Further access options are discussed below
For a list of all services and tables belonging to this service's resource, see Information on resource 'Intermediate and Apparent Places of Fundamental Stars'
APFS stands for "Apparent Places of Fundamental Stars", a term which we maintain due to its traditional use; introductorily, it might be appropriate to address the following issues:
The dates and times in this service are taken as and given in Terrestrial Time (TT).
TT is related to Coordinated Universal Time (UTC) by:
TT = UTC + Delta(AT) + 32.184 sec
where Delta(AT) is an integer term depending on irregularities of the Earth's rotation. In 2006: Delta(AT) = 33 sec. The current value for Delta(AT) can be found in IERS Bulletin C.
That means that TT and UTC differ by roughly one minute. The computed apparent places are usually not affected by this difference in time-scale, except the last given digit of right ascensions for stars near the poles (as an effect of the underlying spherical coordinate system). In any case, if apparent places are used for conventional geodetic applications there is no need to consider this intricateness, and UTC may be set instead of TT. UTC is the civil time as disseminated by radio or TV, corrected for your time zone.
Software Routines from the IAU SOFA Collection were used. Copyright © International Astronomical Union Standards of Fundamental Astronomy (http://www.iausofa.org)
Parts of this work make use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
You can access this service using:
This service is published as follows:
local means it is listed on our front page, ivo_managed means it has a record in the VO registry.
Other services provided on the underlying data include:
The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):
|endDate||End date||End date of generated ephemeris||N/A||N/A|
|hrInterval||Interval of generation (hrs)||Number of hours between two apparent positions||N/A||N/A|
|object||Object||Enter an FK6 number here, or a (decimal, comma-seperated) position, or simbad identifier to use the closest FK6 star.||N/A||N/A|
|startDate||Start date||Start date of generated ephemeris||N/A||N/A|
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.
|arg_hour||Hour (TT)||Hour of epoch (TT)||hour||time|
|dec||δ||Declination of object at epoch||deg||eq.pos.dec|
|isodate||Date||Date of epoch (TT)||d||time.epoch|
|raCio||α (CIO)||Right ascension of object at epoch in the CIO system||deg||eq.pos.ra|
|raEqu||α (Equinox)||Right ascension of object at epoch in the old equinox system||deg||eq.pos.ra|
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.
|Name||Table Head||Description||Unit||UCD||Verb. Level|
|isodate||Date||Date of epoch (TT)||d||time.epoch||1|
|arg_hour||Hour (TT)||Hour of epoch (TT)||hour||time||1|
|raCio||α (CIO)||Right ascension of object at epoch in the CIO system||deg||eq.pos.ra||1|
|dec||δ||Declination of object at epoch||deg||eq.pos.dec||1|
|raEqu||α (Equinox)||Right ascension of object at epoch in the old equinox system||deg||eq.pos.ra||20|
VOResource XML (that's something exclusively for VO nerds)