Titan transiting Saturn 9/20/25

Saturn's iconic rings are edge-on this year--almost invisible--but this gives an opportunity to appreciate rare shadow transits as the moons (in the plane of the rings) move directly across the face of the planet.  

titan and shadow crossing saturn
9/20/25 06:44 UTC

edge-on rings also allow better appreciation of the subtle bands on the face of the planet (color enhanced).  

Here's and animation of the transit (starting in progress) over 3 hours:

titan and shadow crossing saturn
3 hour animation
9/20/25 05:53 - 08:54 UTC

If you look closely at the animation you can see a few other faint moons dancing around the planet:

titan and shadow crossing saturn
9/20/25 06:44 UTC

Imaging details:
ZWO ASI664MC
baader IR/UV blocking filter
the sunobserver eADC 
celestron 11" Edge HD, no barlow
East Bluff, CA

9/20/25 05:53 - 08:54 UTC
34 x 90 second captures for the animation

20 x 90 second for the still frame
Shutter=~4.02ms
Histogram=~43%
gain 431
~244 fps

captured with firecapture
stacked in autostakkert (upsampled 1.5x)
combined in winjupos 
processed in registax and photoshop
animations are individual captures at 1x

processing notes
caught the transit in process.  
the seeing was not great, though improved
rings were flapping like a bird's wings.
so i'm quite happy with the final processing
at first i thought the "double black dot" was due to seeing errors, 
then realized the lower was titan and the higher, darker it's shadow
the single frame is highly processed with separate processing of the core planet, 
fringe and rings.  
i tried biggsky on Saturn it really didn't like the 1.5 upsampled version
here it is compared to registax on 1x sampling.  
seemed better than registax on the disk, but didn't handle the lower signal rings well.  

probably could have pushed the sharpening in registax, but abandoned this and went with 1.5x upsample.  

registax:

BiggSky:

final registax 1.5x upsampled,

reduced to 1x: