|
|
|
|
The
Jupiter opposition in June 2019 - General
Due to the fact that one of the Team Chameleon was
allowed to spend a longer period of time in Namibia in 2019, we were able to
record a large number of Jupiteravis. In total we were able to take avis in 64
nights, the first series of pictures is from June 11th, the last from October
3rd. Altogether, several hundred raw-sum pictures came together,
the best of which we present here. Jupiter appeared
in June with an apparent diameter of 46", in the last images from late
September/early October it was only 35.5 arc seconds. The difference in
distance between Earth and Jupiter was 190 million kilometres between 10 June
and 3 October.
At the end of May
we received the news that the large red spot (GRF) was subject to strong
changes, there was even talk of a possible resolution. We have therefore
focused our attention on GRF transits.
« "Jupiter
and Ganymed on 1st August 2019, Celestron C 14 + Baader Q-Turret Barlowelement
, Baader UV/IR pass filter, recording focal length approx. 6.500mm, 300/3.000
frs, ASI 224C |
|
|
After
analysis of the images, the GRF itself showed few changes, but changes in the
southern equatorial band (SEB) and in the southern tropical zone (STrZ) were
detectable in some cases at intervals of only 48 hours (see image below
left). |
The
difference in distance between Earth and Jupiter was 190 million kilometres
between 10 June and 3 October.
Stacking Problems |
« The images on the left show the
changes in the cloud band southeast of the GRF within only 48
hours
» The
picture on the right shows the comparison of the apparent diameter of Jupiter
to the opposition (46") and mid September (35.5"). |
|
|
|
|
The
first raw avi's from June were edited with Autostakkert 2.1.0.5 by Emil
Kraaikamp. We use this software with the batch mode with best results for our
monochrome moon images. With our Jupiteravis Autostakkert showed strange
stacking errors (see picture on the left).
In the raw sum image the error was hardly visible, so it remained
unnoticed for a few days. On average, half of all raw avalanche beacons in an
evening were affected by the error. We changed/changed computer, software
version and recording camera module, but unfortunately we could not verify the
cause of the error.
Since an
email request for help from E. Kraaikamp unfortunately remained unanswered, we
used the good old RegiStax 6.1. The disadvantage is that the software does not
have a batchmode and therefore all avis |
|
of an
evening had to be edited "manually", which takes a lot of time. Advantage: the
raw-sum pictures were error-free. |
Recording
technology and image processing
From the beginning we have taken
all raw avalanches with identical acquisition parameters (gain and color
balance) with FireCapture, only exposure time and image contrast were adjusted
to the corresponding observation conditions. Also, ALL raw avalanche images
were treated with identical software and identical parameters like wavelet
sharpening and white balance until the final image was ready. In general, 3,000
single images were acquired, of which 300 were stacked avifile each. The color
scheme of the finished images was adapted to images taken with Voyager II (see
images below). Recording optics was a Celestron C14 in primary focus (f =
3,900mm), together with a ZWO ASI 224C and a Baader IR pass filter. ALL images
in the image compilations are shown at a scale of 1: 1, the image orientation
is always: South top, East right. |
|
|
The raw summation picture 300/3.000
frs |
Wavelet sharpening with
AviStack |
|
|
White balance with Photoshop |
Colouring with Voyager II
Image |
|
|
Color correction with Photoshop |
Histogram and contrast in
Photoshop |
|
|
|
|
|
|
All Images and all Content are © by Wolfgang
Paech + Franz Hofmann |