Skip to content

Basic Keywords

Items of Basic Header Dictionary

Keywords that can be commonly used for multiple science instruments are included in the Basic Header Dictionary. The items of the Basic Header Dictionary mean as follows:

Keyword
It is a FITS header keyword.
Revised
It indicates a date when the latest update is published
Importance

It indicates a category of importance. It has values below. Please note that when an instrument-specific keyword has the same meaning as any of the basic header keywords categorized as Optional, that basic header keyword precedes the instrument-specific keyword.

Value Category of importance
Common Essential keyword
Imaging Essential keyword for imaging data
Spectroscopy Essential keyword for data from spectroscopic observation
Polarimetry Essential keyword for data from polarimetry
Object Essential keyword for science frames
Optional Keywords are defined, but are not essential
Queue Essential for data from an instrument that is executed in queue-mode observation
Alias
It is a designated keyword for obtaining a status from OBS (Gen2) with use of the tool kit Status Distribution Service. When Toolkit is written here, input through the Toolkit (to create data in a FITS format) is possible. When Next Toolkit is written here instead, a tool will be provided in the next version of the Toolkit.
The format of FITS.SBR.???? is used for header keywords that are common to all the science instruments, while FITS.#Inst.???? is applied to header keywords whose a reference status varies with the instruments. #Inst is an abbreviation of an instrument indicated in three characters. See the Instrument Codes.
Value Format
It indicates a description format of a keyword value.
Type
It indicates a data type of a keyword value.
Unit
It indicates a unit of a keyword value. In principle, this designated unit shall be used for the unit of the keyword value; provided, however, that in case any issue inevitably arises, inquiry shall be made to the person in charge at Subaru Telescope.
Recommend
It indicates a specific value recommended by Subaru Telescope. Unless any conflict arises, this value shall be used. Recommended values shall be always used for SIMPLE and OBSERVAT.
Obsolete
If a keyword is marked Obsolete, the keyword should not be used for new instruments, while the use of them are allowed for existing FITS files.
Comment
It describes an in-line comment in a FITS header. When a value requires a unit, description of the unit shall be included.
Description
It defines a keyword’s meaning.

Basic Header Keyword Dictionaries for the Subaru Telescope

Obsolete Dictionaries