天王星 月惑星研究会 関西支部
Uranus Image 2004/09/08(UT)
Ralf Vandebergh(250mm Newton:ATK-2C)
Uranus on Sept. 8th,seems to show a very homogeneous disk without any obvious albedo or other
Note that also the bright albedo feature which I captured several times mid August isn't visible any
This is very mysterious,and I haven't an explanation at the time.Though it's wellknown that there
existing fast moving bright clouds in the Uranus atmosphere,but this is only a suggestion.
The used practical resolution of this image is 0,19 ´´/ pixel,and the exposuretime was 0,3 sec.
The result is a stack of 133 frames.
I correct the exposuretime on each observing session,on best compromis between seeing and
transparance.A time of 0,3 sec.is normal for a reasonable clear night,while more foggy air
needs often over 1to 1,5 sec.of exposure.
recent visuall observations:
Some days ago I had an incredible view at 1500x using the 10 inch.The disk
is very dim and as large as a punaise at this magnification, thanks good seeing it was nicely
resolved.I really saw some brightniss verations and maybe some polar flattening.
[Ralf Vandebergh:neighbourhood of Maastricht Netherlands]