天王星 月惑星研究会 関西支部
Uranus Image 2004/08/17(UT)
Ralf Vandebergh(250mm Newton:ATK-2C)
Here is my latest observation of Uranus on Aug.17, 2004 at 02:38:49 UT in fact no weather for
planetary imaging,due to the passage of a short thunder storm a few hours before the observations,
but the air was in place of steady very clear now,and I imaged Uranus when it passed already
for hours its highest southern latitude,so this image was taken with Uranus relatively low in the sky,
So, in spite of the clear sky, the exposuretime was need to put up to 0,8 sec. in place of the 0,5 sec.
used for the previous results.The final result is a composite of 31 exposures.
Because there was much turbulence in the air,in combination with the higher exposuretime,makes that
this new image is not of the quality of my first one from Aug 12,
though there is an obvious bright region visible again,and normally this region is registrated
when expose Uranus at full saturation.This will be much more difficult when using short videomode
like we use on the bright planets, especially when the single frames are a bit underexposed.
The righter black&white one is the same image but now processed on very high contrast by using
the color-change and brightness buttons of photoshop.
This time I used an IR-cut filter,but a quick inspectation of the results don't show any clear improve-
ment,while the exposuretime must be clearly higher than without filter.
The colour of the Uranus image is without any enchancement of saturation control,and even very
obvious in visuall observation when using a moderate-large scope in a clear atmosphere.
[Ralf Vandebergh:neighbourhood of Maastricht Netherlands]