Transcript La digitalizzazione degli archivi fotografici degli

The Italian and Vatican experience to
digitize the Astronomical Photographic
Archives
Cesare Barbieri1
([email protected])
Carlo Blanco3, Beatrice Bucciarelli4, Andrea Di Paola5, Luciano Lanteri4, Gian
Luca Li Causi5, Ettore Marilli3, Piero Massimino3, Stefano Mottola7, Roberto
Nesci6, Alessandro Omizzolo2, Fernando Pedichini5, Francesca Rampazzi1,
Corinne Rossi6, Ruggero Stagni1, Milcho Tsvetkov8, Roberto Viotti6
1Department
of Astronomy, University of Padova
2Specola Vaticana, Castelgandolfo
3INAF and University of Catania
4INAF Torino
5INAF Roma
6Department of Astronomy, University of Roma I
7 DLR Berlin, Germany
8Bulgarian Academy of Sciences, Sofia, Bulgary
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Introduction
Highly valuable information is stored in the photographic archives of
many Italian Observatories and in the Specola Vaticana. Several plates date back
to the end of the XIX Century. A proper digitization of this veritable treasury is
therefore of paramount importance, both for its preservation and for the fuller
exploitation of its scientific content.
Among the many scientific objectives of the digitization, we have
already undertaken the following tasks:
· time history of variable stars in the Milky Way and in external galaxies, of
AGNs and QSOs,
· spectral classification over wide fields
Some examples of achieved results will be presented in the following slides.
Other possible scientific programs will be:
· inventory of novae and supernovae in external galaxies,
· search for past transits of asteroids and comets, for a better reconstruction of
their orbital and physical evolution,
. Fundamental catalogues, discovery and inventory of high proper motion stars.
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The Photographic Archives Census - 1
Table 1 gives the total inventory of the useful plates in the participating Italian
Observatories:
Type
Number of Plates
Dates
Images
57500
1897-1998
Spectra
26100
1951-1994
Objective Prism
3100
1958-1998
While the Asiago Observatory archive was always kept in a well ordered manner,
the others have been fully reconditioned in the course of our project.
Lacking (unfortunately) in the present collaboration are two large Italian archives:
1) Campo Imperatore, which is scattered among the different observers.
2) Bologna-Loiano (including Horn's d'Arturo with the segmented mirror), which is
fortunately well ordered and kept.
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The Photographic Archives Census - 2
Table 2 gives the content of the Specola Vaticana archive, with plates coming
from the astrograph in its historical locations and from the Schmidt telescope in
Castelgandolfo.
Type
Number of Plates
Dates
Images
8500
1894-1986
Objective Prism
1326
1957-1986
Polarimeter
30
1957-1986
The Vatican archive is well preserved and ordered from the very first plate. For
every plate of the Carte du Ciel and of the Astrographic Catalogue there is a
detailed description of the characteristics, the plate constants to do astrometry, and
information concerning exposure time and weather conditions.
The digitization of the Schmidt logbooks is in progress by the Bulgarian
Academy of Sciences in Sofia.
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The hardware - 1
A typical working area.
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Several
commercial
scanners (produced by
Epson)
with
retroillumination, resolutions
of 1600x3200 dpi, format
A3 or A4, output at 14 or
16 bits, have been bought
for Asiago, Padova,
Catania,
Rome
and
Castelgandolfo.
The same scanners are
used by DLR in Berlin
and by several other
European institutes. The
scanners are connected
via USB2 or FireWire to
dedicated PCs.
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The hardware - 2
For imaging plates, Schmidt objective
prism material and low resolution
spectra (e.g. spectra taken with image
intensifiers), useful work can still be
done with the available equipment, as
shown by the adjacent figure.
However, for the fine grained
spectroscopic plates of the Asiago
122-cm spectrograph and for the
images on the S40/50 films, a higher
resolution (4800x9600 dpi), smaller
format scanner has been recently
installed in Padova.
Spectral types of 10th mag stars, from a
digitized objective prism plate taken in 1972
with the Campo Imperatore Schmidt.
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The acquisition software
Programs that greatly enhance the ease of data acquisition, working in the
Windows operating system and providing as output a positive or negative FITS
image (including the header) that can be directly analyzed with IRAF, MIDAS or
IDL, were initially written by S. Mottola (DLR), and implemented on all our
machines.
A. Di Paola (INAF Rome Observatory) has written another routine that
automatically analyses the header and generates the .jpg previews from the FITS
files.
Typical digitization time for a S67 plate of 20x20cm is 7 minutes, the overall
time raises to approximately 30 min per plate including inspection, handling and
cleaning.
Typical dimensions of the digitized plates at 1600 dpi range from 260 MB for
20x20 cm Schmidt plates to 70 MB for the 9x12 cm plates of the Asiago 122 cm
telescope.
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AstroPlates
At Catania
Observatory, another
tool (AstroPlates) has
been developed by P.
Massimino in Visual
Basic 6 for every 16bit Windows ambient.
AstroPlates requires
IDL 5.4 or later
versions.
It generates contemporarily FITS and jpeg files (with a selectable compression
factor), handles headers, images and catalogs.
An example is shown in the figure. A Beta release is available to interested users.
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The CCD photometric program
The overall national program comprises as crucial element the acquisition
of BVRI sequences in selected fields, by means of the CCD camera of the Campo
Imperatore Schmidt telescope, which covers a field of approximately 1x1 sq. deg.
Left: the CCD
frames acquired
in the M42 field.
See later for more
photometric details.
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The Asiago telescopes
Left: the 122 cm, which operated both at the Newton and Cass focus.
Right: the 182cm and the S67/92 cm at Cima Ekar, some 4km away; until 1991
the S67/92 was located next to the 122cm telescope, together with the S40/450.
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The Asiago Archive -1
Images
122 cm (9x12 cm)
1942- 1997
nr. 9720
Spectra
Newtonian spectrographs of
the 122 cm
1958- 1991
nr. 3220
Spectra
Cassegrain spectrographs of
the 122 cm
1951- 1994
nr.18584
Images
182 cm (12x20 cm)
1973- 1989
nr. 3870
Spectra
182 cm
1973- 1988
nr. 4301
Images
1966- 1998
nr.16729
1966- 1998
nr. 1087
Images (films)
Schmidt S67/92 cm
(20x20cm)
Schmidt S67/92 cm
(20x20cm)
Schmidt S40/50 cm (10cm)
1958- 1992
nr.18411
Objective prism (films)
Schmidt S40/50 cm (10cm)
1958 -1992
nr. 2006
Objective prism plates
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The status of the Asiago archive
The digital logbooks of all the Asiago telescopes, and of the objective prism
spectra of the S67/92-cm and S40/50-cm telescopes are accessible on-line
(www.pd.astro.it/Asiago/7000/7020.html), with a query program.
Some 2500 plates have been already digitized, their list can be found in a file on
that page.
Their utilization by the International community is already very active.
The digital files are stored both on DVDs and in a 600 GByte Network Attached
Storage unit that will be put on line in the near future, but already needs
expansion.
Left: the NAS unit. Right: one of the 3 Asiago working places.
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The first plates - 1
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First plate with the 182 cm, and
optical quality
Left, the first plate, March 8, 1973.
Above: the excellent optical quality of the f/9
Cassegrain focus.
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The S67/92cm plate distribution, the
Sa57 calibration curve
The S67/92cm distribution of plates is far from being evenly distributed.The limiting
useful magnitude is around 18.5 (better than that until 1975).
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The light curve of 3C 345
The Asiago Observatory carried out since 1967 a large scale survey of Quasar
Variability. Many plates were acquired and reduced with traditional methods, but
most of them were not published. We intend to redo this work on the digitized
material. Here is an example for 3C 345 (Omizzolo, A., Barbieri, C., Rossi, C.
2005, MNRAS), left the light curve from 1967 until 1990, right the difference eyescanner. But indeed, these plates contain some 50 more quasars (unknown at the
time of the discovery of 3C 345), which we plan to analyze as soon as possible.
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The BL Lac Object S5 0716+714
Another interesting paper on QSO variability is:
The Long Term Optical Variability of the BL Lac object S5 0716+714:
Evidence for a Precessing Jet (R. Nesci, E. Massaro, C. Rossi, S. Sclavi, M.
Maesano, F. Montagni, Astron. Journal 2005), which used also the S40/50 films.
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The T-Tau KH 15 D
star
KH 15 D is a remarkable pre-main
sequence binary star with deep long
lasting periodic eclipses.
BVRI Photometry of KH15D over the
last five decades has been derived from
several digitized photographic archives
(including Asiago).
Dr. J. Johnson (Berkeley) has produced
and left in Asiago, after his stay, a very
useful IDL-based photometric program
that can handle entire batches of plates.
(Johnson J.A., Winn N., Rampazzi F.,
Barbieri C., Mito H., Tarusawa T., Tsvetkov
M., Borisova A., Meusinger H. (2005). The
History Of The Mysterious Eclipses Of KH
15D II. Asiago, Kiso, Kitt Peak, Mt. Wilson,
Palomar, Tautenburg And Rozhen
Observatories, 1954-97 (2005).
Astronomical Journal.
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McNeil's Nebula
The Asiago archive has provided a very
useful record of the brightening episode
in 1967-68, excluding other more recent
similar instances .
(from C. Aspin, B. Reipurt and the
Asiago staff, 2005, in preparation).
left: all B Asiago images
right: all I Asiago images.
The I-plates archive, obtained mostly by Paolo Maffei on Milky Way fields,
is still largely unexplored.
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Variables in M33 and M31
The Asiago plates permit to study the
Hubble-Sandage variables in M33 (top).
The same is true for M31(bottom, Var. nr. 19
on 3 different plates).
All plates of those two fields are already
available in digital form. It's a very rich
material which can be accessed by all
interested astronomers.
Three different plates of var. 19 in M31. Left: 182 cm, center 122 cm, right S67/92 cm.
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The misterious Of, X-ray star HD108
Only 3 such stars as HD108 are known. The Asiago material covers
approximately 15 years from 1953 to 1967, from the very blue to H-alpha. Only
the oldest plates have been examined and published (Mannino and Humblet,
Annales d’Astrophysique 18e Année - N° 4, pag. 237-258, 1955, and
Contributi Osservatorio Astrofisico Asiago nr. 89, 1958). Emission,
absorptions, P-Cyg lines are well visible and measurable.
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More on the linearization procedure - 1
(These results are essentially due to Andrea di Paola, Rome).
To obtain linearization, we derive sets of secondary standards using the CCD
camera of Campo Imperatore. Fig. 1a shows an example for an near-IR plate.
The resulting characteristic
curve has been fitted with a
double exponential function
like:

 
mplate  a 1  e k ( mb )  c 1  e hm
and applied to each pixel
of the digitized plate.
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
More on the linearization procedure - 2
The results show a 6 magnitudes useful dynamic range and less than 0.1
magnitudes standard deviation of residuals.
We also verified that upon constant and good development conditions, all the
plates from the same emulsion share the same characteristic curve and can be
linearized using the same function.
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More on the linearization procedure - 3
After having linearized all the available M42 plates from the Asiago Astrophysical
Observatory archive obtained with the 103aO emulsion and the GG13 filter (very
similar to Johnson B filter) we performed a variability search on a nearly 30 years
period. This search produced many candidates besides confirming known objects
such as Y-Ori, BV-Ori and TT-Ori.
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The Torino Archive (~6000 plates)
Images
Zeiss astrograph , 20 cm,
1923 - 1984 max
nr. 3000
18x24
Images
Morais refractor, 38 cm
1971 - 1980 max
nr. 1000
20x20
Images
REOSC reflector, 105 cm
1971 - 1994 max
nr. 1000
16x16
Images
GPO-ESO refractor, 40 cm
Images with offsite telescopes
(ESO-GPO, Cape Town, La
Palma)
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1978 – 1990 16x16
nr.
700
few
hundreds
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Old plates from OATo archive
The Pons-Winneke comet, M42, the Pleiades, plates exposed in 1927 at the Zeiss
telescope of the Osservatorio Astronomico di Torino.
Low resolution (600dpi) JPEG scans are provided for each archived plate.
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Inspection & Archiving at OATo
Plates are inspected with a binocular microscope to check emulsion
status and image quality.
Plates are cleaned and stored in high-density polyethylene (HDP)
envelopes for better protection.
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Plates archiving at OATo
Archive Room
Measuring machine TO.CA.M.M.
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The Catania Archive
Instrument and Period
33cm equatorial astrograph (Catania)
(1897-1907)
33cm equatorial astrograph (Catania)
(1910)
33cm equatorial astrograph (Catania)
(1956-1964)
S61/41 Schmidt Telescope (Mt. Etna)
(1968-1992)
33cm photographic objective (Mt.
Etna) (1985-1992)
Project
Astrographic Catalogue + Carte du Ciel
 1600 plates (16x16cm) **
Halley comet
32 plates (16x16cm)
Fields of Catania astrographic zone
 100 plates (16x16cm)
Direct images
 1200 plates (9x9cm)
Direct images
 100 plates (16x16cm)
** only approximately 200 in acceptable conditions!
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A plate of the Carte du Ciel 1896
Plate nr. 26, obtained on July 1, 1896, is still usable, but most
have gone forever.
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Halley Comet and the great comet 1910a
Upper left panel: the great
australis comet1910a;
The other 3 panels are of comet
Halley.
Lower panel: a digital Sekaninatype filter applied to one of the
Catania images.
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Plates from
the Vatican
Archive - 1
A plate from the Astrographic Catalog. The logbooks were published. The
archive is extremely well kept and ordered.
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Plates from the Vatican Archive - 2
An objective prism plate
obtained with the Vatican
Schmidt in Castelgandolfo.
Many plates were taken in
Milky Way fields with platefilter-prism combination that
effectively selected stars with
Halpha emissions
(e.g. G. Coyne et al., Vatican
Observatory Publ. Vol. 1 nr. 5,
1974)
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Future plans (if funded…)
•
•
•
complete the storage and the digitization of the log-books (almost finished
in all places)
continue to accept proposals from the International community, in order to
selectively digitize those plates that give a maximum scientific return.
The very nature of this project calls for its harmonisation with the concept
of Virtual Observatory. The added value photographic plates can bring to
the VO is to enhance the time axis of the VO multi-dimensional space. We
plan to coordinate our work with the Italian activities for the Datagrid and
national Virtual Observatory (DRACO). As such, the use of the standards
defined within the working groups of the International VO Alliance
(IVOA) is envisaged, and data are planned to be eventually accessible to
the community at large through the VO.
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