This table holds the metadata we expect to be used in searching for archived images, covering the basic spatial, spectral, and (soon) temporal information. Images are ingested in sets of one or more FITS files, along with a Tar archive of information about their generation (The image_products table contains information common to all the images of the set).
Definition:
Column | Type | Collation | Nullable | Default
---------------------+------------------------+-----------+----------+------------------------------------------
image_id | integer | | not null | nextval('images_image_id_seq'::regclass)file_id | integer | | not null |
target_name | character varying | | not null |
telescope | character varying | | not null |
thumbnail | bytea | | |
spatial_resolution | double precision | | not null |
image_field_of_view | double precision | | not null |
max_intensity | double precision | | not null |
min_intensity | double precision | | not null |
rms_noise | double precision | | not null |
polarization_id | integer | | not null |
ra | character varying(255) | | not null |
dec | character varying(255) | | not null |
min_frequency | double precision | | not null |
max_frequency | double precision | | not null |
ra_element_count | integer | | not null |
dec_element_count | integer | | not null |
starttime | double precision | | |
endtime | double precision | | |
exposure_time | double precision | | |
rest_frequency | double precision | | |
image_units | character varying(255) | | |
spatial_region | text | | |
beam_axis_ratio | double precision | | |
band_code | character varying | | |
ra_pixel_size | double precision | | not null |
dec_pixel_size | double precision | | not null |
tags | character varying | | |
image_products_id | integer | | |
Indexes:
"image_id" PRIMARY KEY, btree (image_id)
Foreign-key constraints:
"files_images_fk" FOREIGN KEY (file_id) REFERENCES files(file_id) ON UPDATE CASCADE ON DELETE CASCADE
"images_image_products_id_fkey" FOREIGN KEY (image_products_id) REFERENCES image_products(image_product_id)
"polarizations_images_fk" FOREIGN KEY (polarization_id) REFERENCES polarizations(polarization_id)
Columns:
image_id: an automatically generated unique identifier for the image
file_id: the identifier for the FITS file this metadata describes
target_name: name of the object in the image, if available
telescope: the telescope(s) used in the image creation
thumbnail: the path to a thumbnail image in our thumbnails cache
spatial_resolution: an approximate size of the synthesized beam (note this is not the pixel size of the image, but the true resolution)
image_field_of_view: the extent of the sky covered by the image
max_intensity: the maximum of the image data
min_intensity: the minimum of the image data
rms_noise: the root-mean-square of a source-less region of the image
polarization_id: table value associated with the polarization of the image
ra: central right ascension of the image. Units: Degrees
dec: central declination of the image. Units: Degrees
min_frequency: minimum frequency used in image creation
max_frequency: maximum frequency used in image creation
ra_element_count: size of the data in the ra axis
dec_element_count: size of the data in the dec axis
starttime: earliest data used in image creation
endtime: latest data used in image creation
exposure_time: (not yet determinable) the total time on source for the image
rest_frequency: center frequency of the image in the local rest frame of reference
image_units: units of intensity used
spatial_region: a VO compatible designation of the region the image covers (Dowler, et al 2010)
beam_axis_ration: characterizes the shape of the synthesized beam
band_code: the radio band designation code(s) used in the image
ra_pixel_size: the image pixel size in the ra dimension
dec_pixel_size: the image pixel size in the dec dimension
tags: any tags applied to this image
image_products_id: link to the associated image_products metadata for this image.