diff --git a/moon_composite.py b/moon_composite.py
index 374a234..0c0631f 100755
--- a/moon_composite.py
+++ b/moon_composite.py
@@ -104,6 +104,48 @@ def _square_crop_to_disk(ref: Image.Image, threshold: int = 25) -> Image.Image:
     return ref.crop((left, top, right, bottom))
 
 
+def _atmospheric_sky_background(
+    sky_img: Image.Image,
+    moon_cx: float,
+    moon_cy: float,
+    moon_diam_px: float,
+) -> Image.Image:
+    """Smooth atmospheric glow on a deep night-sky backdrop.
+
+    Samples the real halo colour from a ring just outside the moon disk, then
+    builds a smooth radial gradient from that colour at the disk edge to deep
+    night-sky beyond ~2.5× the radius.  No sky-cam pixels are used directly,
+    so there is no cloud texture or foil artefact regardless of how bright or
+    hazy the original sky was.
+    """
+    arr = np.asarray(sky_img).astype(np.float32)
+    h, w = arr.shape[:2]
+    r = moon_diam_px / 2.0
+
+    yy, xx = np.ogrid[0:h, 0:w]
+    dist = np.sqrt((xx - moon_cx) ** 2 + (yy - moon_cy) ** 2)
+
+    # Sample mean colour of the real halo in a ring from 1.15× to 1.8× radius.
+    ring = (dist >= 1.15 * r) & (dist < 1.8 * r)
+    if ring.any():
+        halo_rgb = arr[ring].mean(axis=0)          # real atmospheric colour
+    else:
+        halo_rgb = np.array([80, 85, 95], dtype=np.float32)
+    # Scale to a tasteful glow level (original is often overexposed)
+    halo_rgb = np.clip(halo_rgb * 0.35, 0, 180).astype(np.float32)
+
+    # Deep night-sky colour — very dark desaturated blue
+    night = np.array([4, 6, 14], dtype=np.float32)
+
+    # Radial alpha: 1.0 at the moon disk edge (dist_norm=1), 0 at 3× radius.
+    dist_norm = dist / r
+    glow_alpha = np.clip(1.0 - (dist_norm - 1.0) / 2.0, 0.0, 1.0) ** 2
+    glow_alpha = glow_alpha[..., None]
+
+    bg_arr = glow_alpha * halo_rgb + (1.0 - glow_alpha) * night
+    return Image.fromarray(np.clip(bg_arr, 0, 255).astype(np.uint8))
+
+
 def _disk_mask(size: int, feather_px: int = 6) -> Image.Image:
     """Soft circular alpha mask the size of the reference moon image."""
     m = Image.new('L', (size, size), 0)
@@ -191,24 +233,26 @@ def composite_full_moon(
     crop = src.crop((left, top, left + crop_w, top + crop_h))
     bg = crop.resize(output_size, LANCZOS)
 
-    # ── Smooth upscaling artifacts in the sky background ──
-    import cv2
-    bg_arr = cv2.bilateralFilter(np.array(bg), d=9, sigmaColor=75, sigmaSpace=75)
-    bg = Image.fromarray(bg_arr)
-
-    # ── Where is the moon's center within the upscaled background? ──
+    # ── Moon centre in output space ──
     moon_x_in_crop = cx - left
     moon_y_in_crop = cy - top
     scale = output_size[1] / crop_h
     out_moon_cx = moon_x_in_crop * scale
     out_moon_cy = moon_y_in_crop * scale
 
+    # ── Replace raw upscaled sky with atmospheric halo on dark background ──
+    out_moon_diam = output_size[1] * moon_height_pct
+    bg = _atmospheric_sky_background(bg, out_moon_cx, out_moon_cy, out_moon_diam)
+
     # ── Load reference texture, tight-crop to disk ──
     ref = Image.open(ref_moon_path).convert('RGB')
     ref = _square_crop_to_disk(ref)
     target_size = int(round(output_size[1] * moon_height_pct))
     target_size += target_size % 2  # even
     ref_resized = ref.resize((target_size, target_size), LANCZOS)
+    ref_resized = ref_resized.filter(
+        ImageFilter.UnsharpMask(radius=2, percent=160, threshold=2)
+    )
 
     # ── Phase shadow (skip when essentially full) ──
     illum = moon_phase.illumination(when_utc)
@@ -219,9 +263,6 @@ def composite_full_moon(
 
     # ── Parallactic-angle rotation ──
     par = moon_phase.parallactic_angle(when_utc)
-    # PIL rotates counter-clockwise for positive angles; we want celestial
-    # north to end up "up" in the camera image.  Negate so the rotation
-    # direction matches image-space y-down convention.
     ref_rot = ref_resized.rotate(-par, resample=BICUBIC, expand=False)
 
     # ── Composite with feathered circular mask ──
@@ -270,6 +311,9 @@ def render_phase_closeup(
     target = int(round(output_size[1] * moon_height_pct))
     target += target % 2
     moon_resized = moon.resize((target, target), LANCZOS)
+    moon_resized = moon_resized.filter(
+        ImageFilter.UnsharpMask(radius=2, percent=160, threshold=2)
+    )
 
     # Rotate by parallactic angle so "up" on the moon matches east's sky
     if when_utc is not None: