1. Oswald Lohse Historical Photographic Wide-Field Survey:Camera Replica Milcho K. Tsvetkov 1, Gotthard Richter 2, Klaus Staubermann 3, Svetlin Fotev 4, Ivan Parov 5 Petra Boehm 2, Katya Tsvetkova 1 1) Institute of Astronomy, Bulgarian Academy of Sciences 2) Astrophysicalishes Insitute Potsdam, Germany 3) Utrecht University, University Museum, The Netherlands 4) Space Research Institute, Bulgarian Academy of Sciences 5) Department of Astronomy,Sofia University, Bulgaria July, 2004

2. 1.Introduction WFPDB 2. Lohse Plate Archives re-discovery 3. Including of the Plate Archive in WFPDB 4. Lohse Plate Digitization 5. Lohse Photographic Camera 6. Replica Sources and Publications Drawings Preparing of the Replica Test at the Sofia Observatory Plates Future Plans

3. Introduction Wide-Filed Plate Database WFPDB Project Goals –Developed as a project of the IAU WG WFI, started in 1991 at the IAU GA, WG WFI Chairman Richard West and WGSS IAU Commission 9. Supported by: Bulgarian NSF 1993-2001: F-311, 340, 650 I-529, 1103, Alexander von Humboldt Foundation, Center for Informatics, Muenster University, German Research Council (DFG), COST A283. Main Directions: –Catalog of WFPA: 345, 2.2x10 6 plates –Plate logs transformation - 700 000 plates –Search in WFPDB: http://www.skyarchive.org/search –Plate digitization: Epson 1640XL, PDS1010plus

4. Introduction Wide-Filed Plate Database Website:http://www.skyarchive.org

5. More WFPDB Descriptions: FOR MORE INFO... Website:http://www.skyarchive.org

6. Potsdam plate archives: WFPDB incorporation: The Astrophysical Institute Potsdam wide-field plate collection consists of 12 plate archives obtained in the period 1879 - 1970 (see Catalogue of Wide-Field Plate Archives, version 5.0, March 2004, http://www.skyarchive.org) with more than 10 000 plates and films stored not only in Potsdam but in Leiden and Sonneberg, too. The plates contain valuable astronomical information easily to be retrieved. The Potsdam wide-field plate collection reflects also the history and development of the Potsdam Observatory The accumulated wide-field photographic observations in the Astrophysical Institute Potsdam (AIP) have well known contributions to astronomy, but also to the development of photography itself. Such are the contributions of many observers from Potsdam, e.g. O. Lohse (since the foundation of the observatory), J. Scheiner (the end of 19th century), J. Hartmann (the beginning of 20th century), E. Hertzsprung and K. Schwarzschild (the 10s of 20th century), G. Eberhard (the 20s - 30s of 20th century). Another aspect of this development is that practically the Potsdam Observatory was the base for testing of new astronomical emulsions, beginning with the dry photographic plates of Schleussner (fabric in Frankfurt) to AGFA Enterprise up to 1960 and ORWO after 1960. The process of archiving of the wide-field photographic observations comprises such steps as making of an inventory of the plate collection, preparation of computer- readable versions of the plate catalogues, plate digitization and providing of good storage with suitable temperature, humidity free conditions and easy access to the plates and to the plate digitized information...

7. Potsdam plate archives: WFPDB incorporation:..

8. The Lohse Plate Archives The LOHSE archives contain observations since 1879. According to the found Lohse's logbook 217 plates are obtained with the refractor with diameter 30 cm, focal length 5.4 m, and scale 38"/mm. The manufacturer of the optics was H. Schroeder and for the mechanics - A. Repsold. This refractor was called "the Great Refractor" in the period 1879-1899 (after 1899 the name "Great Refractor" was ascribed to the new 80 cm refractor, then put in operation). Since 1888 Lohse sometimes mounted on the refractor two heliographic objectives with a diameter 0.13 cm (the first one with focal length 2.10 m, scale 98 "/mm, and the second one with focal length 1.36 m, scale 152 "/mm, and field size 5 , Tsvetkov et al. 1999. Astron. Nachr., 320). Wilhelm Oswald Lohse (1845­1915)

9. The Lohse Plate Archives: Rediscovery The AIP Great Refractor Dome of the Great Refractor

10. The Lohse Plate Archives: Rediscovery The Lohse plates were re-discovered in 1998 in a small room on the 2 nd floor of the dome of the Great refractor in Telegrafenberg. - 6 boxes, plate with size of 9x12 cm The logbooks were accompanied with two blocknotes. At present they are stored under special conditions at the AIP library

11. The Lohse Plate Archives: Analysis 67 plates of the archives, taken with the greatest instrument of Potsdam in the period March 1885 ­ February 1889. from 217 plates, listed in his logbook, the first 148 from 1879 to 1885 are not found. One Lohse’s focus plate

12. The Lohse Plate Archives: Analysis Number of the plates vs. fields observed

13. The Lohse Plate Archives: Digitization 10 of the Lohse's plates have been chosen for digitalization with the PDS 2020 GM + microdensitometer of Muenster University in July 1998. The standard square diaphragm of 10 microns and a step size of 10 microns was used. Table 4 summarizes the scanning parameters and results. The measurements of 12 stars in B light from the photometric sequence of Andrews (1970) in Orion nebula (M42) show an average photographic photometry deviation of oe = 0:13 m (Fig. 4). In Fig. 4. and Fig. 5. the pictures of the stellar cluster h Persei (NGC 884) and Orion nebula (M42/M43) processed from the original Lohse's plate scans (LS 171, LS 213) with MIDAS are shown. LS. No. 213, M42

14. The Lohse Plate Archives: Digitization h PerseiM42-43, ORION

15. The Lohse Photographic camera: sources and publication The Lohse Photographic camera: sources and publication Publications: First professional photographic camera in the world Potsdam Observatory library Konkoly Observatory library Necessary better copies with details!

16. The Lohse Photographic camera pictures (cont.)

17. Drawing The Lohse Photographic camera Drawing The Lohse Photographic camera Svetlin Fotev, © SSADC, Eng. Svetlin Fotev

18. Drawing The Lohse Photographic camera Drawing The Lohse Photographic camera Svetlin Fotev, © SSADC

19. The Lohse Photographic camera Replica

20. Eng. Ivan Parov

21. The Lohse Photographic camera Replica : Test at the Grubb refractor of the Sofa University Observatory Searching a suitable telescope at the Balkan observatories to attach and test the replica. Sites tested: Belgrade, Bucharest, Konkoly, Sombathely, Sofia. Result: the best place for the test is the Sofia University Observatory with the 18 cm refractor (100 years old). The Uni-Sofia Observatory 18 cm Grubb Refractor

22. The Lohse Photographic Camera Replica : Test at the Grubb refractor of the Sofa University Observatory Dome of the Grubb Refractor

23. The Lohse Photographic Camera Replica : Test at the Grub refractor of the Sofa University Observatory

24. The Lohse Photographic camera Plates used Lohse used mainly the Dr. Schleussner plates with size of 9x12 cm.

25. The Lohse Photographic Camera Plate Used Preparing the plates according to the Gaedike technology from 19 century and used them to repeat the Lohse observations. The plates were prepared by Prof. Tsveta Petrova from the Central Laboratory for Optical Recording of the Information at the Bulgarian Academy of Sciences.

26. The Lohse Photographic Camera Prof. Tsveta Petrova CLOSOI, BAS Photolaboratory at the Uni-Sofia Observatory The Petrova’s samples of the Geadike type emulsion plates

27. The Lohse Photographic Camera: Future Plans Preparing a copy from the replica for AIP (grant needed) Repeating the Lohse observations Incorporation the Lohse plate scans in the WFPDB

28. Acknowledgements The Lohse Camera Replica was realized with the grant provided by Dr. Klaus Staubermann and the enthusiasm of the staff of Sofia Sky Archive Data Center and Sofia University Observatory. We are thankful to Prof. G. Ivanov providing us with the Grubb telescope of the Sofia University Observatory. In particular the incorporation of Lohse photographic observations was supported by the DFG/BAS grant BUL436/1999

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