A black hole on Neptune?

You'd think it would be on uranus, but there's a black hole on neptune: the Great Dark Spot is thought to be related to a storm, similar to the persistent great red spot on jupiter. there's also occasional cloud activity on the surface of neptune.  both are extremely difficult to detect as it's quite distant.  

Here's a shot of neptune on the same night i shot uranus, using the same processing techniques.  
Definitely a bit of a stretch, but with a little imagination you can see a subtle dark section in the center and a white patch just below and to the right:

Neptune 10/27/2018 06:17 UTC IR-RGB

also seen to the lower right is neptune's moon triton.  

I'd say the white patch is more convincing, but can't call either more than wishful thinking/artifact at this point.  If nothing else, it's a nice shade of blue ;)



Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters
Baader IR pass 685 nm
celestron 11" Edge HD
East Bluff, CA
10/27/18 06:17 UTC
120 second captures, 2x each filter (3 for IR)
gain 456 , exposure ~51 ms red, 19 ms green, 23 ms blue, 100 ms IR 685 <30% histogram
upsampled x2 in autostakkert, derotated in winjupos.
color balance on triton
composite image to bring in triton (present even on short exposures, but faint)

clouds on uranus

what better follow up to methane on jupiter than clouds on uranus? 

prior blog entry: "there's not much to see visually.  bluish-green, it can be seen with the unaided eye in dark locations.  At high power it can be seen as a small disk rather than a dot.  A monster telescope or camera might detect several moons, and possibly faint cloud formations..."

to my surprise, an IR filter was able to bring out cloud cover on the upper half:

Uranus IR-RGB 10/27/2018 08:52 UTC

have to try a methane filter on this one ;)



Imaging details:
camera ZWO ASI 290MM with ZWO RGB filters
Baader IR pass 685 nm, Astronomik IR pass 807 nm
celestron 11" Edge HD
East Bluff, CA
10/27/18 8:52 UTC
120 second captures, 2x each filter (only one for IR 685)
gain 456 , exposure ~13 ms red, 4 ms green, 6 ms blue, 130 ms IR 807 30% histogram
upsampled x2 in autostakkert, derotated in winjupos.
color balance eyeballed ;)
(actually set the white point to the clouds)


here's the straight RGB for the purists:

Uranus RGB 10/27/2018 08:52 UTC

References:
interesting articles by Christophe Pellier on the spectrum of uranus and implications for IR filters:
https://www.planetary-astronomy-and-imaging.com/en/uranus-spectrum-commented
https://www.planetary-astronomy-and-imaging.com/en/filters-uranus-spectroscopy