Saturn: Enceladus in transit and a cross-checked white spot

Image Title: Saturn: Enceladus in transit and a cross-checked white spot

Copyright: Makrem Larnaout & Hafedh Driss

Date image was taken: July 31, 2026

Location: Tunis, Tunisia

Data Acquisition Method: Personal Telescope Setup

Description and Details: A bright feature in the northern hemisphere, confirmed on two independent setups with matching position and morphology.
Telescope 1: SkyWatcher Dobsonian 16" + GreatStar ADK (modified eADK, Arduino based auto correction/autopilot) + Televue Powermate x4 + Player One C II (color) + Baader UV/IR cut filter + Player One M II (mono) + Sloan S'. 30 min integration.

Telescope 2: Celestron C14 EdgeHD + GreatStar ADK (modified eADK, Arduino based auto correction/autopilot) + Televue Powermate x2 + ZWO ASI462MM (mono), IR 642nm and Sloan R' filters. 30 min integration.

2 telescopes, 3 cameras, 4 filter configurations, consistent detection across all of them. IR642 penetrates deeper into cloud opacity layers, R'/S' are more sensitive to high altitude Rayleigh scattering; presence across both bands points to a vertically extended structure rather than a simple albedo variation, consistent with a small scale convective cell/storm tied to seasonal NH activity.

Rings: the B ring shows fine internal structure with faint radial spokes, alongside a clean, well defined Cassini Division separating it from the A ring.

Moons: Enceladus in transit, Tethys and Mimas visible to the east.

by Makrem Larnaout, Daniel H. DRISS

Published: Aug 2, 2026

Total integration: 6m 40s

Integration per filter:
- UV/IR Cut: 1m 40s (10000 × 0.01")
- Planetary: 1m 40s (10000 × 0.01")
- Photometric R: 1m 40s (10000 × 0.01")
- Baader SLOAN/SDSS-z_s' 1.25": 1m 40s (10000 × 0.01")

Equipment:
- Optics: Celestron EdgeHD 14", Sky-Watcher DOB 16" SynScan
- Cameras: Player One Mars-C, Player One Mars-M II, ZWO ASI462MM
- Mounts: JTW Astronomy Trident GTR, Sky-Watcher Dobson telescope N 305/1500 Skyliner FlexTube BD DOB GoTo
- Filters: Astronomik ProPlanet 642 BP IR-Pass 1.25", Baader SLOAN/SDSS-r' 1.25", Baader SLOAN/SDSS-z_s' 1.25", Baader UV/IR Cut / Luminance 1.25"
- Accessories: Greatstar ADK, Tele Vue 2x 1.25" Barlow (BLW-2125), Tele Vue 4.0x 2" Powermate (PMT-4201), ZWO EAF, ZWO EFW 7 x 2″, ZWO EFW mini (5 x 1.25″ / 5 x 31mm)
- Software: Adobe Photoshop, Emil Kraaikamp AutoStakkert!, Grischa Hahn WinJUPOS, Pleiades Astrophoto PixInsight, Torsten Edelmann FireCapture

Name: Makrem Larnaout

Website or Facebook Profile: http://www.facebook.com/makrem.larnaout