by Christoph Petermann and Armin Quante (2nd Version 24 October 1999)

Some information

The evening sky of 15 October 1999 was very clear. So I invited Armin Quante of Eckernfoerde to bring his 150 mm Kutter-Schiefspiegler along and try out making Jupiter and Saturn images with my PS39 webcam. I also took my 150 mm f5 Newton and the complete Pentium 133 PC outside.

We made a huge number of images of Jupiter in focal mode and with ocular projection. I stored the images in uncompressed JPEG format to preserve maximum information. Most images are made in black and white mode and a minor number was taken in colour mode. I used the maximum non-interlacing mode of the camera, which has 240*320 pixels. The camera has a blue filter in front of the CCD chip. This filter seems to have some errors resulting in funny stripes in the images. I have to take the filter out and correct the colours per software.

All images are made between 1900 and 2130 UT on 15 October 1999.

Results

We first pointed the Kutter on Capella for to find the right focus. The star was too bright for this purpose. We found, a star in the order of magnitude 8 is better for adjustment. After turning the scope to Jupiter we were overwhelmed by the first image showing already fine details.

In ocular projection mode it was difficult to find the planet again, but once found we could already see details of the atmosphere in the raw images. We took still images and as soon as we found one to be good enough it was stored.

Limiting magnitude in the images seems to be around 10.4.

Comparing the Newton with the Kutter it seems I need to invest some work into the adjustment of my Newton scope. As the Kutter has 4 times the focal length of the Newton it obviously has less astigmatism and coma. The only image here with the Newton is the first image showing Jupiter with its four brightest moons.

Image processing

To get the most out of your images, you may do some careful processing. The software I use for processing is Picture Window (for Windows); Paint Shop Pro 5.01 (for Windows) and GIMP (LINUX).
I added the raw image with Picture Window, which has a facility to align the image at up to 4 points. This should be done carefully. You can zoom into the image to find the right points. I use the BLEND function and set each amount to ca. 60%. After combining two or more image you may do some slight unsharp masking. This tools is also available in Picture Window.

The f5 150mm o.d. Newton (left) & The f15 150mm o.d. Kutter Schiefspiegler (right) telescope

Jupiter with the four moons (Newton) From right to left: Ganymede (mag 4.6), Europa (mag 5.3), JUPITER, Io (mag 5.0), Callisto (mag 5.6) This is a single frame image with slight contrast enhancement only.

JUPITER

• Upper Left: Composition of 4 black and white image. Unsharp masking
• Lower Left: With 2 moon; composition of 4 images; unsharp maskin; NO ocular projection.
• Upper Right: Colour composition of 3 images; unsharp masking.
• Lower Right: Single raw frame of the image above.

SATURN

• Upper Right: Combination of 2 B&W images
• Upper Left: Composition of 4 colour frames; image slightly sharpened with unsharp mask.
• Lower Left: Best image so far with composition of 5 B&W images and unsharp masking.

Text and All Images are Copyright by Christoph Petermann DF9CY

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