Date: | 27.3.1996 | Time: | 02:56 UT | Exposure: | 3 x 120s |
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Field of View: | 41o x 7o | Receiver: | 20482 CCD | Filter: | Schott RG645 |
Instrument: | f=100mm, 1/2.8 | Observatory: | Hoher List | Observer: | T. Credner |
Astronomical Institutes of the University of Bonn
A mosaic of three exposures is shown, which provides an Ion-tail with 41 degrees length. For a real flat sky and a higher contrast an unsharp mask was subtracted. Thats the reason for the dark parts at the comets head.
But these obvious parallel bands, starting at the end of the dust-tail, are also in the original frame. It is not really sure yet, if this is just CCD-fringing, clouds or any other non-astronomical effect. This could be the so called striae, synchronic bands that were also reported for comet West 1976 VI and comet Mrkos 1957 V on wide-field images.
If you made or just have seen equivalent images of Hyakutake, please contact me ( credner@allthesky.de). Especially wide-field observations of this time are object of interest.
The
DWARF (Deep sensing Wide Angle Recording
Facility).
For the purpose of widefield imaging of cometary tail structures, a
nitrogen cooled CCD-Camera with 2048 x 2048 Pixels was used. It was developed
and buildt by the CCD-Group of the Astronomische Institute Bonn (Klaus
Reif: Vier Millionen Bildelemente, SuW 31, 300 [3/1992]). Sometimes used
for the 1.23m-telescope at Calar Alto, now the imaging optics was a small
f=100mm f/2.0 Zeiss Planar camera lens. With this optics and the 3 x 3
cm2 sized chip a large field of 17 x 17 degree2 can
be covered. See also the
DWARF page.