Planet observation with near
infrared light

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Projectmanager/Author: Silvia Kowollik
Page 3
Update: 02.06.2008

On 02.06.2008 a test with all at present available filters with the camera DMK 21AF04.AS took place at Jupiter.

Some clouds and strong turbulences in the atmosphere produced mad conditions. The original focal length (8 meters) of the 80 cm mirror telescope was reduced by a shapley lens to 5 meters.

Purpose of the test was the determination of the exposure times with the filters.

  Jupiter on 02:20 UT with 665 nm,
Exposure time = 1/154 seconds each Singleframe, 10% of 3.000 frames used.
  Jupiter on 02:26 UT with 800 nm,
exposure time = 1/15 seconds each singleframe, 10% of 3.000 frames used.
  Jupiter on 02:35 UT with 890 nm, (methanebandfilter, FWHM = 12 nm),
exposure time = 0,5 seconds each singleframe, 50 % of 500 frames used, dark subtraction, contrast enhanced Gamma=0,9.

The Great Red Spot and "Red Jr." are shown as bright spots, while the 3. red spot in the SEB looks only very dimm. This might be a result of the mad seeing.

  Jupiter on 02:52 UT with 1000 nm,
exposure time = 0,25 seconds each singleframe, 50 % of 1000 frames used.
  Jupiter on 03:03 UT with UV-filter,
exposure time = 1/15 seconds each singleframe, 10% of 2.500 frames used.

The treatment of the pictures was divided into 4 steps:

- dark subtraction
- subpixelexact averaging
- contrast rise
- sharpening

With suitable weather conditions further tests during daytime with IR-Filters are accomplished in  june 2008 at the observatory.

In September 2008 Uranus will be seen at the night sky and we will observe Uranus during the following month to detect clouds on the planetray disk.

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