Hale-Bopp in Osnabrück

Hale-Bopp at the Observatory on Oldendorfer Berg

Observations taken with the telescope at the observatory of the Naturwissenschaftlicher Verein Osnabrück on Oldendorfer Berg near Melle. The telescope has 60 cm aperture and a focal length of 7,46 m, we used a SBIG ST-6 CCD camera with a field of 3'x 4'.
observer: Erwin Heiser et al., eheiser@os-net.de
image processing: E. Heiser und A. Hänel

Wide angle exposures

Conventional photos taken with various focal lengths (f=55mm and mainly f=200mm) on different slide and negative emulsions (therefore different colour hues). Paper prints were scanned, digitized and the further processed.
Photos and image processing: Andreas Hänel u. a., ahaenel@rz.uni-osnabrueck.de

Observatory and Hale-Bopp on the 1997-21-03, with fixed camera, exposed for ca. 15s. The observatory was illuminated by the moon.

Animation

of the changes in the comets head between Sept. 8th, 1996, und May 2nd, 1997

For this animation we selected those of the following exposures that have been treated with the rotation radial-shift algorithmus.

Download AVI file 900 kB
and play it with an AVI player or use an AVI plugin with your browser!

1996-05-09

5 jets emanate from the nucleus.

1996-08-09

original, exp. 30 s, without filter

rotation radial-shift algorithm.

unsharp masking (SIGMA=4 pixels).

Animations

from exposures between UT 21:19:25 and UT 22:53:53. Video processing: S. Hügelmeyer, A. Hänel.

AVI-File 616 kB: originals, exposure 20s
AVI-File 608 kB: rotation radial-shift algorithm.

1996-15-09

original, exp. 30s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1996-06-10

original, exp. 30s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-02-02

f=55mm/1:1.8, Fujichrome 400, 15s with fixed camera, Georgsmarienhütte/Holzhausen, A. Hänel

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=3 Pixel).

More informations: ESO-Hale-Bopp-Page and Observatoire du Pic du Midi.

1997-04-03

f=55mm/1:1.8, Fujichrome 400, exp. ca. 40s with fixed camera, Georgsmarienhütte/Holzhausen, A. Hänel

original, exp. 1s, without filter, with Shapley lens therefore larger angle of view.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-07-03

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-10-03

f=55mm/1:1.8, Fujichrome 400, exposure 30s with fixed camera, Georgsmarienhütte/Holzhausen, A. Hänel

1997-11-03

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking.

1997-21-03

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=5 Pixel).

1997-29-03

f=100mm/1:4, 19:30 UT, exp. 5m., Fujichrome 400, Georgsmarienhütte/Holzhausen, A. Hänel

1997-31-03

f=200mm/1:4, 19:40 UT, exp. 5m, Scotchchrome 400, Oldendorfer Berg, A. Hänel, W. Haller

original, exp. 6s, red filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-01-04

f=200mm/1:4, exp. 5m, Kodak Gold 400, Oldendorfer Berg, A. Hänel

1997-02-04

Hale-Bopp high in the sky and Mercury low near the horizon
f=55mm/1:4, exp. 20s, Kodak Gold 400, Oldendorfer Berg, A. Hänel

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-03-04

original, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-06-04

f=200mm/1:4, 21:12 UT, exp. 10m., Kodak Gold 400, Oldendorfer Berg, A. Hänel

with h + chi Perseus, f=55mm/1:4, 21: UT, exp. 6m., Kodak Gold 400, Oldendorfer Berg, A. Hänel

originalbild, exp. 1s, without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-07-04

f=200mm/1:4, 21:02 UT, exp. 6m, Fujichrome 400, Georgsmarienhütte/Holzhausen, A. Hänel

1997-09-04

f=200mm/1:4, 21:15 UT, exp 5m, Fujichrome 400, Oldendorfer Berg, A. Hänel

original, 2 x 3s exp., without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-15-04

original, exp. 5s, red filter

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-16-04

original, 2 x 6s exp., without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

1997-01-05

f=200mm/1:4, 20:30 UT, exp. 3m, Fujichrome 400, Georgsmarienhütte/Holzhausen, A. Hänel

1997-02-05

original, 2 x 10s exp., without filter.

rotation radial-shift algorithm.

unsharp masking (SIGMA=10 Pixel).

Radial and rotational shift algorithm (Larson & Sekanina)

This method has been used first by Larson and Sekanina in ApJ. 89, 571, 1984 to reveal small intensity fluctuations in the coma of comet Halley exposures from 1910. Later they used it also on CCD exposures of Halley in 1986.
This algorithm is implemented in the program MiPS of Chritian Buil and others, that we use. First the intensity maximum (brightest pixel) in the image is searched. The original picture is rotated by a certain angle (we used 10°) clockwise and counterclockwise around the intensity maximum. They are shifted by a certain amount (we used 1 pixel). These two pictures are subtracted from the original, that has been multiplied with a factor of two. By this method the strong radial intensity gradient in the coma is suppressed and smaller fluctuations like jets etc. can be recognized!

Unsharp masking

The original image is convolved with a two-dimensional Gaussian function of width SIGMA (in pixels), resulting in a smeared image (also implemented in MiPS). Subtracting this image from the original also reduces the strong radial intensity gradient in the coma and reveals smaller intensity fluctuations.

Authors of the images

Erwin Heiser, Rosengasse 9, D-49082 Osnabrück, eheiser@os-net.de
Dr. Andreas Hänel, Museum am Schölerberg, Am Schölerberg 8, D-49082 Osnabrück, ahaenel@rz.uni-osnabrueck.de

Hale-Bopp in Osnabrück

Hale-Bopp at the Observatory on Oldendorfer Berg

Wide angle exposures

Animation

of the changes in the comets head between Sept. 8th, 1996, und May 2nd, 1997

1996-05-09

1996-08-09

Animations

1996-15-09

1996-06-10

1997-02-02

1997-04-03

1997-07-03

1997-10-03

1997-11-03

1997-21-03

1997-29-03

1997-31-03

1997-01-04

1997-02-04

1997-03-04

1997-06-04

1997-07-04

1997-09-04

1997-15-04

1997-16-04

1997-01-05

1997-02-05

Radial and rotational shift algorithm (Larson & Sekanina)

Unsharp masking

Authors of the images

Links