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24-524: The name "Bamberg" goes back to the builder of the telescope, Carl Bamberg (* 12. Juli 1847 in Kranichfeld ; † 4. Juni 1892 in Friedenau ), and the term "refractor" ( Latin re = 'back' and frangere = 'refract') means that the telescope is made exclusively with light-refracting optical lenses and does not use mirrors or zone plates . The 12- Zoll - telescope was built in 1889 in

48-608: A film identification system for 120 and 220 format roll film called Barcode System (with logo "|||B"). The barcode encoding the film format and length as well as the film speed and type is located on the sticker between the emulsion carrying film and the backing paper. This 13-bit barcode is optically scanned by newer medium format cameras like the Fujifilm GA645i Professional, GA645Wi Professional, GA645Zi Professional, GX645AF Professional, GX680III Professional and GX680IIIS Professional ,

72-445: A maximum number of resolvable line pairs N L {\displaystyle N_{L}} along the image circle diameter B {\displaystyle B} in the image plane of the telescope of: Thus, for the wavelength in the green, it follows: This results in a maximum spatial frequency of just under 48 line pairs per millimetre in the image plane, and for an image circle diameter of 21 millimetres in

96-830: A new electrically controlled tracking by the company 4H Jena-Engineering. In addition to the refractor in Rathenow , the great refractor in Potsdam and the great refractor of the Archenhold Observatory in Treptow , the Bamberg-Refraktor is still one of the large telescopes in the Berlin area. It is the oldest functioning large telescope with lenses in Europe. The Bamberg Refractor was designed according to

120-767: A new location was sought. In November 1961, the foundation stone was laid for the Wilhelm Foerster Observatory built with funds from the Deutsche Klassenlotterie Berlin on the Insulaner in Berlin-Schöneberg, which was piled up after the war as a mountain of rubble to a height of a good 78 metres. In 1962, Askania in Berlin-Mariendorf carried out a general overhaul of the telescope, and since

144-410: A small red window at the rear of the camera. A spool of roll film is usually loaded on one side of the camera and pulled across to an identical take up spool on the other side of the shutter as exposures are made. When the roll is fully exposed, the take up spool is removed for processing and the empty spool on which the film was originally wound is moved to the other side, becoming the take up spool for

168-463: Is 120 film , which is used in most medium format cameras and roll film magazines for large-format cameras. Until the 1950s, 120 roll film was, with the smaller 127 film , also used in the simplest of box cameras and other snapshot cameras. The use of roll film in consumer cameras was largely superseded by 135 and 126 cartridges, but 120 and 220 (double length) film are still commonly used in medium format cameras. In 1998, Fujifilm introduced

192-431: Is any type of spool-wound photographic film protected from white light exposure by a paper backing. The term originated in contrast to sheet film . Confusingly, roll film was originally often referred to as "cartridge" film because of its resemblance to a shotgun cartridge. The opaque backing paper allows roll film to be loaded in daylight. It is typically printed with frame number markings which can be viewed through

216-549: Is balanced in such a way that it can be moved by hand without motors. The telescope of the Bosscha Observatory in Indonesia, also called the Bamberg-Refraktor, has a focal length of seven metres, a diameter of 370 millimetres ( lens speed = 19) and was first commissioned in 1927 in Berlin. The comparatively large and thin lenses of this long-focal-length telescope cause an optically detectable deformation of

240-459: The Airy disc in the image plane at a wavelength λ {\displaystyle \lambda } of 550 nanometres in the green by the diffraction limit is: Thus, the optical resolution of the Bamberg-Refraktor, limited by diffraction and given as the smallest angle δ {\displaystyle \delta } between two stars still to be distinguished, is: This gives

264-411: The eyepiece , this results in a maximum spatial frequency of 1000 line pairs per image circle diameter. The light intensity is sufficient to observe objects up to more than 14th  apparent magnitude . Depending on the eyepiece used, the telescope is usually operated with magnifications of 70x to 700x. With telescope mount and balance weight, the instrument weighs four and a half tonnes. It

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288-671: The Bamberg-Refraktor, Adolf Voigt and Hans Giebler of the Berlin Lunar Observers Group made the roll film images for the Berlin Lunar Atlas from 1964 to 1969, which have since been made available as a digitisation . Today, the large refractor is mainly used for public demonstrations. In 1996 and 1997 the Bamberg refractor was overhauled by Gebhard Kühn at Zeiss in Jena, and in 2020, it was equipped with

312-714: The Berlin workshops of Carl Bamberg in Friedenauer Bundesallee in Berlin , was at the time the largest telescope in the Kingdom of Prussia and the second largest in the German Empire after the refractor at the Observatoire de Strasbourg . It was characterised by careful manufacture, a large focal length and modern control technology. An electric clock was used for the largely automatic tracking of

336-1055: The Düsseldorf Observatory, the Jena Observatory and the Urania Berlin Observatory. He is best known for the Bamberg-Refraktor , a large telescope in Berlin. In 1878 he set up a time ball station at Wilhelmshaven . After his death, his company became Askania-Werke AG, which continues to this day. His parents were Johann Christian Heinrich Bamberg from Kranichfeld and Johanna Dorothe Karoline, née Heintz, from Berka. He married Emma Caroline Roux (1847–1908), daughter of University of Jena fencing master Friedrich Wilhelm Roux , on 26 April 1874. They had two sons, Ernst Wilhelm Julius Bamberg (1875–1882) and Paul Adolf Bamberg (1876-1946). Roll film Roll film or rollfilm

360-568: The half-ruin of a former officers' mess by the two Berlin amateur astronomers Hans Rechlin and Hans Mühle and transferred to the Wilhelm-Foerster-Sternwarte Association in June 1953. The Bamberg-Refraktor was also used there for public demonstrations, but also for training astronomers. However, the light pollution from the nearby railway facilities at Südkreuz proved unfavourable for night sky observations, so

384-544: The lenses when the telescope changes position, due to their own weight. Carl Bamberg Johann Carl Wilhelm Anton Bamberg (born 12 July 1847 in Kranichfeld, died 4 June 1892 in Friedenau ) was a German engineer and entrepreneur. He began his career as an apprentice at Carl Zeiss . In 1871 he founded his own company, manufacturing cathetometers and planimeters . He manufactured equatorial telescopes for

408-491: The melt. The two lenses that are not cemented together have the following parameters: From the aperture width D = 320  mm {\displaystyle D=320{\text{ mm}}} and the focal length results in a lens speed of just under 16 and an aperture ratio of a good 1/16 respectively: The image-side angular aperture is: The spherical aberration is not corrected. The diameter d B {\displaystyle d_{B}} of

432-543: The next roll of film. In 1881 a farmer in Cambria, Wisconsin, Peter Houston, invented the first roll film camera. His younger brother David, filed the patents for various components of Peter's camera. David Henderson Houston (born June 14, 1841; died May 6, 1906), originally from Cambria, Wisconsin, patented the first holders for flexible roll film. Houston moved to Hunter in Dakota Territory in 1880. He

456-637: The opening of the Wilhelm Foerster Observatory on 30 January 1963, the refractor in the largest dome of the public observatory has been the most important and frequently used instrument for demonstrations by the society. The movable dome with a diameter of eleven metres dates from 1905. It was no longer needed at the Berlin Zeiss-Ikon factories in Berlin-Friedenau and was given to the observatory. Using

480-648: The principle of the Kepler telescope with an optical corrected lens system constructed with spherically ground lenses of flint and crown glass . By combining the two glass types with different dispersion , the lens is achromatic , so that the blue and red light components have almost the same back focal length , which is, however, slightly larger than the cut width in the green. The glasses are ordinary silicate glasses from Schott , which were, however, processed very elaborately and with particular care so that they could solidify stress-free and optically pure from

504-530: The telescope according to the hour angle of the object to be observed. The lenses were made of high-quality glass from the Glastechnisches Laboratorium Schott & Genossen in Jena. The total cost was 50,000 Mark , which corresponded to 250 kilograms of silver ( Note: This amount of silver corresponds to a good 8,000  fine ounces with a market value (as of 2018/2019) of a good 100,000 euros). Initially, it

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528-511: Was issued an 1881 patent for a roll film holder which he licensed to George Eastman (it was used in Eastman's Kodak 1888 box camera ). Houston sold the patent (and an 1886 revision ) outright to Eastman for $ 5000 in 1889. Houston continued developing the camera, creating 21 patents for cameras or camera parts between 1881 and 1902. In 1912 his estate transferred the remainder of his patents to Eastman. The most popular roll film format

552-622: Was not only available for research purposes, but primarily for the public in the observatory of the Urania on Invalidenstraße in Berlin, which was equipped with an electrically operated dome. Among the first astronomers working there were Friedrich Simon Archenhold and the co-founder of the Urania Wilhelm Foerster . With the refractor, the astronomer Gustav Witt discovered the asteroids (422) Berolina and (433) Eros in 1896 and 1898. The polar explorer Alfred Wegener , who

576-819: Was trained as an astronomer, also used the Bamberg refractor in the Urania. During the Second World War , the building was severely damaged, but the glass lenses remained undamaged. The telescope was salvaged in 1951 and was repaired by the Askania workhouses in Berlin-Mariendorf . In 1955, it was set up as the largest operable telescope in Berlin on the grounds of the observatory of the Wilhelm Foerster Institute in General-Pape-Straße in Berlin, which had been built up since 1947 in

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