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Plate Archive and Plate Scanner

Schmidt Archive
Archive of Spectra
Scanner


The Plate Archive of the Schmidt Telescope

The plate archive contains 9213 plates taken with the Tautenburg Schmidt telescope .

A computer-readable catalogue of the plates includes the following data : 

PLNR plate number
ALPHA right ascension of the plate center
DELTA declination of the plate center
DATE date of the beginning of the exposure (CET)
BEGIN time of the beginning of the exposure (CET) 
EXPT exposure time
COL information about the emulsion-filter combination
W with or without wedge
REMARK remarks like objective prism plate, guided to minor planet
SPO special objects, in most cases comets
PLACE place of storing (loaning), monthly actualised 
S "*", if the plate is scanned

                
The catalogue (schmicat.sdf) with a short description (schmidoc.txt) is available via anonymous ftp.

Also available via ftp is a list (scanned.sdf) of the plates scanned with the Tautenburg Plate Scanner and stored on CD-ROM (AUG 2007: 4228 plates digitised).

In this list, the data PLNR, ALPHA, DELTA, DATE, COL, W are the same as mentioned above. For some plates information about the limiting magnitude (LMAG) and the number of objects (NOBJ) detected on the plate is given as well.

An overview about the distribution of the observed fields on the sky you can get in this picture. You can also download it via anonymous ftp as a compressed fits-file (skytbg.fits.gz). Viewing with "saoimage" and moving the cursor inside the picture you will get the coordinates with an accuracy of 0.1° and as z-value the number of plates taken at the given position.

Online search
 for coordinates in the plate catalogue.

Last update: Aug 15, 2007

For more information, please contact Helmut Meusinger (<meus@tls-tautenburg.de> ).


The Plate Archive of the Tautenburg Spectrographs

Over 5000 photographic spectra were taken with the Coudé- or Cassegrain- spectrographs. A catalogue of these spectra (speccat.sdf) is available via anonymous ftp.

Online search for objects observed with these spectrographs.

Last update: March 28, 2000

For more information, please contact Holger Lehmann (<lehm@tls-tautenburg.de> ). 


The Plate Scanner

The Tautenburg Plate Scanner TPS is an advanced photographic plate measuring machine operated at the Thüringer Landessternwarte Tautenburg. The main components of the TPS comprise (1.) an x-y movable plate carriage, (2.) a diffuse illumination screen below, and (3.) a direct CCD imaging system above the plate carriage. All components are mounted on an air-bearing table. The TPS digitises plates by moving the plate through the optical path of the stationary imaging system. A strip of the illuminated plate is projected onto a CCD line detector by a telecentric mapping lens system.

Technical data

Plate dimension   max. 300mm x 300mm
  6000 x 1 Pixel CCD line
  (5400 pixel for plate digitisation,
  600 pixel for reference light monitoring), 
  telecentric mapping lens system,
  60mm linear field diameter 
  (in object and image plane),
  0.1 numerical aperture,
  30 µm focal depth
Scanning resolution 10 µm (2540 dpi) = CCD pixel size
Number of grey levels 4096, optionally 256
ADC amplification linear
Peak/digitisation noise >1000 
Dynamic range >3 photographic densities
CCD integration time 3ms...260ms adjustable
Max. scanning width 54mm (5400 pixel = free CCD width)
Max. scanning length 300mm (30000 pixel = max. travel length
Table encoder 300mm Heidenhain linear glass encoder, 
  2 µm grid, 100x interpolation,
  0.5 µm absolute accuracy over 300 mm
Table repeatability 0.4 µm
Light source 0...150 W adjustable Tungsten Halogen, 
  fibre optics transmission,
  stabilised via reference light beam 
Photometric stability better than 0.1% over 24 hours
Scanning speed typically 8 mm/min
Operating environment DOS-PC Pentium 100MHz, 64 MB RAM
Data storage 2 x 2 GB hard disk, 
  CD-writer, DAT-streamer
Output data format FITS (16 bit or 8 bit integer) 

A 24cm x 24cm plate is typically digitised within about 2.5 hours 10 µm resolution, resulting in 1.2 GB of pixel data. Final data processing is done off-line.

Scientific projects with digitised Schmidt plates

Last update: November 03, 2003

For more information, please contact Helmut Meusinger (<meus@tls-tautenburg.de> ).