“From Compressed to Cosmic: How to Use jpeg2fits for Astronomy Data” outlines a workflow for converting common, compressed JPEG images into FITS files, which is the universal data format used by professional astronomers.
While you can easily convert a data-rich FITS file into a JPEG to share it online, going backward from a JPEG to a FITS file requires special care. JPEG images are “lossy,” meaning they throw away valuable scientific data to save space. Converting a JPEG into a FITS file allows you to view and manipulate a standard photo using powerful astronomy tools. 🌌 Why Convert JPEG to FITS?
Software Compatibility: Professional astronomy programs like SAOImage DS9 or Python libraries like Astropy require FITS files to open and display images.
Testing and Practice: It allows students and amateur astronomers to practice digital image stretching, color composting, or background calculations without needing a telescope.
Adding Metadata: FITS files have a “header” that acts like a digital label. You can type in coordinates, telescope types, and exposure times directly into the file. 🛠️ How to Use jpeg2fits (The Core Steps)
You can write a simple Python script using Astropy or use standalone command-line tools to achieve this conversion. 1. Read the Compressed Image
The tool first reads the JPEG image and breaks it down into raw numbers. A standard color JPEG is broken down into three main channels: Red channel array Green channel array Blue channel array 2. Convert Data Types
JPEGs store brightness values as simple integers (usually from 0 to 255). The conversion process scales or converts these values into floating-point numbers so astronomical software can process them properly. Efficient Lossless Compression of Integer Astronomical Data
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