天王星 ALPO-Japan Latest

Uranus Image 2020/11/17(UT)

Stanislas Maksymowicz,Christophe Pellier
S.Maksymowicz,Christophe.P

---

Here is an uranus report performed last 17th november with the 154mm cassegrain under good images.
There was clearly a light shining ring on the middle of the planet disk having a vague curvature,
the accessible pole darker and the opposite hemisphere also darker,but the darkest feature.

[Stanislas Maksymowicz  Ecquevilly,France]

Since a few years, the northern polar region of Uranus is noticeably brighter in infrared than the rest of the disk (above +70° lat). 
This is also noticeable in visible light. This works allows to differentiate the albedo of each one of the two regions in 4 color bands. 
As expected, the spread of the two spectra increases towards long wavelengths (following the contrast increase) ; 
but they begin to separate already in the V band, where the processed image again reveals that the polar region is observable in that color.
In R and I, most of the brightness of the planet comes from the polar region.
The very slight difference detected in the B band is most likely to be due to the gradient of light on the disk and not to a true difference.
The stars observed to make the photometry of Mars on that nigth were too low to obtain a good photometry on Uranus, 
so I have decided to re-work from the data I obtained in 2019. On another occasion I will try to observe stars directly for Uranus.
 
 

[Christophe Pellier  Bruz City,France]

ALPO-Japan Latest Uranus Section	2020/11/19
	2020/11/12