Astrophotography diagnosis of jupiter: Bad seeing
Processed
The Doc examined this image of jupiter (processed). Estimated overall technical quality: 7/10. 1 defect found: Bad seeing (severity 2/5).
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Info
- Cible
- jupiter
- Position
- 0h00m00s · +0°00'00"
The last quarter Moon (53 %) is irrelevant here: in planetary imaging the sky background is swamped by Jupiter's brightness, so light pollution and moonlight are non-issues. The only atmospheric parameter that matters is seeing, and it was clearly average: fine detail (festoons, white ovals, the Great Red Spot's structure) stays smoothed while global contrast is good. Aim for laminar flow windows, often in the second half of the night, and favor meridian transit to cut the air mass you shoot through.
Setup
- Type d'image
- Traitée
- Phase de lune
- Dernier quartier (53 %)
- FOV
- 1.2'
The 0.02° field is consistent with a long focal length planetary rig: Jupiter fills about a third of the frame width, which leaves room for drift without clipping the disc and lets a moon fit in the field. Sampling looks adequate, the disc is neither pixelated nor artificially soft. Without focal length, camera or barlow data I cannot tell whether your f/ratio is right: the useful rule of thumb is f/ratio ≈ 5 × pixel size in µm for a color camera. Above that you magnify blur; below it you lose resolution.
The diagnosis in detail
The verdict is simple: the image is a success and its only real limiting factor is atmospheric. The disc is perfectly circular, the limb crisp with no dark rim or color fringe, which points to correct focus, no marked atmospheric dispersion and restrained processing. Both equatorial belts are well separated, the equatorial zone shows subtle shading, and structure can be glimpsed in the NEB.
What is missing is the last layer of detail: the edges of the bluish festoons and ovals are blunted, and the boundary between zones and belts is a soft gradient where good seeing would give a sharp transition. That is typical of average turbulence, which scrambles the wavefront frame after frame; stacking averages those distortions and produces this smoothing.
The processing itself is healthy: no dark ring around the limb, no artificial grain, no garish saturation. So you are exactly at the point where progress comes from capture rather than software: more frames, stricter selection, a higher planet.
Priority actions
- Capture Jupiter as close to the meridian as possible, at maximum altitude
- Extend SER recordings to 2 or 3 minutes and stack only the best 10 to 20 % of frames
- Let the tube cool for at least 45 minutes before capturing
- Check the match between f/ratio and pixel size (rule of thumb: f/ratio ≈ 5 × pixel size in µm for color)
- Refine detail with multi-scale wavelet restoration rather than a global sharpening pass
