Information on resource 'DASCH in the VO'
This is a re-publication of the metadata from StarGlass, an
information service operated by Harvard College Observatory (HCO)
which primarily indexes the holdings of the HCO Astronomical
Photographic Glass Plate Collection. This collection is the world's
largest archive of astronomical photographic glass plates, consisting
of more than 550,000 images documenting the entire sky over a
century-long time baseline. Approximately 430,000 plates in the
collection, representing the subset of sky images deemed suitable for
astrometric and photometric calibration, have been digitized at high
resolution by the DASCH project. StarGlass makes available both
photographs and calibrated scientific data when available. This
resource re-publishes the metadata in separate tables for “narrow” and
“wide” (extremely wide-field) plates. The narrow plates are also
published in an obscore table and as a SIAP2 service.
Services defined within this resource descriptor
- DASCH Product Access
Yield pre-authenticated links to DASCH data products. Successful calls
will redirect the the artefact in question.
- DASCH SIAP2
SIAP2 service over the DASCH (Harvard) plates. Please note that a
substantial number of plates has no calibration and hence will not be
found using SIAP2 queries with positional constraints. Also, this
service only returns ”narrow” plates, which here excludes plates from
instruments with a field of view above 200 square degrees.
- DASCH VO Datalink Service
This service generates authorised links to access DASCH FITS files. To
avoid unneccessary large downloads, the #this link is a downsampled
image. To retrieve full-resolution FITS-es, look for rows with
semantics="#coderived" and local semantics full-res.
Tables defined within this resource descriptor
- dasch.narrow_plates – queryable through TAP and ADQL
This table holds metadata for the parts of DASCH counting as targeted
observations (plate scale below 400 arcsec/mm. “Patrol” and “Meteor”
plates in DASCH nomenclature are found in the wide_plates table.
- dasch.plates – queryable through TAP and ADQL
This table is a union of the narrow_plates and wide_plates tables. For
non-historic use, you probably get better results looking at
narrow_plates.
- dasch.wide_plates – queryable through TAP and ADQL
This table holds metadata for the “Patrol” and “Meteor” plates from
DASCH, i.e., very wide-field observations presumably not useful in
global discovery. These data products are therefore not re-published
through obscore. For the “narrow” plates, see the narrow_plates table.
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