Observer: Uwe Schmidtmann
Location: Brunstein Observatory, Kreiensen, Germany
Date: April 11, 1997 19:11-20:01 UT
The following composite of the comet Hale-Bopp contains two ccd-images. Both were taken with an ST5 CCD camera.
The left image was taken using a Maksutov telefoto lens with 10cm apperture and f/10 (1m focal length). The Maksutov was used in prime focus. 4 images of 0.75 seconds have been added using the track and accumulate mode from CCDops, the camera control software. The upper image is scaled logarithmically, while the lower one shows the core region with extremly enhanced contrast. To achieve this, two images have been created by shifting the original image by 3 pixel in vertical direction - one up, the other one down. Then the original image was multiplied by two and both shifted images were subtracted.
The right image has been taken using a 24mm canon lens. The field of view is abt. 30 arcminutes. The gradient in the background has been "created" by the nearby moon. Because of the moonlight the gas tail is barely visible. The upper image again is logarithmically scaled, the lower image is created using rotational shift differencing (see http://www.geocities.com/CapeCanaveral/Lab/3388/rotation.html). The rotation angle was 7 degrees.
The images have been taken from the Brunstein Observatory, Kreiensen, Germany.
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