Table of Contents

Class FitsHeaderConstants

Namespace
FitsModel
Assembly
FitsModel.dll

3.3.1. Primary header
The header of a primary HDU shall consist of one or more header blocks, each containing a series of 80-character keyword records containing only the restricted set of ASCII-text characters. Each 2880-byte header block contains 36 keyword records. The last header block must contain the END keyword (defined in Sect. 4.4.1), which marks the logical end of the header. Keyword records without information (e.g., following the END keyword) shall be filled with ASCII spaces (decimal 32 or hexadecimal 20).

public static class FitsHeaderConstants
Inheritance
FitsHeaderConstants
Inherited Members

Fields

BZeroStr

The FITS format does not support a native unsigned integer data type(except for the unsigned 8-bit byte data type) therefore un- signed 16-bit, 32-bit, or 64-bit binary integers cannot be stored directly in a FITS data array.Instead, the appropriate offset must be applied to the unsigned integer to shift the value into the range of the corresponding signed integer, which is then stored in the FITS file.The BZERO keyword shall record the amount of the offset needed to restore the original unsigned value.The BSCALE keyword shall have the default value of 1.0 in this case, and the appropriate BZERO value, as a function of BITPIX, is specified in Table 11

public const string BZeroStr = "BZERO"

Field Value

string

BitPixStr

4.4.1.1. Primary header
The value field shall contain an integer. The absolute value is used in computing the sizes of data structures. It shall specify the number of bits that represent a data value in the associated data array. The only valid values of BITPIX are given here.

public const string BitPixStr = "BITPIX"

Field Value

string

BlockSize

3.3.1. Primary header
A sequence of 2880 eight-bit bytes aligned on 2880-byte boundaries in the FITS file, most commonly either a header block or a data block.Special records are another infrequently used type of FITS block.This block length was chosen because it is evenly divisible by the byte and word lengths of all known computer systems at the time FITS was developed in 1979.

public const int BlockSize = 2880

Field Value

int

Comment

This keyword may be used to supply any comments regarding the FITS file.

public const string Comment = "COMMENT"

Field Value

string

EndRecord

This keyword has no associated value. Bytes 9 through 80 shall be filled with ASCII spaces(decimal 32 or hexadecimal 20). The END keyword marks the logical end of the header and must occur in the last 2880-byte FITS block of the header.

public const string EndRecord = "END                                                                             "

Field Value

string

ExtensionMandatoryKeywords

Set of keywords that are mandatory in an extension header of a FITS file.

public static readonly string[] ExtensionMandatoryKeywords

Field Value

string[]

ExtensionStr

The value field shall contain a character string giving the name of the extension type.This keyword is mandatory for an extension header and must not appear in the primary header.7 To preclude conflict, extension type names must be registered with the IAUFWG.The current list of registered extensions is given in Appendix F. An up-to-date list is also maintained on the FITS Support Office website.

public const string ExtensionStr = "XTENSION"

Field Value

string

GCountStr

The value field shall contain an integer that shall be used in any way appropriate to define the data structure , consistent with Eq. 2. This keyword must have the value 1 in the IMAGE, TABLE, and BINTABLE standard extensions defined in Sect. 7. This keyword is also used in the random-groups structure(Sect. 6) to specify the number of random groups present

public const string GCountStr = "GCOUNT"

Field Value

string

KeywordSize

3.3.1. Primary header
The first eight bytes of a keyword record, which contain the ASCII name of a metadata quantity(unless it is blank).

public const int KeywordSize = 8

Field Value

int

NAxis

The value field shall contain a non-negative integer no greater than 999 representing the number of axes in the associated data array.A value of zero signifies that no data follow the header in the HDU.

public const string NAxis = "NAXIS"

Field Value

string

NumDataBlockRecords

The number of records in a 2880 byte data block.

public const int NumDataBlockRecords = 36

Field Value

int

PCountStr

The value field shall contain an integer that shall be used in any way appropriate to define the data structure, consistent with Eq. 2. In IMAGE (Sect. 7.1) and TABLE(Sect. 7.2) extensions this keyword must have the value 0; in BINTABLE extensions (Sect. 7.3) it is used to specify the number of bytes that follow the main data table in the supplemental data area called the heap.This keyword is also used in the random-groups structure(Sect. 6) to specify the number of parameters preceding each array in a group.

public const string PCountStr = "PCOUNT"

Field Value

string

PrimaryHeaderMandatoryKeywords

Set of keywords that are mandatory in the primary header of a FITS file.

public static readonly string[] PrimaryHeaderMandatoryKeywords

Field Value

string[]

RecordSize

3.3.1. Primary header
An 80-character record in a header block consisting of a keyword name in the first eight characters followed by an optional value indicator, value, and comment string. The keyword record shall be composed only of the restricted set of ASCII-text characters ranging from decimal 32 to 126 (hexadecimal 20 to 7E).

public const int RecordSize = 80

Field Value

int

Simple

The SIMPLE keyword is required to be the first keyword in the primary header of all FITS files.

public const string Simple = "SIMPLE"

Field Value

string

SimpleRawEntry

Full length string representation of the SIMPLE keyword record.

public const string SimpleRawEntry = "SIMPLE  =                    T / conforms to FITS standard                      "

Field Value

string

ValueSize

In keyword records that contain the value indicator in Bytes 9 and 10, the remaining Bytes 11 through 80 of the record shall contain the value, if any, of the keyword, followed by optional comments. In keyword records without a value indicator, Bytes 9 through 80 should be interpreted as commentary text, however, this does not preclude conventions that interpret the content of these bytes in other ways.

public const int ValueSize = 70

Field Value

int

ValueStart

If the two ASCII characters '= ' (decimal 61 followed by decimal 32) are present in Bytes 9 and 10 of the keyword record, this indicates that the keyword has a value field associated with it, unless it is one of the commentary keywords defined in Sect. 4.4.2 (i.e., a HISTORY, COMMENT, or completely blank keyword name), which, by definition, have no value

public const int ValueStart = 10

Field Value

int
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