Handbook of Star Forming Regions Vol. I Astronomical Society of the Pacific, 2008 Bo Reipurth, ed. Star Forming Regions along the Milky Way: A Panoramic View Axel Mellinger Institute for Physics and Astronomy, University of Potsdam Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany Present address: Department of Physics, Central Michigan University, Mount Pleasant, MI 48859, USA Abstract. The location of the star forming regions covered in this book is shown superimposed on a panoramic image of the Milky Way. Since ancient times, astronomers have sought to draw maps of the sky, similar to their cartographer colleagues’ drive to produce ever more accurate maps of the Earth. However, it was not until the invention of photography that faint, large-scale structures of nebulae and dust lanes could be faithfully reproduced. Since the late 19th cen- tury, several wide-angle photographic surveys of the sky have been completed, such as E. E. Barnard’s Atlas of Selected Regions of the Milky Way (Barnard et al. 1927), the Palomar Observatory Sky Survey of the northern sky and subsequently the equivalent ESO/SERC atlas of the southern sky, and more recently the Sloan Digital Sky Survey. World maps showing the entire globe projected onto a single sheet of paper have become commonplace since the Renaissance. However, photographic all-sky images were much harder to produce. A key problem in the pre-digital era was the change of projection from the type provided by the camera system (typically, a gnomonic projec- tion, see Calabretta & Greisen (2002), with additional pincushion or barrel distortions) to the desired map projection (such as Aitoff, Mercator or equidistant azimuthal). The famous 1955 Lund Observatory all-sky panorama image (Lundmark et al. 1955) was hand-crafted with paintbrushs and spray paint. Interestingly, non-artistic, seamless all- sky maps at radio wavelengths appeared before their optical counterparts. By the mid 1990s, however, common office personal computers had sufficient computational speed and memory to make digital image processing accessible even to amateur astronomers. At the same time, 35 mm color negative films reached their peak performance in astrophotography, exhibiting low reciprocity failure and finer grain than their predecessors. Taking advantage of these factors, the author embarked on a project to create an all-sky color image (Mellinger & Hoffmann 2005). The imaging equipment consisted of a Minolta SRT-101 camera with a 2.8/28 mm Minolta MD lens (stopped down to f/4), mounted on either a Vixen Super Polaris or a Losmandy G-8 German equatorial mount. Between the years 1997 and 2000, a total of 51 images were recorded on Kodak PJM and PJ-400 film from various sites in Africa, Europe and North America, with the bulk of the northern sky photographed from California’s Eastern Sierra, while the southern hemisphere images were taken at Cederberg Observatory (Forder 1994) and other locations in South Africa’s Western Cape Province. Each frame was exposed for 45 min. The negatives were digitized with a Polaroid Sprintscan 35 Plus scanner. In each image, several hundred reference stars were selected. Using custom software and posi- 1
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Star Forming Regions along the Milky Way: A Panoramic Vie · E. E. Barnard’s Atlas of Selected Regions of the Milky Way (Barnard et al. 1927), the Palomar Observatory Sky Survey
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Handbook of Star Forming Regions Vol. IAstronomical Society of the Pacific, 2008Bo Reipurth, ed.
Star Forming Regions along the Milky Way:A Panoramic View
Axel Mellinger
Institute for Physics and Astronomy, University of PotsdamKarl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
Present address: Department of Physics, Central Michigan University, MountPleasant, MI 48859, USA
Abstract. The location of the star forming regions covered in this bookis shownsuperimposed on a panoramic image of the Milky Way.
Since ancient times, astronomers have sought to draw maps ofthe sky, similar totheir cartographer colleagues’ drive to produce ever more accurate maps of the Earth.However, it was not until the invention of photography that faint, large-scale structuresof nebulae and dust lanes could be faithfully reproduced. Since the late 19th cen-tury, several wide-angle photographic surveys of the sky have been completed, such asE. E. Barnard’sAtlas of Selected Regions of the Milky Way(Barnard et al. 1927), thePalomar Observatory Sky Survey of the northern sky and subsequently the equivalentESO/SERC atlas of the southern sky, and more recently the Sloan Digital Sky Survey.
World maps showing the entire globe projected onto a single sheet of paper havebecome commonplace since the Renaissance. However, photographic all-sky imageswere much harder to produce. A key problem in the pre-digitalera was the change ofprojection from the type provided by the camera system (typically, a gnomonic projec-tion, see Calabretta & Greisen (2002), with additional pincushion or barrel distortions)to the desired map projection (such as Aitoff, Mercator or equidistant azimuthal). Thefamous 1955 Lund Observatory all-sky panorama image (Lundmark et al. 1955) washand-crafted with paintbrushs and spray paint. Interestingly, non-artistic, seamless all-sky maps at radio wavelengths appeared before their opticalcounterparts.
By the mid 1990s, however, common office personal computers had sufficientcomputational speed and memory to make digital image processing accessible even toamateur astronomers. At the same time, 35 mm color negative films reached their peakperformance in astrophotography, exhibiting low reciprocity failure and finer grain thantheir predecessors. Taking advantage of these factors, theauthor embarked on a projectto create an all-sky color image (Mellinger & Hoffmann 2005). The imaging equipmentconsisted of a Minolta SRT-101 camera with a 2.8/28 mm Minolta MD lens (stoppeddown tof/4), mounted on either a VixenSuper Polarisor a Losmandy G-8 Germanequatorial mount. Between the years 1997 and 2000, a total of51 images were recordedon Kodak PJM and PJ-400 film from various sites in Africa, Europe and North America,with the bulk of the northern sky photographed from California’s Eastern Sierra, whilethe southern hemisphere images were taken at Cederberg Observatory (Forder 1994)and other locations in South Africa’s Western Cape Province. Each frame was exposedfor 45 min.
The negatives were digitized with a Polaroid Sprintscan 35 Plus scanner. In eachimage, several hundred reference stars were selected. Using custom software and posi-
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tion data from the PPM catalog (Roeser & Bastian 1991), an astrometric solution wascalculated, and the image was transformed to an equidistantcylindrical projection inGalactic coordinates. The final assembly into a14400 × 7200 pixel image was per-formed with open-source image processing software.
Panels 1-6 each show a 45◦-wide strip of the all-sky image, centered on the Galac-tic equator. The Galactic bulge is prominently visible, as is the “Great Rift” of inter-stellar dust. Selected star forming regions discussed in this book are listed in Table 1.
Acknowledgments. The author gratefully acknowledges the hospitality of the am-ateur astronomers at Cederberg Observatory, Western Cape Province, South Africa,where many of the southern sky images were taken. The G-8 mount was a loan fromDebbie Dyke (Eastbay Astronomical Society, Oakland, CA).
References
Barnard, E. E., Frost, E. B., & Calvert, M. R. 1927, A photographic atlas of selected regions ofthe Milky Way (Carnegie Institution of Washington)
Calabretta, M. R. & Greisen, E. W. 2002, A&A, 395, 1077Forder, C. 1994, Monthly Notes of the Astronomical Society of South Africa, 53, 32Lundmark, K. et al. 1955, The Lund Panorama of the Milky Way,
URL: http://www.astro.lu.se/Resources/Vintergatan/Mellinger, A. & Hoffmann, S. M. 2005, The New Atlas of the Stars (Firefly Books)Roeser, S. & Bastian, U. 1991, PPM Star Catalogue North. Positions and proper motions of
181.731 stars north of−2.5 degrees declination for equinox and epoch J2000.0 (Heidel-berg: Spektrum Akademischer Verlag)
Panoramic Milky Way Image 3
Table 1.: List of Star Forming Regions plotted in Panels 1-6.
Object Galactic Equatorial (2000.0) Panel #l b RA Dec