天王星 月惑星研究会 関西支部
Uranus Image 2004/09/16(UT)
Ralf Vandebergh(250mm Newton:ATK-2C)
Uranus polar flattening obvious
This time, a foggy air,due to ground fog,but the benefit was exellent seeing.
This means the exposuretimes should be much longer,so capturing in the videomode
was impossible for good results.Thanks the good seeing I could work in long exposuremode
and take still some sharp images.The change to capture any disk detail is less then working in
the videomode with very short exposuretimes.
But again very well visible is the polar flattening,see also the preceding images.
I used a sampling of 0.19 ´´/pixel and an exposuretime of 188x 1sec.
at the eyepiece
Because the seeing was so good I spend some time to observe the Uranus disk
at 300x,with an exellent 4mm orthoscopic eyepiece from University optics.
Now the disk was impressive sharp,I saw the polar flattening well at this
magnification.Because the air was so foggy,I couldn't use a higher magnification.
Though the obvious color of Uranus was still impressive.
[Ralf Vandebergh:neighbourhood of Maastricht Netherlands]