Lunar Processing workflow

Posted on by

LUNAR IMAGE PROCESSING WORKFLOW v3
SeeStar S30 Pro · PIPP → Autostakkert → LSW → Siril → GIMP

OVERVIEW

Siril handles all heavy lifting — stacking, wavelet sharpening, curves and
levels. GIMP is used only for final tonal tweaks and optional colour work.
High Pass filter has been dropped — Siril’s à trous wavelets produce cleaner
results without it.

PART 1 — SIRIL

STEP 1 — Capture & Stacking Pipeline

  • Capture video (~90 seconds) with SeeStar S30 Pro
  • PIPP — pre-process and sort frames
  • Autostakkert — stack top 25% quality frames
  • LSW (Lucky Stack Worker) — light deconvolution pass
  • Load resulting TIFF into Siril

STEP 2 — À Trous Wavelet Sharpening (Optimised Settings)

Siril’s BSpline à trous wavelets are purpose-built for astronomical image
processing and operate on linear data, making them more precise than general-
purpose wavelet tools. Values below are the result of a 5-iteration scientific
optimisation process for the SeeStar S30 Pro’s 30mm aperture.

  • Menu Path: Image Processing → Wavelets Control
  • Type: BSpline
  • Number of Layers: 6

Layer settings and what each targets on the lunar surface:

LayerValueScaleLunar Surface TargetReasoning
L11.20FinestSmallest craterlets and sensor-level micro-detailConservative — avoids amplifying noise from the 30mm aperture
L21.60FineCrater rims, ejecta filaments, fine ray structureReduced from 1.80 — original value produced an artificial over-etched look
L31.20Mid-fineSurface texture, crater floor detail, smaller ray filamentsNudged up from 1.10 — adds genuine highland terrain differentiation
L41.40MidCrater wall terraces, ridge contours, medium topographic featuresKept below L2 — higher values introduced artificiality to crater walls
L51.20LargeMaria shorelines, basin transitions, broad surface boundariesConfirmed at 1.20 — dropping to 1.00 softened maria boundaries too much
L61.00GlobalLargest-scale tonal features and overall disc shapeLeft neutral — boosting at this scale affects contrast, not surface detail

STEP 3 — Curves and Levels

  • Apply curves to separate maria from highlands and shape midtone response
  • Apply levels to set white point and final tonal balance
  • These are applied after wavelets — tonal work last, sharpening first

STEP 4 — Export from Siril

  • Export as 16-bit TIFF for GIMP, or final PNG/TIFF if skipping GIMP
  • Naming convention: YYYY-MM-DD-siril-processed-v1.tif

================================================================

PART 2 — GIMP (FINAL TWEAKS ONLY)

GIMP is now used only for finishing work on top of the Siril-processed image.
The heavy sharpening is done. Do not re-sharpen in GIMP.

STEP 5 — Final Tonal Tweaks (Optional)

Only if the Siril output needs minor refinement.

  • Levels: Colors → Levels — fine-tune white point only if needed
  • Curves: Colors → Curves — minor midtone adjustment only if needed
  • Use New from Visible for each step, not Duplicate Layer

STEP 6 — Mineral Colour Enhancement (Optional — LCh Mode & Limb Mask)

Isolates and boosts genuine surface chrominance — titanium blues in the
basaltic maria and iron-rich warm tones in the highlands. Applied last —
all luminance work must be finalised before touching chrominance.

  • Layer → New from Visible → rename to: saturation Master100, B90, C80, Y15
  • Change Layer Mode to LCh Color — locks luminance, affects chrominance only

Hue-Saturation:

  • Colors → Hue-Saturation
  • Master: +100
  • Blue (B): +90 — amplifies titanium-rich mare regions
  • Cyan (C): +80 — works with Blue to deepen mare colour signature
  • Yellow (Y): +15 — subtle warmth to iron-rich highland terrain
  • Layer Opacity: 90%

Chroma Noise Suppression:

  • Filters → Blur → Gaussian Blur → Size X/Y: 2.5–3.0 px
  • Smooths colour mottling while leaving luminance detail sharp

True-Shape Limb Masking (fringing elimination):

  • Select by Color → click black background
  • Select → Invert (lunar disc now selected)
  • Select → Shrink → 35 px
  • Select → Feather → 15 px
  • Right-click layer → Add Layer Mask → Initialize to Selection → Add
  • Select → None

STEP 7 — Save & Export

  • File → Save As → full layer stack as .xcf (master backup)
  • File → Export As → 16-bit PNG or TIFF
  • Naming convention: YYYY-MM-DD-moon-final-v3.tif

================================================================

IMPORTANT GIMP NOTES

  • Always use Layer → New from Visible between steps, never Duplicate Layer.
    Duplicate copies only that single layer’s data. New from Visible captures
    the true composite result of all layers — this is critical for accurate
    processing.
  • New from Visible creates the layer inside whatever group is currently
    active. If working near the Wavelet group, collapse or click outside the
    group first, then run New from Visible to ensure it lands at the top level.
  • If New from Visible lands inside a group, drag it out above the group in
    the Layers panel rather than re-creating it.
  • Assign a keyboard shortcut to New from Visible:
    Edit → Keyboard Shortcuts → search “New from Visible” → assign Shift+Ctrl+N

================================================================

WORKFLOW SUMMARY

Siril: Wavelets → Curves → Levels → Export TIFF
GIMP: Minor tonal tweaks (optional) → Colour/LCh (optional) → Export

OPTIMISED WAVELET SETTINGS AT A GLANCE

L1: 1.20 L2: 1.60 L3: 1.20 L4: 1.40 L5: 1.20 L6: 1.00
Type: BSpline · Layers: 6

CHANGES FROM v2

  • Siril now handles wavelet sharpening — replaces GIMP wavelet decomposition
  • High Pass filter removed — Siril wavelets produce cleaner results
  • GIMP role reduced to final tonal tweaks and optional colour only
  • Wavelet settings optimised over 5 iterations for SeeStar S30 Pro aperture
  • New from Visible vs Duplicate Layer note added
  • Wavelet group context issue documented with workaround