Uncompressed storage guarantees exact pixel reproduction of the converted astronomical data
Simple Format: Trivial to parse and generate, ideal for instrument control software integration
Wide Color Depth: Supports 24-bit and 32-bit RGBA for full-color astronomical imagery
Legacy Support: Essential for observatory systems running older Windows versions
Debugging Friendly: Uncompressed format eliminates compression-related artifacts from data investigation

Practical Examples

Example 1: Observatory Instrument Display

Scenario: An observatory control system displays real-time spectrograph output on a legacy Windows XP instrument computer that only accepts BMP input files.

Input FITS file (spectrograph_output.fits):

FITS astronomical data:
  Resolution: 1024×256 spectral strip
  Data: Wavelength-calibrated spectrum
  Instrument: Echelle spectrograph
  Content: Stellar absorption spectrum

Output BMP file (spectrograph_output.bmp):

Converted BMP output:
  Uncompressed 24-bit BMP
  Instant display rendering
  No decoder overhead
  Legacy system compatible

Example 2: Telescope Finder Chart

Scenario: An observer generates a finder chart from a sky survey FITS image for printing on a legacy observatory printer that requires BMP format.

Input FITS file (finder_chart.fits):

FITS astronomical data:
  Resolution: 2048×2048 field of view
  Data: DSS survey plate data
  Instrument: Palomar Sky Survey
  Content: Target field with guide stars

Output BMP file (finder_chart.bmp):

Converted BMP output:
  Simple uncompressed format
  Print-ready resolution
  Clean star rendering
  Annotatable in Paint

Example 3: Quick Preview for Data Reduction

Scenario: An astronomer generates quick preview bitmaps of raw CCD frames for visual inspection on a Windows workstation during an observing run.

Input FITS file (raw_ccd_frame.fits):

FITS astronomical data:
  Resolution: 4096×4096 CCD readout
  Data: Raw bias-subtracted frame
  Instrument: CCD imager 16-bit
  Content: Science field exposure

Output BMP file (raw_ccd_frame.bmp):

Converted BMP output:
  Instant rendering speed
  No compression delay
  Full frame preview
  Compatible with any viewer

Frequently Asked Questions (FAQ)

Q: What is FITS format?

A: FITS (Flexible Image Transport System) is the standard astronomical data format created by NASA and the IAU FITS Working Group in 1981. It stores scientific image data with full floating-point precision and includes World Coordinate System metadata for mapping pixel positions to sky coordinates.

Q: What is BMP format?

A: BMP (Windows Bitmap) is an uncompressed raster image format developed by Microsoft in 1986 for Windows. It stores pixel data in a straightforward structure and is supported by virtually all Windows applications and image viewers.

Q: Why convert FITS to BMP?

A: Converting FITS to BMP is useful when working with legacy Windows systems, embedded observatory instruments, or software that only accepts bitmap input. BMP's uncompressed nature ensures zero processing overhead for real-time display systems.

Q: How large are the resulting BMP files?

A: BMP files are typically much larger than compressed formats because they store uncompressed pixel data. A 4096x4096 24-bit image produces a ~48 MB BMP file versus ~5 MB JPEG or ~15 MB PNG. Use BMP only when its simplicity or compatibility is specifically required.

Q: Is the conversion lossless?

A: The FITS to BMP conversion is lossless in terms of the final 8-bit pixel values. However, FITS files often contain 16-bit, 32-bit, or floating-point data that must be scaled to 8-bit BMP range, so the original scientific precision is reduced to display values.

Q: Can BMP store transparency?

A: BMP supports 32-bit RGBA mode with an alpha channel, though not all software correctly handles BMP transparency. For transparency needs, PNG is generally more reliable.

Q: What applications still require BMP?

A: Legacy observatory instrument control software, embedded display systems, Windows clipboard operations, and some industrial imaging systems still use BMP. It's also useful for quick testing and debugging since the format is trivially simple to read.

Q: How is astronomical data scaled for BMP?

A: FITS floating-point data is normalized to the 0-255 range using histogram stretching or linear scaling. The specific stretch parameters depend on the data content, with astronomical images often requiring asinh or logarithmic stretching to capture the full dynamic range.