| Description: ! The NRAO VLA Sky Survey is currently underway at the VLA and data is made available to the public as soon as processed. i SkyView /i has copied the NVSS intensity data from the NRAO FTP site. The full NVSS survey data includes information on other Stokes parameters. Note that i SkyView /i may be slightly out of date with regard to the latest releases of NVSS data. The current information was copied in November 1997. p Observations for the 1.4 GHz NRAO VLA Sky Survey (NVSS) began in 1993 September and should cover the sky north of -40 deg declination (82% of the celestial sphere) before the end of 1996. The principal data products will be: ol li A set of 2326 continuum map "cubes," each covering 4 deg X 4 deg with three planes containing Stokes I, Q, and U images. These maps were made with a relatively large restoring beam (45 arcsec FWHM) to yield the high surface-brightness sensitivity needed for completeness and photometric accuracy. Their rms brightness fluctuations are about 0.45 mJy/beam = 0.14 K (Stokes I) and 0.29 mJy/beam = 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from 0.3 arcsec for strong (S 30 mJy) point sources to 5 arcsec for the faintest (S = 2.5 mJy) detectable sources. li Lists of discrete sources. /ol The NVSS is being made as a service to the astronomical community, and the data products are being released as soon as they are produced and verified. P The NVSS survey is included on the bSkyView High Resolution Radio Coverage /b"http://skyview.gsfc.nasa.gov/images/high_res_radio.jpg" map/a. This map shows coverage on an Aitoff projection of the sky in equatorial coordinates. p ]] |
| Completely compliant |
| Service URL |
| Input Parameter | Required | Present |
|---|---|---|
| Regular parameters: | ||
| POS | MUST | Yes |
| SIZE | MUST | Yes |
| INTERSECT | MAY | No |
| NAXIS | MAY | Yes |
| CFRAME | MAY | Yes |
| EQUINOX | MAY | Yes |
| CRPIX | MAY | No |
| CRVAL | MAY | No |
| CDELT | MAY | No |
| ROTANG | MAY | No |
| PROJ | MAY | Yes |
| FORMAT | MUST | Yes |
| Service specific parameters | ||
| INTERPOLATION | MAY | Yes |
| big | MAY | Yes |
| small | MAY | Yes |
| Field UCD | Required | Present | Required datatype |
Actual datatype |
|---|---|---|---|---|
| Regular fields: | ||||
| VOX:Image_Title | MUST | Yes | char | char |
| INST_ID | SHOULD | No | char | |
| VOX:Image_MJDateObs | SHOULD | No | double | |
| POS_EQ_RA_MAIN | MUST | Yes | double | double |
| POS_EQ_DEC_MAIN | MUST | Yes | double | double |
| VOX:Image_Naxes | MUST | Yes | int | int |
| VOX:Image_Naxis | MUST | Yes | int | int |
| VOX:Image_Scale | MUST | Yes | double | double |
| VOX:Image_Format | MUST | Yes | char | char |
| VOX:STC_CoordRefFrame | SHOULD | No | char | |
| VOX:STC_CoordEquinox | MAY | No | double | |
| VOX:WCS_CoordProjection | SHOULD | No | char | |
| VOX:WCS_CoordRefPixel | SHOULD | No | double | |
| VOX:WCS_CoordRefValue | SHOULD | No | double | |
| VOX:WCS_CDMatrix | SHOULD | No | double | |
| VOX:BandPass_ID | SHOULD | No | char | |
| VOX:BandPass_Unit | SHOULD | No | char | |
| VOX:BandPass_RefValue | SHOULD | No | double | |
| VOX:BandPass_HiLimit | SHOULD | No | double | |
| VOX:BandPass_LoLimit | SHOULD | No | double | |
| VOX:Image_PixFlags | SHOULD | Yes | char | char |
| VOX:Image_AccessReference | MUST | Yes | char | char |
| Service specific fields: | ||||
| VOX:LogicalName | MAY | YES | char | |