This is the Web Site of the
IAU Task Force for the Preservation and Digitization of Photographic Plates (PDPP)
The Task Force is attached to IAU Commission 5,
Astronomical D

Please join PDPP and help rescue an important trove of scientific data that is also part of our astronomical heritage.
Contact Dr. Elizabeth Griffin, PDPP Chair, for more information.

Issues of SCAN-IT, the Newsletter of the PDPP Task Force, are downloadable as
uncompressed or WinZip-compressed files:

SCAN-IT #1 (2002) WinZip PDF On-line PDF    
SCAN-IT #2 (2004) WinZip PDF On-line PDF WinZip PS  
SCAN-IT #3 (2005) WinZip PDF On-line PDF WinZip PS  
SCAN-IT #4 (2006) WinZip PDF On-line PDF WinZip PS On-line PS
SCAN-IT #5 (2009) WinZip PDF On-line PDF WinZip PS On-line PS

SCAN-IT No. 6 was published on 2013 April 15.    It can be accessed at The PDPP SCAN-IT Library.
All previous issues of SCAN-IT can also be accessed there and from here.

Construction of a new home for the PDPP web-site is underway.
Please contact Elizabeth Griffin with any questions or suggestions regarding the new web site.

The SCAN-IT Editorials and Reports by our redoubtable Chair and SCAN-IT Editor,
Dr. Elizabeth Griffin can be read on-line:

Editorial in SCAN-IT I (2002)         Editorial in SCAN-IT II (2004)     View from the Chair in SCAN-IT III (2005)
Message from the Chair in SCAN-IT IV (2006)                  Editorial in SCAN-IT V (2009)

Submission of contributions to SCAN-IT can be made at any time to
Dr. Elizabeth Griffin.

Links List:
Additions to the following Links List of related web sites are always welcome!
Please contact
Thom Gandet to submit or update your link information.

IAU Commission 5: The IAU site for IAU Commission 5, Documentation and Astronomical Data.  The PDPP Task Force is attached to this IAU Commission.  The members of this Commission and their contact information is listed on this site. Commission 5 Working Groups whose charters are intimately tied into PDPP-related issues can be found there too: the Working Group on Astronomical Data, and the Working Group on Virtual Observatories, which is located at the International Virtual Observatories Alliance.

PARI: The center for digitizing North American plates and for their long-term archival storage is located at the Pisgah Astronomical Research Institute, in North Carolina USA.  PARI is a not-for-profit public foundation dedicated to providing research and educational access to radio and optical astronomy for a broad cross-section of users. PARI provides space, infrastructure, and Internet access.  The goal is to make the archive a resource that can be harnessed by present and future generations of astronomers.

Yerkes Observatory: Yerkes Observatory houses a collection of over 170,000 astronomical photographic plates. Almost all were taken in the twentieth century. Roughly 45% are direct plates, 45% slit spectra and 10% solar images, spectra or spectroheliograms. The majority of the plates were taken using the observatory's 40-inch refractor, the former 24-inch reflector and the wide-field photographic telescope. There are smaller collections taken with other Yerkes telescopes as well as with instruments at the McDonald, Dearborn, Perkins and the University of Illinois Observatories. Of particular interest are the deep photographs taken by E. E. Barnard 1900-1923. No complete inventory of the plate collection yet exists, but some information about the holdings can be found by clicking here.

Spectroscopic Virtual Observatory: The SVO will create a database of archival photographic spectra, most of which have never been digitized before.  The database and its associated operations will constitute the Spectroscopic Virtual Observatory.  The World Spectra Heritage Project is a related effort to gather together and scan spectra, from all over the world, for inclusion in the SVO database and to make the resulting data readily and easily available, much as are other data sets (such as, e.g., IRAS).

Maria Mitchell Observatory: The MMO 's collection of over 8,000 plates taken over the last century with the 7.5-inch Cooke/Clark camera was completely digitized in 2001-2002 using a high-performance commercial scanner.  In September of 2011, the plate collection was relocated to PARI.  The collection is especially rich for large (~10 degrees) regions in Scutum, Sagittarius and Cygnus.  Two versions of each scanned plate are available on individual CD's: a low resolution, 840 dpi, and a high resolution, 2500 dpi.   Copies of the CDs may be requested from Dr. Vladimir Strelnitzky, Director, Maria Mitchell Observatory.   Since its move to PARI in 2011, the catalog of plates is being edited and is presently off-line.

Digitized First Byurakan Survey The objective prism plates of the First Byurakan (Markarian) Survey have been scanned and the spectra automatically extracted.  Sections of the plates (FITS format) and the extracted spectra (ASCII) can be freely downloaded from a dedicated web page hosted at University La Sapienza.   Approximate B and R magnitudes are also available, computed from spectra integration,  linked to the USNO-A2 zero points. This project is a collaboration between Byurakan Observatory (Armenia), University La Sapienza (Roma, Italy) and Cornell University (USA).

Mt. Wilson Solar TowerMt. Wilson Solar Photographic Archive Digitization ProjectThis archive contains over 150,000 images of the sun acquired over more than 100 years.  The glass and acetate negatives are stored and maintained at the Pasadena, California, offices of the Observatories of the Carnegie Institution of Washington.  Steps are being taken as part of the project to improve the storage and preservation of the plates studied.   The Ca II K-line sequence is finished and available as of March 2006 and placed in files available here.


Standard Stars Newsletter: The Standard Star Newsletter is the publication of the Standard Stars Working Group, sponsored by Commissions 25, 29, 30, and 45 of the International Astronomical Union.  Its purpose is to keep astronomers in touch with all aspects of stellar standards used in photometry, spectroscopy, polarization, elemental abundance determinations, fundamental stellar parameters, and radial velocities.

30-inch Thaw Refractor Allegheny Observatory Parallax Project: The Allegheny Observatory of the University of Pittsburgh has, at present, no plans to digitize their large collection of parallax plates and spectra.  However, in cooperation with the The Digital Research Library (DRL) at the University of Pittsburgh, the Observatory has made The Publications of the Allegheny Observatory available online for searching.  The volumes can be searched for parallax by many star identifiers,  parallax value and other parameters.    Note: Similar data for spectra are not available on-line.   For more information please read About the Parallax Project.

Lizard Hollow Observatory proudly hosts the PDPP web site.

LHO Main Page

This web site was last updated on Wednesday, March 28, 2012.