MIRAPROC Keyword


The MIRAPROC keyword is used by the Express Image Calibration command to encode calibration information into the FITS header. This keyword has a string value with "0" and "1" characters at assigned position to encode the success of each calibration step. Initially, the string is all zero's, but each calibration step sets a "1" digit at a position for that calibration step. For example, a simple bias frame subtraction enters a "1" at position 0, on the left end of the keyword string. This is also used by Mira to block repeat application of specific calibration steps. The string is only as long as needed and expands its length as necessary.

Example

Suppose the Express Image Calibration command applies a bias frame, applies a dark frame after scaling by exposure time, and applies a master flat frame. According to the table below, the image header would add a MIRAPROC keyword line with a "1" in positions 0, 9, and 14:

MIRAPROC      '100000000100001'

If you ran another calibration to apply only a pixel mask, the MIRAPROC keyword would update as follows:

MIRAPROC      '1000000001000010000000001'

MIRAPROC Calibration Flags and Positions

The table below lists the currently used processing flags. Note that the first string position is at position 0, on the left end of the string. Some processing flags shown below are not used to allow for future expansion

Processing Flag

Position

Apply bias frame

0

Apply pattern bias frame (unused)

1

Apply bias value

2

Apply column bias

3

Apply row bias

4

Apply erase line bias

5

 

 

Apply dark frame

8

Apply scaled dark frame

9

Apply optimized dark frame

10

Apply nearest dark frame (unused)

11

 

 

Apply master flat frame

14

Apply illumination flat frame

15

Apply pixel flat frame

16

 

 

Combine multiple images

20

Normalize image

21

 

 

Apply pixel mask

24

Apply region mask

25

Apply cosmic ray filter

26

Trim image to smaller size

27

 

 

Subtract background fit

30

Divide background fit

31

 

Related Topics

Express Image Calibration, FITS Keywords, FITS Format Definition, FITS Header Pane, FITS Header Editor, Modify Keywords