Venus Image 2023/09/13(UT)
Antonio Cidadao
A.Cidadao
| Antonio Cidadao |
Eight independent SERs were obtained (see table below for identification no., SER duration, frame exposure, gain setting, and UT time). From each SER a 100% stack was obtained, subsequently processed in Astrosurface (my usual procedure; all stacks were similarly processed). The 8 stacks (identified "01" to "08" in the image and gif animation) were confirmed to be registered, and then averaged, in MaxIm DL (producing a master "stack"). A gif animation was also produced from the individual eight independent stacks, plus the master stack, to evaluate/discriminate features that were present in all data, from those that should be interpreted as noise-related, and also from the partial aperture blocking from the observatory wall (this progressively disappeared as the planet became higher in the sky). Please also notice that the changing aspect of the Venus illuminated crescent, between independent stacks, has at least three factors involved (camera exposure and gain, obviously, but also the percentage of the telescope aperture that, at the time, was not blocked by the observatory wall). The constant detection of various dark features in the Venus NS, in all independent stacks and also in the averaged master stack is in my opinion well depicted. The same occurs with a brighter patch at the NPR (arrow in the image). With respect to the dark features, they are only partially coincident to the WinJupos simulation map, raising the possibility of dense intervening clouds. With respect to the brighter NPR patch, perhaps a decreased opacity of the cloud coverage over the low terrain therein, could explain the phenomenon. Hope that comparing data obtained by other observers can elucidate the above hypothesis (#) duration exposure gain UT time 01 300sec 100ms 200 05:04_3 UT 02 300sec 100ms 150 05:10_3 UT 03 300sec 200ms 150 05:16_3 UT 04 300sec 100ms 100 05:22_6 UT 05 300sec 200ms 100 05:28_1 UT 06 300sec 100ms 100 05:33_7 UT 07 900sec 100ms 150 05:44_0 UT 08 300sec 800ms 0 05:54_4 UT
≪アントニオ シダダオ ポルトガル≫ [Antonio Cidadao Oeiras - Portugal]
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Venus Section
2023/09/14
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