V. 24.1.2005 The Digital Bochum Halley Archive W.E. Celnik (1), P. Koczet (2), W. Schlosser (3), R. Schulz (4), K. Weissbauer(3) (1) Graudenzer Weg 5, D-47495 Rheinberg, Germany (2) Am Lockvogel 1, D-58452 Witten, Germany (3) Astronomisches Institut, Ruhr-Universität Bochum, D-44780 Bochum, Germany (4) ESA/ESTEC, Postbus 299, NL-2200 AG Noordwijk, Netherlands Abstract The Bochum archive of plates and films of comet 1P/Halley 1986 has been digitized for public use. The aims of the observational project are described as well as the techniques used: cameras, emulsions, optical filters, and calibration. A description of the long-time storage of plates and films is followed by a sample of "bad" images and the reasons for the poor quality of some images. The scanning procedure is described and a list of publications till 2004 based on images from the Bochum archive is presented. 1. The Bochum Halley Project 1986 Comet 1P/Halley was observed photographically from February 17 to April 17, 1986 at the European Southern Observatory on La Silla by a group of the Astronomical Institute of the Ruhr-University of Bochum: Conception of the observational project was established by W. E. Celnik, P. Koczet and W. Schlosser. The photographic work using special equipment described below was done by R. Schulz, W. Schlosser, and K. Weissbauer. Additional photoelectric measurements were made by W. E. Celnik from February 24 to April 16, 1986, using the 61-cm-Bochum-telescope on La Silla. The observations were aimed to study the structure, dynamics and physical properties of coma, dust tail and plasma tail in full spatial extent, as well as their temporal evolution and interaction with the solar wind. To convert the photographic densities into relative intensities, sensitometer spots were exposed on the same photographic emulsions as the sky images and developed together with these. In addition photographic images of the galaxy M 83 were obtained each night with the same equipment as the comet images. These can be used for relative calibration purposes. This archive contains a total number of 1192 images of comet 1P/Halley (Fig. 3, 4), 195 calibration images of M 83 (Fig. 1, 2), plus a set of sensitometric spots for each observing night. All observations have been obtained from ESO La Silla, Chile, during 57 nights between 17 February and 17 April 1986. Most of the nights were of photometric quality. Each image was protocolled handwritten within an observational book and given a unique image number, beginning with "4488" for the first image on February 17, up to "6212" for the last image on April 17, 1986. The image number was also written by hand using an ink pencil onto the "clear-plate"-periphery of all images on 35-mm-film and glass plates, after development and drying. The image number is also part of the file name of each image within this archive. A complete list of all comet images obtained was published by Celnik et al. (1988). 2. Photographic instrumentation Special equipment was set up under the open sky: A very stable Alt 6AD parallactic mounting with programmable step motors in both right ascension and declination in order to follow the comet's motion automatically. Guiding on the central brightness peak of the cometary coma was controlled using an achromatic refractor f/10 with a focal length of 1000 mm providing a wide field of view (25 arcmin) and a visual enlargement of more than 150x. A Lichtenknecker Flat-Field-Camera (FFC) f/4.1, focal length 759.4 mm, was used in combination with a Canon FTB camera housing for 35-mm-film to obtain images of the head of 1P/Halley resulting in a field of view of 1.8 degrees x 2.7 degrees (Fig. 5, 7). The best angular resolution within the images of this instrument was 5 arcsec. Sensitized 103a-E, 103a-F and Technical Pan 2415 emulsions on 35-mm-film by Kodak were used. Specially fabricated optical filters (see Section 4) were set between the FFC tube and the camera housing, to distinguish different components of the comet. Four identical wide-field Hasselblad 2000 FC/M camera housings fitted with Zeiss Planar f/2.0 T* lenses of the focal length 110.8 mm (Fig. 6, 8) were used to investigate coma and tails to their entire extent. Sensitized Kodak-IIIa-F and -IIa-O emulsions on 62 mm x 62 mm glass plates were used within sheet film adapters behind each of the Hasselblad camera housings. The field of view obtained was 28.6 degrees x 28.6 degrees; the angular resolution was approximately 30 arcsec. Special comet filters (see Section 4) were mounted in front of the entrance lenses (Fig. 6). From February 25 to March 10, 1986, a Pentacon f/4 lens, focal length 300 mm, fitted to a Pentax MX 35-mm-housing was additionally used (field of view: 4.6° x 6.9°, angular resolution: 12 arcsec, Kodak 103a-F 35-mm-film). Some images were taken with a Rollei 66 SL camera with a Zeiss UV Sonnar lens (focal length 105 mm, f/4.3) on IIa-O 62 mm x 62 mm glass plates, for higher transmission at short wavelengths. 3. Emulsions Kodak delivered the IIIa-F emulsions as backed 8 inch x 10 inch glass plates of 1.016 mm thickness, Ser. No. HD1J5 CAT 129 9817. Before undergoing the sensitisation process quadratic 62-mm-plates were cut out of the large plates. The IIa-O 62 mm glass plates were supplied by ESO (Emulsion Ser. No. HD1I5 CAT 174 8862) and cut from 16 cm x 16 cm plates. All IIIa-F and IIa-O plates were sensitized by ESO La Silla staff in standard manner. The film thickness of the emulsions 103a-E and 103a-F was 0.015 mm, the film of Technical Pan 2415 has a thickness of 0.008 mm. All 35-mm-films were delivered as piece goods by Vehrenberg KG. Before each observational night these emulsions were hyper sensitized by baking in forming gas at 65 °C for 5 hours, using a pressure of 5000 hPa. All sensitisation processes remained identical during the entire observational campaign. All sky and calibration images of each single night were developed together in un-thinned Ilford Microphen Developer at 19 °C for 25 minutes. The ESO darkroom facilities within the 1.5-m-telescope building were used. The development conditions remained constant throughout the observational campaign. For the conversion of photographic densities into relative intensities, sensitometer spots were produced for each observing night and developed together with the observations. The 35-mm-film was too narrow for the complete spot distribution (Fig. 9). Some of the spots therefore overlap with the perforation holes of the film. Also a single glass plate was too small for a complete set of sensitometer spots (Fig. 10). The spot series was distributed over two adjacent plates. Table 1 gives the relative intensity scale for the ESO sensitometer spots from the "ESO Manual of Sensitometer Spot Calibration". If time was available, a series of FFC images with staggered exposure times was made (Fig. 11). The spectral sensitivities of the emulsions used are shown in Fig. 12, as available. Table 1: Relative intensity scale for the ESO Sensitometer spots, as taken from the ESO manual of Sensitometer Spot Calibration. Spot No. 11 was set to 1.00. Spot No. Rel. Intensity 1 0.093 2 0.112 3 0.158 4 0.182 5 0.257 6 0.312 7 0.373 8 0.440 9 0.620 10 0.716 11 1.00 12 1.23 13 1.41 14 1.58 15 2.28 16 3.02 17 4.02 18 4.94 19 6.07 20 7.23 21 8.60 4. Optical filters For the optical filters we mainly followed the recommendations of the International Halley Watch (IHW). The filters used and their characteristics are listed in Table 2. The plasma tail and neutral gas coma were observed with interference filters for CO+ (c.wl. 426.0 nm) and CN (c.wl. 388.0 nm) both for the FFC (archive filter code: "CO_FFC" and "CN_FFC") and Hasselblad ("CO_HBL" and "CN_HBL"). The dust tail was recorded in mainly continuum light using Schott OG 530 filters for FFC ("OG_FFC") and Hasselblad ("OG_HBL") and Schott RG 645 filter for the 300-mm-lens ("RG645"). To allow shorter exposure times for the plasma tail images, hence higher temporal resolution, one of the Hasselblad camera was equipped with a broad band filter combination of a long- and a short-wave-passband filter (archive filter code: "375_450"). The short-wave-passband filter was a custom-made interference filter (cf. Fig. 13e), the long-wave-passband filter a Schott GG 375 filter. For the same reason we took some picture sets without any filter, and several images through a GG 422 long wave passband filter cutting off the ultra-bright CN coma at 388.0 nm (archive filter code "GG410"). The Flat- Field-Camera filters measured 55 mm in diameter, the Hasselblad filters 65 mm. The custom made interference filters quoted above were manufactured by ORIEL Inc. based on specifications established by the Bochum group. Table 2: Data of photographic filters 1 2 3 4 5 6 7 CN_HBL CN EMISSION TAIL INTERFERENCE FILTER (CUSTOM) 387.7 - 4.5 40.5 CN_FFC CN EMISSION COMA INTERFERENCE FILTER (CUSTOM) 388.4 - 4.1 38.0 CO_HBL CO+ EMISSION TAIL INTERFERENCE FILTER (CUSTOM) 428.9 - 12.2 54.6 CO_FFC CO+ EMISSION COMA INTERFERENCE FILTER (CUSTOM) 428.0 - 9.6 56.1 OG_HBL DUST CONTINUUM TAIL STANDARD SCHOTT OG 530 - 540.0 - 90.0 OG_FFC DUST CONTINUUM COMA STANDARD SCHOTT OG 530 - 540.0 - 90.0 RG645 DUST CONTINUUM TAIL STANDARD SCHOTT RG 645 - 645.0 - 90.0 N2 N2+ EMISSION INTERFERENCE FILTER (CUSTOM) 391.0 - 10.4 65.0 H2O H2O+ EMISSION INTERFERENCE FILTER (CUSTOM) 659.1 - 29.4 83.0 OF COMETARY STRUCTURE WITHOUT ANY FILTER - - - 100.0 N/A COMETARY STRUCTURE WITHOUT ANY FILTER - - - 100.0 GG410 COMETARY STRUCTURE STANDARD SCHOTT GG410 - 421.7 - 90.0 375_450 IONS TAIL STRUCTURE BROAD BAND FILTER (CUSTOM) 419.2 - 88.4 70.7 CO2 CO2+ EMISSION INTERFERENCE FILTER (CUSTOM) 369.7 - 9.9 58.8 Legend to Tab. 2: 1 - Filter code used in image archive 2 - Cometary component to observe 3 - Technical type of the filter 4 - Central wavelength of interference filter or filter combination in nanometers 5 - Wavelength of transmission edge of passband filter in nanometers 6 - FWHM of interference filter or filter combination in nanometers 7 - Maximum transmission of the filter in percent Additionally some photographs were taken with the Hasselblad cameras using interference filters for H2O+, N2+, and CO2+ molecular spectral bands with the N2+ and CO2+ wavelengths lying near the short transmission limit of the Zeiss Planar lenses. Filter codes within this archive are "H2O", "N2" and "CO2" resp. 5. Storage of original plates and films Since 1986, the original plates and films are stored within an air-conditioned room with constant temperature and relative humidity. Only for the short times during investigations the original plates and films went out of the room. The glass plates are stored in a steel cupboard upright position, held at both sides by small slits within a wooden storage tool (Fig. 14). Originally each plate was put into a folded envelope of greaseproof paper with folding edges at the backside of the plate. After scanning the plates have been stored without envelopes. The 35-mm-filmstrips have been stored in customary highly transparent filmholder sheets (Fig. 15), sampled in an upright manner in another steel file cabinet. 6. Image quality Most of the 1192 images in the archive are of good quality and excellently suited for morphological analysis. However, some images suffer from the following effects: a) Non-photometric conditions in cloudy nights (Fig. 16). b) Comet in front of the Milky Way (Fig. 17). c) Moon light resulting in sky-limited exposure times and in few cases incidence of moon light into the Hasselblad optics (Fig. 18). d) Incidence of light has blackened the emulsion before, during or after exposition, more or less irregularly, e.g. by flash lights (Fig. 19). e) Electrostatic flashes on Technical Pan 2415 film. Because the film sheet is extraordinarily thin and the humidity was very low, the film has been charged within the camera housing, resulting in electrostatic flashes exposing the emulsion during transportation from one image to the next (Fig. 20). f) The emulsion on some plates shows sheet errors, black spots or voids, already from the production process (Fig. 21). g) The images show irregular fog due to production or development of the emulsion (Fig. 22). h) Optical coma, visible especially within the image corners of the 110 mm lens at f/2.0 and fitted with broad-band filters (Fig. 23). i) Optical vignetting from the centre towards the edges of the image, visible in the images of the 110 mm lens at f/2.0 (Fig. 24). j) Very few images are out of focus (Fig. 25). k) Interruption of exposure for several minutes (Fig. 26). l) Bad guiding (Fig. 27). m) Scratches on plates or films (Fig. 28). n) Irregular spots from spattered drops of water or chemicals during development (Fig. 29). o) Irregular spots or central accumulation of dark spots by effects of humidity or fungus (Fig. 30). p) Finger prints (Fig. 31). q) Broken glass plates (Fig. 32). r) The pixel values of the digitized images have been influenced by flat-field-effects during the scanning process (see Section 7). 7. Scanning procedure All the plates and films were scanned between January and November 2004 with a customary high-end flat-bed scanner, Epson Perfection 3200 photo, A4 format. The scanner was covered with a transparency light unit, format 12.0 cm x 27.5 cm. Only the central 70 mm x 200 mm of the scanner format were used for scanning. The scanning resolution used for all images was 2400 points per inch (ppi), corresponding to a spatial resolution of 10.6 æm on the emulsion. This resolution approximately equals the grain noise, only the fine-grain emulsion TP 2415 has a finer grain noise. The scanning dynamic range was 16 bit greyscale, resulting in digital brightness units between 0 and 65535. The transparency scanner area was large enough to scan two image glass plates together with the two plates showing the Sensitometer spot series during a single scanning transit (Fig. 33, 35). In a similar manner two strips of 35-mm-film could be scanned together with the film strip showing the spot series during a single scanning transit (Fig. 34, 36). Thus a Sensitometer spot file is valid for more than one image file, within the archive each spot file is related to one or more image files. The label file of each image file contains a link to the corresponding spot file. The greyscale dynamic for the scans was chosen such that always the unexposed "clear plate" of plates and films in the digital result always show a pixel value of >0. The darkest point within the coma of the comet was chosen to have a pixel value of 65535 or smaller. If possible the "clear plate" is visible in all images of the archive. The pixel values of the digitized images have been influenced by flat-field- effects during the scanning transit, which result from non-uniform illumination of the scanning area. Fig. 37 shows the flat-field of the scanning area used, in the original contrast between 0 and 65535 (top), and in unrealistic full minimum-maximum-contrast of the top 18 % of the pixel values, that is between pixel values 53970 and 65535 (bottom). Interpreting the irregularity as "noise" the standard deviation is 1.5 % around a mean pixel value of 64639 within the flat field. The irregularities should be small enough to make future photometric reductions possible. The primary scanning and storage data format was common greyscale 16 bit TIF format. During the archiving process the data format has been changed into astronomical FITS format. DVD-R's with a capacity of 4500 Mbytes resp. were used as primary storage media. 8. Chronological list of related publications 1. Celnik, W.E., Schulz, R., Weissbauer, K. (1986): Periodic Comet Halley. IAU Circular No. 4179 [CELNIKETAL1986A] 2. Celnik, W.E., Schulz, R., Weissbauer, K. (1986): Periodic Comet Halley. IAU Circular No. 4183 [CELNIKETAL1986B] 3. Celnik, W.E., Schulz, R., Weissbauer, K. (1986): The accceleration within the ion tail of comet P/Halley after the disconnection event of March 9, 1986. Astron. Astrophys. 163, L7 [CELNIKETAL1986C] 4. Celnik, W.E. (1986): The acceleration within the plasma tail, the rotational period of the nucleus and the aberration of the plasma tail of comet P/Halley 1986. Proc. 20th ESLAB Symp. on the Exploration of Halley's Comet, Heidelberg, 27-31 October 1986, ESA SP-250, Vol. I, p. 53 [CELNIK1986A] 5. Schlosser, W., Schulz, R., Koczet, P. (1986): The Cyan Shells of Comet P/Halley. Proc. 20th ESLAB Symp. on the Exploration of Halley's Comet, Heidelberg, 27-31 October 1986, ESA SP-250 Vol. III, p. 495 [SCHLOSSERETAL1986] 6. Schulz, R., Schlosser, W., Koczet, P. (1986): The Cyan shells of comet P/Halley. Bull. Am. Astron. Soc. 18, 826 [SCHULZETAL1986] 7. Celnik, W.E., Koczet, P., Schulz, R., Weissbauer, K. (1986): Die Dynamik im Ionenschweif des Kometen P/Halley und die Rotationsperiode des Kerns. Mitt. Astron. Ges. 67, 271 [CELNIKETAL1986D] 8. Celnik, W.E. (1986): Auf der Jagd nach dem Halleyschen Kometen. Sterne und Weltraum 25, 162 [CELNIK1986B] 9. Celnik, W.E., Koczet, P., Riepe, P., Schlosser, W., Schulz, R., Weissbauer, K. (1986): Komet Halley nach dem Periheldurchgang. Sterne und Weltraum 25, Title and p. 280 [CELNIKETAL1986E] 10. Koczet, P., Schulz, R. (1986): Komet Halley 1986. Sterne und Weltraum 25, 398 [KOCZET&SCHULZ1986A] 11. Koczet, P., Schulz, R. (1986): Three Faces of Comet Halley. Astronomy, November 1986, p. 44 [KOCZET&SCHULZ1986B] 12. Celnik, W.E. (1986): Hunting Halley's Comet. ESO Messenger 45, 6 [CELNIK1986C] 13. Celnik, W.E. (1986): Red-Image of Comet 1P/Halley. PULSAR 656, 247 [CELNIK1986D] 14. Celnik, W.E. (1986): Halley-Bochum: direction Am'Sud, PULSAR 657, 290 [CELNIK1986E] 15. Celnik, W.E., Schmidt-Kaler, Th. (1987): Structure and dynamics of plasma- tail observations of comet P/Halley 1986 and inferences on the structure and activity of the cometary nucleus. Astron. Astrophys. 187, 233 [CELNIK&SCHMIDTKALER1987] 16. Schulz, R. (1987): Die Dynamik der neutralen Zyan-Koma des Kometen P/Halley, Diplomarbeit, Ruhr-Universität Bochum [SCHULZ1987] 17. Celnik, W.E., Koczet, P., Schlosser, W., Schulz, R., Svejda, P., Weissbauer, K. (1988): Structure and dynamics of plasma tail condensations of comet P/Halley 1986. Astron. Astrophys. Suppl. 72, 89 [CELNIKETAL1988] 18. Schulz, R., Schlosser, W., Roessler, K. (1988): CN-Observations of Comet P/Halley and chemistry of possible parent molecules. Astron. Ges. Abstract Ser. No. 1, 7 [SCHULZETAL1988] 19. Schulz, R., Schlosser, W. (1989): CN-Shell structure and dynamics of the nucleus of comet P/Halley. Astron. Astrophys. 214, 375. Erratum in: Astron. Astrophys. 222, 367 [SCHULZ&SCHLOSSER1989A] 20. Schulz, R., Schlosser, W. (1989): Determination of the radial CN- Distribution in the Coma of Comet P/Halley by Image Processing Techniques. IAU-Coll. Comets in the Post Halley Era, p. 225 [SCHULZ&SCHLOSSER1989B] 21. Celnik, W.E., Schlosser, W., Schulz, R., Svejda, P. (1989): Color Image of Comet 1P/Halley. In: G.D. Roth (Ed.), Handbuch für Sternfreunde, Vol. 2, Springer Verlag, (Title) [CELNIKETAL1989] 22. Schulz, R., Schlosser, W. (1990): CN jets as progenitors of CN shells in the coma of Comet P/Halley. Proc. 24th ESLAB Symp., ESA SP-315, p. 121 [SCHULZ&SCHLOSSER1990] 23. Meisser, W. (1990): Lichtelektrische Messungen des Kometen P/Halley 1986, Diplomarbeit, Ruhr-Universität Bochum [MEISSER1990] 24. Schulz, R. (1990): ...und er taumelt doch! Sterne und Weltraum 5/1990, 300 [SCHULZ1990] 25. Schulz, R. (1991): Quantitative Strukturanalyse der Zyan-Koma des Kometen Halley. (Quantitative structural analysis of the cyan coma of comet Halley). Dissertation (thesis), Ruhr-Universität Bochum, Germany [SCHULZ1991A] 26. Schulz, R. (1991): Structural analysis of Comet Halley's CN coma by image processing techniques. Proc. 3rd ESO/ST-ECF Data Analysis Workshop, Hrsg.: D. Baade, P.J. Grosbol, Garching, p. 73 [SCHULZ1991B] 27. Schulz, R., Schlosser, W., Meisser, W., Koczet, P., Celnik, W.E. (1992): Spatial and temporal variations in the column density distribution of comet Halley's CN coma. Proc. Internat. Conf. on Asteroids, Comets, Meteors 1991, Flagstaff, AZ (USA), Eds.: E.W. Harris, E. Bowell, p. 537 [SCHULZETAL1992A] 28. Schulz, R., A'Hearn, M.F., Samarasinha, N.H. (1992): Simulation of CN jets and CN shells in comet P/Halley. Bull. Am. Astron. Soc., Vol. 24, 1004 [SCHULZETAL1992B] 29. Schlosser, W., Schulz, R., Klawuhn, L., Stüwe, J.A. (1992): The characteristic lifetime of the CN radical in comet P/Halley. Bull. Am. Astron. Soc. 24, 1025 [SCHULZETAL1992C] 30. Schulz, R. (1992): The connection between CN jets and CN shells in the coma of comet P/Halley. Icarus 96, 198 [SCHULZ1992] 31. Schulz, R. (1993): CN column density distribution in comet P/Halley. Astron. Astrophys. 268, 319 [SCHULZ1993] 32. Schulz, R., A'Hearn, M.F., Samarasinha, N.H. (1993): On the formation and evolution of gaseous structures in comet P/Halley. Icarus 103, 319 [SCHULZETAL1993] 33. Huang, B., Combi, M., Cochran, A., Fink, U., Schulz, R. (1993): Time- dependent model analysis of 8-days of CN spatial profiles in P/Halley. Bull. Am. Astron. Soc. 25, 1049 [HUANGETAL1993] 34. Voelzke, M.R. (1993): Analyse der Plasmakoma des Kometen P/Halley mittels Bildverarbeitung der Bochumer Photoplatten. (Analysis of the Plasma-Coma of Comet P/Halley by Image Processing Techniques of Bochum's Photoplates). Dissertation (thesis), Ruhr-Universität Bochum [VOELZKE1993] 35. Grothues, H.-G. (1993): Aktivität in Kometen. Sterne und Weltraum 32, 596+688 [GROTHUES1993] 36. Combi, M., Huang, B., Cochran, A., Fink, U., Schulz, R. (1994): Time- dependent analysis of 8 days of CN spatial profiles in comet P/Halley. Astrophys. J. 435, 870 [COMBIETAL1994] 37. Grothues, H.-G. (1994): Strukturen im Staubschweif von Komet P/Halley 1986 und ihr Zusammenhang mit der Aktivitaet des Kometenkernes. (Structures within the dust tail of comet P/Halley 1986 and the connection to the activity of the cometary nucleus). Dissertation (thesis), Ruhr-Universität Bochum, Germany [GROTHUES1994] 38. Schulz, R., A'Hearn, M.F. (1995): Shells in the C2 Coma of Comet P/Halley, Icarus 115, 191 [SCHULZ&AHEARN1995] 39. Grothues, H.-G. (1995): What do Streamers in the Dust Tail tell us about the Cometary Nucleus Astrophys. Space Sci. 229, 1 [GROTHUES1995] 40. Voelzke, M.R., Schlosser, W., Schmidt-Kaler, Th. (1995): Analise temporal da coma de CO+ no cometo P/Halley. Bol. Soc. Astr.Brasil 15, No. 1, 133 [VOELZKEETAL1995] 41. Voelzke, M.R. (1996): Analysis of the Plasma-Coma of Comet P/Halley by Image Processing Techniques of Bochum's Photoplates. PASP 108, p. 1063 [VOELZKE1996] 42. Voelzke, M.R., Matsura, O.T. (1996): Time analysis of the CO+ coma of comet P/Halley by image processing techniques. Rev. Mex. Astron. Astrofis., Ser. Conf., Vol. 4, p. 119 [VOELZKE&MATSURA1996] 43. Grothues, H.-G., Schmidt-Kaler, Th. (1996): The Dust Tail of Comet 1P/Halley after its Perihelion in 1986 and the Rotation of the Nucleus. Mon. Not. R. Astron. Soc. 282, 547 [GROTHUES&SCHMIDTKALER1996] 44. Dahm, Chr. (1996): Ermittlung von Staubgeschwindigkeiten in der Koma des Kometen P/Halley bei 420-750 nm mittels Bildfolgenanalyse. Diplomarbeit, Ruhr-Universität Bochum, Germany [DAHM1996] 45. Voelzke, M.R., Schlosser, W., Schmidt-Kaler, Th. (1997): Time Analysis of the CO+ Coma of Comet P/Halley by Image Processing Techniques. Astrophys. Space Sci. 250, Nr. 1, p. 35 [VOELZKEETAL1997] 46. Celnik, W.E., Koczet, P., Schlosser, W., Schulz, R., Svejda, P., Weissbauer, K. (1998): Images of Comet 1P/Halley. In: A. Kammerer / M. Kretlow (Hrsg.): Kometen beobachten, Verlag Sterne und Weltraum, München, p. 105 [CELNIKETAL1998] Acknowledgements We thank the Director General of the European Southern Observatory for the allowance to set up special equipment on ESO ground, and the ESO staff for valuable help during the observational run. Thanks are due to Dr. K. Jockers for lending us some optical filters during the observational campaign, and to Dr. J. Zender for helping us organizing and technically establishing the digital archive. The support of the observations by the Deutsche Forschungsgemeinschaft under grant Ce 21/1-1 is gratefully acknowledged. The ESA Research and Scientific Support Department has financed and technically supported the scanning procedures and made the digital archive available to the public. Figures Fig. 1: Example full-scale image of the galaxy M 83 with Hasselblad camera, f.l. 110 mm, and CO+ filter, exposed on April 2, 1986. M 83 is in the image centre. Fig. 2: Example full-scale image of M 83 with Flat-Field-Camera, f.l. 760 mm, and CO+ filter, exposed on March 14, 1986 Fig. 3: Example full-scale images of comet 1P/Halley with Hasselblad camera, f.l. 110 mm, and different filters: OG530 (a), blue-continuum filter (b), CO+ (c), CN (d), exposed on April 16, 1986. Fig. 4: Example full-scale images of comet 1P/Halley with Flat-Field-Camera, f.l. 760 mm, and different filters: OG530 (a), CO+ (b), CN (c), exposed on March 16, 1986 Fig. 5: The parallactic telescope mounting for photographic work Fig. 6: Four Hasselblad wide-angle-cameras, f.l. 110 mm, equipped with four different optical filters, for simultaneous exposures in different spectral bands. Fig. 7: Radiation beam within the Flat-Field-Camera used. Fig. 8: Spectral transmission of the Zeiss Planar 110 mm f/2 lens. Fig. 9: Example image of a spot series on 35-mm-film. Fig. 10: Example image for a spot series on 2 plates. Fig. 11: Example of a comet image series with the Flat-Field-Camera on April 16, 1986, exposure times 20 minutes, 6 minutes, 2 minutes, 30 seconds, 10 seconds, on Kodak 103a-E 35-mm-film, without any filter. Fig. 12: Spectral sensitivity of (a) 103a-F, (b) 103a-E and (c) Technical Pan 2415 (from KODAK data sheets) Fig. 13: Spectral transmission of optical filters used. The relative transmission in vertical direction is marked for each curve, horizontal direction indicates the wavelength, the temperature during transmission measurement is quoted. (a) CN filter for Hasselblad, temperature unknown, 1 horizontal tic-mark is 2.53 nm. (b) CN filter for Flat-Field-Camera, 12 °C, 1 horizontal tic-mark is 2.39 nm. (c) CO+ filter for Flat-Field-Camera, 12 °C, 1 horizontal tic-mark is 2.51 nm. (d) CO+ filter for Hasselblad, 12 °C, 1 horizontal tic-mark is 2.52 nm. (e) short-wave-passband filter for blue continuum, was combined with a Schott GG 375 long-wave-passband filter, 1 horizontal tic-mark is 12.5 nm, only the transmission curve of the short-wave- passband filter is shown, 25 °C. (f) H2O+ filter for Hasselblad, temperature unknown, transmission scale: top has to be changed to bottom, wavelength scale increasing to the left, wavelength marks are indicated. (g) CO2+ filter for Hasselblad, temperature unknown, wavelength marks are indicated. (h) GG 410 filter for Flat-Field-Camera, temperature unknown, wavelength scale is indicated. Fig. 14: The plates are stored upright within slots cut from wooden devices, and in a steel cupboard Fig. 15: The film strips are stored upright within filmholder sheets Fig. 16: Example image of Halley photographed through clouds on February 21, 1986, near the eastern horizon, using Hasselblad f.l. 110 mm f/2 and OG 530 filter. Fig. 17: Example image showing the comet in foreground of the Milky Way, exposure on April 4, 1986, using Hasselblad f.l. 110 mm f/2 and CO+ filter. Fig. 18: Example image showing moonlight incidence disturbing the image, exposure on April 1, 1986, using Hasselblad f.l. 110 mm f/2 and OG 530 filter. Fig. 19: Example images showing incidence of foreign light, left: exposure on April 9, 1986, using Hasselblad f.l.110 mm and CN filter, right: exposure on March 12, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and CN filter. Fig. 20: Example image showing electrostatic flashes on TP 2415 film, exposure on April 17, 1986, using the Flat-Field-Camera f.l. 760 mm f/4. Fig. 21: Example image showing voids within the emulsion, exposure on April 15, 1986, using Hasselblad f.l. 110mm f/2 and CO+ filter. Fig. 22: Example image showing irregular fog within the emulsion, exposure on March 3, 1986, using Hasselblad f.l. 110 mm f/2 and CO+ filter. Fig. 23: Example image showing optical coma produced by the f/2 lens, exposure on March 24, 1986, using Hasselblad f.l. 110 mm and broad-band blue-continuum filter, left: full-scale image, right: detail enlarged from the upper right corner. Fig. 24: Example full-scale image showing optical vignetting, exposure on March 23, 1986, using Hasselblad f.l. 110 mm f/2 and CN filter. Fig. 25: Example image showing bad focusing, exposure on March 12, 1986, using Hasselblad f.l. 110 mm f/2 and OG 530 filter. Fig. 26: Example full-scale image showing an interrupted exposition, exposure on March 30, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and CN filter. Fig. 27: Example full-scale image showing bad guiding, exposure on April 9, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and CN filter. Fig. 28: Example full-scale image showing scratches, exposure on March 14, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and CO+ filter. Fig. 29: Example full-scale image showing spots by chemicals, exposure on February 22, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and OG 530 filter. Fig. 30: Example full-scale images showing spots of humidity or fungus. Left: exposure of comet 1P/Halley on February 24, 1986, using Hasselblad f.l. 110 mm f/2 and CO+ filter. Right: exposure of M 83 on March 27, 1986, using the Flat-Field-Camera f.l. 760 mm f/4 and CO+ filter. Fig. 31: Example full-scale image with finger prints, exposure on February 28, 1986, using Hasselblad f.l. 110 mm f/2 and broad-band blue- continuum filter. Fig. 32: Example full-scale image on a broken glass plate, exposure on March 20, 1986, using Hasselblad f.l. 110 mm f/2 and CO+ filter. Fig. 33: The flatbed scanner "Epson perfection 3200 photo" opened, with plates on the scanning area. Fig. 34: The flatbed scanner "Epson perfection 3200 photo" opened, with film strips on the scanning area. Fig. 35: Example of an original scan of plates: resp. two image plates were scanned together with the sensitometer spot series valid for the day and distributed over two plates. Fig. 36: Example of an original scan of film strips: several film strips were scanned together with the sensitometer spot series valid for the day on one single film strip. Fig. 37: Example image of the scanner flat-field. Top: in original contrast showing pixel values between 0 (black) and 65535 (white). Bottom: in unrealistic high contrast showing pixel values between 53970 (black) and 65535 (white).