Reference Guides
Practical, expert guides on astronomy events, astrophotography, space imagery, satellite data, and visualisation
This section collects reference-grade articles on topics we return to regularly: upcoming sky events, instrument and dataset primers, astrophotography workflows, image-licensing guidance, and tools for exploring space data in your browser.
Each guide is written to be accurate, practical, and worth bookmarking. New articles are published on a rolling schedule.
Calibration Frames Demystified: Dark, Flat and Bias Frames (and When They Matter Most)
What dark, flat, and bias calibration frames are, how they work, when they are essential, and when you can skip them — a practical guide for astrophotographers.
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Astrophotography Stacking Software in 2026: Siril vs DeepSkyStacker vs Paid Suites (Who Should Use What?)
A practical comparison of Siril, DeepSkyStacker, and paid alternatives for astrophotography stacking in 2026 — features, strengths, and which tool suits which workflow.
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Bi‑Colour Narrowband (Ha/OIII) for Beginners: A Step‑by‑Step Processing Workflow
A complete step-by-step workflow for processing bi-colour narrowband (Ha/OIII) astrophotography data, from calibration through to final colour image.
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Narrowband Filters Explained: H‑alpha, OIII and SII (Wavelengths, Use‑Cases, and Common Colour Mappings)
What narrowband filters are, which wavelengths H-alpha, OIII and SII target, when to use each one, and how colour palettes like SHO and HOO are built.
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How the Kp Index Relates to Visibility: A Simple 'Where Can I See Auroras?' Reference
A quick-reference table mapping Kp index values to aurora visibility by latitude and geographic location, with practical guidance for mid-latitude observers.
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Aurora Forecasting in Plain English: Kp Index, Alerts, and a Practical Photography Workflow
How aurora forecasting works, what the Kp index actually means, which alert services to use, and a practical photography workflow for capturing the northern lights.
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NASA Earthdata Worldview for Beginners: Reading VIIRS, MODIS and Sentinel‑1 Satellite Imagery
A beginner-friendly guide to NASA Earthdata Worldview — how to navigate the tool and interpret VIIRS, MODIS, and Sentinel-1 satellite imagery layers.
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APOD Images and Copyright: How to Tell When You Need Permission
A clear breakdown of how copyright works for Astronomy Picture of the Day images — when they are free to use, when they are not, and how to check.
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A Practical Guide to Crediting Space Images: NASA vs ESA vs Partner Credits (Without Guessing)
How to correctly credit space imagery from NASA, ESA, Hubble, JWST, and partner agencies — with clear rules, examples, and common mistakes to avoid.
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Webb Maps Uranus' Upper Atmosphere: What the 2026 Release Shows About Auroras and the Ionosphere
What the 2026 JWST Uranus atmosphere data release reveals about auroral emissions, ionospheric structure, and why this ice giant remains one of the least understood planets.
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James Webb Images in 2026: How to Read NIRCam vs MIRI (and Why the Colours Look 'Unreal')
A practical guide to understanding James Webb Space Telescope images — what NIRCam and MIRI actually detect, how colour is assigned, and why the results look the way they do.
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Eclipse Season Explained: Why Solar and Lunar Eclipses Come in Pairs (with 2026 Examples)
Clear explanation of eclipse seasons — why solar and lunar eclipses cluster together, what controls the pattern, and how the August 2026 pair illustrates the mechanism.
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Partial Lunar Eclipse 27–28 August 2026: UK Timing and How to Photograph the Umbra
UK-focused guide to the partial lunar eclipse of 27–28 August 2026, with timing, visibility, and camera settings for capturing the Earth's shadow on the Moon.
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Perseid Meteor Shower 2026: Peak Night Guide and a Simple Camera Cheat Sheet
When and where to watch the 2026 Perseids, what to expect at the peak, and a straightforward camera setup to capture meteor trails.
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Total Solar Eclipse 12 August 2026: Spain & Iceland Viewing Times, Safety, and Photography Settings
Complete guide to the 12 August 2026 total solar eclipse visible from Spain and Iceland, covering timing, safe viewing, and practical camera settings for every phase.
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