3.1.10. stackFramesMXCal

Stack MAROON-X calibration frames with etalon flux scaling.

MX-specific version of stackFrames for calibration frames - changes scaling to average full frame mean to purposely scale by etalon flux and its drift between calibration exposures. This function should not be used to combine MX science frames.

3.1.10.1. Parameters

adinputslist of AstroData

Any set of 2D.

suffixstr

Suffix to be added to output files.

apply_dqbool

Apply DQ mask to data before combining?

nlow, nhighint

Number of low and high pixels to reject, for the ‘minmax’ method. The way it works is inherited from IRAF: the fraction is specified as the number of high and low pixels, the nhigh and nlow parameters, when data from all the input images are used. If pixels have been rejected by offseting, masking, or thresholding then a matching fraction of the remaining pixels, truncated to an integer, are used. Thus:

nl = n * nlow/nimages + 0.001
nh = n * nhigh/nimages + 0.001

where n is the number of pixels surviving offseting, masking, and thresholding, nimages is the number of input images, nlow and nhigh are task parameters and nl and nh are the final number of low and high pixels rejected by the algorithm. The factor of 0.001 is to adjust for rounding of the ratio.

operationstr

Combine method.

reject_methodstr

Pixel rejection method (none, minmax, sigclip, varclip).

zerobool

Apply zero-level offset to match background levels?

scalebool

Scale images to the same intensity?

memoryfloat or None

Available memory (in GB) for stacking calculations.

statsecstr

Section for statistics.

separate_extbool

Handle extensions separately?

3.1.10.2. Returns

list of AstroData: Sky stacked image. This list contains only one element. The list format is maintained so this primitive is consistent with all the others.

3.1.10.3. Raises

IOError: If the number of extensions in any of the AstroData objects is different.
IOError: If the shape of any extension in any AstroData object is different.
AssertError: If any of the .gain() descriptors is None.
AssertError: If any of the .read_noise() descriptors is None.

3.1.10.4. Parameter defaults and options

suffix               '_stack'             Filename suffix
apply_dq             True                 Use DQ to mask bad pixels?
statsec              None                 Section for statistics (1-indexed, inclusive-max, x-first)
operation            'mean'               Averaging operation
   Allowed values:
     mean    arithmetic mean
     wtmean  variance-weighted mean
     median  median
     lmedian low-median

reject_method        'sigclip'            Pixel rejection method
   Allowed values:
     none    no rejection
     minmax  reject highest and lowest pixels
     sigclip reject pixels based on scatter
     varclip reject pixels based on variance array

hsigma               3.0                  High rejection threshold (sigma)
     Valid Range = [0,inf)
lsigma               3.0                  Low rejection threshold (sigma)
     Valid Range = [0,inf)
mclip                True                 Use median for sigma-clipping?
max_iters            None                 Maximum number of clipping iterations
     Valid Range = [1,inf)
nlow                 0                    Number of low pixels to reject
     Valid Range = [0,inf)
nhigh                0                    Number of high pixels to reject
     Valid Range = [0,inf)
memory               1.0                  Memory available for stacking (GB)
     Valid Range = [0.01,inf)
save_rejection_map   False                Save rejection map?
separate_ext         True                 Handle extensions separately?
scale                True                 Scale images to the same intensity?
zero                 False                Apply additive offsets to images to match intensity?

3.1.10.5. Algorithm

Todo

add description

3.1.10.6. Issues and Limitations

Todo

add description