Information on Service 'Corrections to USNO-B plates from PPMX'

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This table contains, for each field that went into USNO-B1, a correction derived from matching the USNO-B1 positions for that plate with the PPMX ones (used as a representation of ICRS) and deriving a mean offset of the objects from that particular plate for them. We did not attempt to derive magnitude-dependent corrections (although it is known that the true residuals depend on both magnitude and color).

For a list of all services and tables belonging to this service's resource, see Information on resource 'The USNO-B 1.0 Catalog'

Overview

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This service is not published. This can mean that it was deemed too unimportant, for internal use only, or is just a helper for a published service. Equally likely, however, it is under development, abandoned in development or otherwise unfinished. Exercise caution.

Other services provided on the underlying data include:

Spatial Coverage

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

NameTable Head DescriptionUnitUCD
field Field# Field number in survey N/A obs.field
nTotal N Number of objects in estimate N/A meta.number
survey Survey ID Survey identifier, see long docs N/A meta.id

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

NameTable Head DescriptionUnitUCD
da d(alpha) Mean offset in alpha deg arith.diff;pos.eq.ra
dd d(delta) Mean offset in delta deg arith.diff;pos.eq.dec
field Field# Field number in survey N/A obs.field
nTotal N Number of objects in estimate N/A meta.number
survey Survey ID Survey identifier, see long docs N/A meta.id

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

NameTable Head DescriptionUnitUCD Verb. Level
survey Survey ID Survey identifier, see long docs N/A meta.id 20
field Field# Field number in survey N/A obs.field 20
da d(alpha) Mean offset in alpha deg arith.diff;pos.eq.ra 20
dd d(delta) Mean offset in delta deg arith.diff;pos.eq.dec 20
nTotal N Number of objects in estimate N/A meta.number 20

This service uses code provided by Astrometry.net. For more details visit http://astrometry.net. The field metadata were, in part, taken from CDS' Vizier service.

VOResource XML (that's something exclusively for VO nerds)