FITS quality analysis
Open a Seestar folder or any valid FITS dataset and review practical quality evidence instead of guessing from a preview.
Seestar FITS frame grader
Find bad frames before stacking.
If your Seestar stack is soft, noisy or full of trailing stars, the problem often starts before processing. Seestar Companion analyzes Seestar and Universal FITS sessions, helps identify weak frames, monitors live captures and gives practical stack-decision guidance before you waste time on the wrong data.
Seestar S30 / S30 PRO / S50
Universal FITS mode
Live folder monitoring
Offline-first workflow
Frame diagnostics
quality evidence before stacking
Problem
Your final stack is only as good as the frames you feed it.
A Seestar session can look promising during capture, then disappoint after stacking. The issue is often not one dramatic failure, but a mix of weak frames, wind, clouds, tracking drift, seeing changes, field rotation or frames that should have been rejected earlier.
Why are my Seestar stars trailing?
How do I filter out bad Seestar frames before stacking?
Which FITS frames are actually worth keeping?
Is this live session improving or getting worse?
Should I stack everything or only the best frames?
Can I analyze non-Seestar FITS data too?
Solution
Seestar Companion turns FITS folders into decisions.
It is not just a FITS viewer. It is a session and frame analysis tool that helps you decide what to keep, what to reject, what to monitor and what to stack next.
Stack-decision guidance
Use verdicts, confidence and diagnostics to decide whether the session is worth stacking or whether weak frames are holding it back.
Live monitoring
Watch a FITS folder while frames arrive, follow the trend and decide whether to continue, adjust or move to another target.
How it helps
A simple workflow before stacking.
The goal is not to replace your favorite stacker or processing tool. The goal is to reach that tool with better information.
Load the FITS session
Use a Seestar folder, a live capture directory or Universal FITS mode for another valid FITS dataset.
Read the quality evidence
Look at frame diagnostics, session behavior and weak-frame patterns instead of relying on one final preview.
Decide what to stack
Use stack-decision guidance to choose whether to keep going, trim the dataset or process only stronger frames.
Process with confidence
Move into Siril, DeepSkyStacker, PixInsight, AIT or another workflow knowing what the data can realistically support.
Not only Seestar
Universal FITS mode expands the use case.
Seestar Companion is optimized for Seestar workflows, but it is not locked to them. Universal FITS mode can analyze any valid FITS dataset, which makes the product useful beyond one telescope family.
For Seestar users
Review Seestar S30, S30 PRO and S50 sessions, understand why a stack looks weak and make better decisions before exporting or stacking externally.
For FITS workflows
Use the same diagnostic thinking on generic FITS folders when you need a fast quality pass before committing time to deeper processing.
Buy once
Focused software for a focused problem.
Seestar Companion is a separate product in the AIT ecosystem. It is intentionally smaller than Astro Imaging Toolbox: a fast decision tool for Seestar and Universal FITS analysis on Windows and macOS.
EUR14.99
One-time purchase. Stripe checkout. Download links and your personal license file are sent by email after purchase.
Seestar Companion is an independent product by Christian Fiore and is not affiliated with or endorsed by ZWO. "Seestar" is used only to describe compatibility. Please read the refund policy before purchase.
FAQ
Common Seestar frame-quality questions.
Short answers for users arriving from searches about bad frames, trailing stars and FITS grading.
Can Seestar Companion automatically filter bad Seestar frames?
It analyzes FITS frame quality and gives practical stack-decision guidance so you can identify weak frames before stacking. It does not destructively edit your original data.
Why are my Seestar stars trailing?
Trailing can come from tracking issues, wind, seeing, clouds, field rotation, focus problems or weak frames. Seestar Companion helps inspect the session so you can see whether the issue is isolated or repeated.
Is this only for Seestar data?
No. It is optimized for Seestar workflows, but Universal FITS mode can analyze any valid FITS dataset.
Does it replace Siril, DeepSkyStacker or PixInsight?
No. It helps you understand the data before stacking or processing. You can still use your preferred stacking and processing tools after reviewing the session.