Hub of the Astrophotographes : Easy Astrophotography
Youtube guide : The smart planner
Now in 6 languages : French, English, Spanish, Italian, Deutsch and Chinese.
Hi everyone,
You're familiar with the SSI Session Planner, which has over 7,200 sessions scheduled by astrophotographers worldwide (5,500 visitors). It now features a new, customizable horizon generator that can be exported in HRZ format.
I wanted to share a tool I've been working on for months, built for the astrophotography community. Full transparency upfront: it's a recent project and the development is AI-assisted — but the tool is fully functional (over 6,500 planning sessions generated since early January) and completely free in its web version.
StellarSkyImager Planner — SSI Session Planner
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The concept
You enter your observation site, your setup, and your session window. The planner returns a scored and ranked list of targets that are genuinely visible that night, from your exact location. Each target includes its precise position within its constellation, so you can find it quickly in the sky. Not a generic list — your list.
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The scoring engine
Each target receives a score calculated from a combination of factors:
Altitude above your horizon during your session window — or better, above your custom horizon profile
Moon phase, illumination and angular separation
Your site's Bortle class, automatically retrieved from a sky quality grid (if data is missing for your location, you can enter your Bortle class manually)
Framing quality relative to your actual field of view — focal length, sensor, pixel size, binning
Surface brightness vs. light pollution interaction
Spectrum / filter compatibility — in narrowband, objects that actually emit in Hα, OIII or SII are scored higher
Weather forecast for your planned night
This isn't "is the object above the horizon." It's "is it worth imaging tonight, with my gear, under my sky."
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Planning features
Sequential planning — build a complete session with targets ordered over time, exportable to NINA
Multi-filter mode — plan a session across the same night, with and without moonlight using different filters
Dobson guiding mode — designed for alt-az tracking with automatic field rotation management
Interactive framing — move and rotate the framing of each target before export, to match your exact composition
Altitude graph — visualize every target's trajectory across the full night
Polar chart — sky map view of your planned session
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Available catalogs
Messier, NGC, IC, Arp (338 galaxies), Abell planetary nebulae, SNR, Sh2 and HASH — all integrated, all scored.
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Horizon Generator
Draw your real horizon profile directly in the tool, including a maximum ceiling altitude if you're imaging from a balcony or terrace. Export it as a .hrz file for NINA, or import it directly into the planner so every score and visibility window reflects your actual sky.
SSI Horizon Generator : SSI Horizon Generator
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Export
When your plan is ready, export it to:
NINA
ASIAIR
EKOS (testers needed)
APT (testers needed)
PDF — printable session sheet
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Free, browser-based, no account required. Your configuration can be exported as JSON.
Available in French, English, German, Spanish, Italian and Chinese (AI translation).
The tool is young and development is ongoing. Community feedback is what will shape the roadmap. If you try it and find something broken or missing — I'm all ears.
StellarSkyImager
Planner: www.stellarskyimager.frSSI Session Planner