Yes, real telescope data is available for free from public archives and from marketplace free sections. Four current sources are MOANA, the Siril sample data, the Hubble Legacy Archive and the AstrophotoMarket free section (all as of 2026-09). This page lists what each one contains.
Free sources give you real raw frames captured through real telescopes, not simulations. MOANA alone offers 120 GB of free raw data, and the AstrophotoMarket free section contains 130+ free datasets (as of 2026-09).
What free data usually does not include is curation, documentation and a consistent file structure across objects. Paid datasets sell exactly those extras.
| Source | What you get | Cost | Date |
|---|---|---|---|
| MOANA | 120 GB of free raw data | Free | 2026-09 |
| Siril sample data | Sample files bundled with Siril | Free | 2026-09 |
| Hubble Legacy Archive | Free public NASA/ESA data at hla.stsci.edu | Free | 2026-09 |
| AstrophotoMarket free section | 130+ free datasets | Free | 2026-09 |
Yes for calibration, stacking and stretching practice. The Siril sample data is bundled with Siril for exactly this purpose (as of 2026-09).
Limits appear when you need a specific target, a specific filter set or documented calibration files. That is where paid datasets earn their price.
Start with one dataset and one workflow. Download the Siril sample data or one of the 130+ AstrophotoMarket free datasets (as of 2026-09), then calibrate, stack and stretch it end to end before you touch multi-filter data.
Once your first finished image comes out of your own stack, picking the next datasets becomes a simple decision instead of a guess.
