Why convert FIT to BMP?
FITS (Flexible Image Transport System) is a scientific image container storing raw detector counts as 16-bit or 32-bit integer pixel values - a dynamic range far exceeding BMP's 8-bit-per-channel limit. Exporting to BMP is useful when an older Windows application or specific lab or print workflow requires an uncompressed bitmap. For general sharing, PNG produces identical visual quality at a much smaller file size.
How to convert FIT to BMP
SAOImageDS9 FREE
Open the .fit file, set the stretch in the Scale menu (Log, Sqrt, or Linear), then export via File > Export > BMP.
XnView MP FREE
Open the .fit directly in XnView MP (which reads FITS natively) and use File > Export to save as BMP; adjust levels if the automatic stretch does not look right.
ImageJ OPEN-SOURCE
Open the .fit in ImageJ, apply Brightness/Contrast adjustment, then use File > Save As > BMP to export.
Programs that convert FIT
About these formats
.FIT
Flexible Image Transport System (FITS) image
A .fit file is a FITS (Flexible Image Transport System) astronomy image - the standard scientific data format used by telescopes, astrophotography cameras, and research archives since 1981.…
Open .FIT details →
.BMP
Windows Bitmap Image
A BMP file is a Windows Bitmap - a simple, usually uncompressed raster image developed by Microsoft. Every major OS and image viewer opens it with no extra software (double-click works).…
Open .BMP details →Quality & what to watch
- A stretch step is required before export - FITS pixel values span a much wider numerical range than BMP can hold, and the stretch determines which tones appear in the output.
- BMP is uncompressed; PNG produces a smaller lossless file at identical visual quality and is preferable unless BMP is specifically required by the receiving application.
- The original
.fitretains all raw scientific data; the BMP is a visual snapshot only.
