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FIT PNG
File conversion

Convert FIT to PNG

Verified by Adam B.· reviewed by FE Editorial ·updated Aug 17, 2026
QUICK ANSWER
Is it possible to convert FIT to PNG?
Yes - FIT converts to PNG.

The fastest path is to open the file in SAOImageDS9 or XnView MP and export via File > Export / Save As > PNG. The critical caveat is that the stretch you apply is permanently baked into the PNG - FITS stores wide-range scientific pixel values that PNG cannot represent.

Also to PNG: QOI · APM · PBM

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Tested on macOS, Windows & Linux
Last verified Sep 2026

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Why convert FIT to PNG?

FITS images store raw scientific pixel data (often 16-bit or 32-bit floating-point) that ordinary image viewers, browsers, and most photo editors cannot open. .png is a standard lossless format supported everywhere. The usual reason to convert is sharing astrophotography results online, embedding the image in a document, or passing it to a non-astronomy editor for further processing.

How to convert FIT to PNG

SAOImageDS9 FREE

Open the .fit file via File > Open, adjust the stretch under Scale (Linear, Log, or Sqrt), then export via File > Export > PNG.

XnView MP FREE

Open the .fit file in XnView MP - it applies an automatic stretch on load - then use File > Save As and set the format to PNG.

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 →
.PNG Portable Network Graphics

A PNG (Portable Network Graphics) is a lossless raster image format. Every modern OS, browser, and image app opens PNGs natively - just double-click. The most common questions are not about…

Open .PNG details →

Quality & what to watch

  • The stretch is permanently baked into the PNG: FITS pixel values span a far wider range than PNG's 8 bits per channel can hold, so the visual compression is irreversible.
  • FITS header metadata (exposure time, RA/Dec, WCS coordinates, filter, date) is not carried over to PNG; keep the original .fit file if you need that data.
  • PNG is suited for web sharing; if you plan further editing in Photoshop or GIMP, a 16-bit TIFF retains more dynamic range than an 8-bit PNG.

Frequently asked questions

Will the PNG look like what I see in my astronomy viewer?
Yes, if you export with the same stretch applied in the viewer. The stretch controls how the wide FITS value range is compressed into PNG's 0-255 range.
Does PNG carry FITS coordinates or metadata?
No. World coordinate system (WCS) data, telescope details, and exposure information exist only in the FITS header and are not transferred to PNG.
Can I export a 16-bit PNG from a FITS file?
SAOImageDS9 exports 8-bit PNG by default. For more dynamic range, export as TIFF instead.
The `.fit` extension also appears on Garmin files - is that the same format?
No. Garmin fitness data uses .fit as well, but those files are completely unrelated and cannot be opened in an astronomy viewer.