Working with Multiple Files

import procastro as pa

Files can be loaded from a directory with standard glob.glob wildcards.

ad =  pa.AstroDir("*.fits")

Find files with easy filtering function .filter() that supports handling the value of any header of the FITS file, including negate NOT, numerical comparison LT and GT, or partial string MATCH.

# either with logical OR
ad_after_or_filter = ad.filter(name_match="wasp", exptime=120)

# or with logical AND
ad_after_and_filter = ad.filter(name_not_match="wasp").filter(exptime_lt=120)

also with easy indexing and mixing

ad_selected = ad[ad["exptime"] > 10]
ad_selected = ad[:5] + ad[7:]

requesting header or data values for the whole group of files can be done with the values() or data() methods:

list_of_headers_per_file = ad.values(["EXPTIME", "filename", "JD-OBS"])
array_of_nfiles_dimension = ad.get_datacube()

An AstroDir is just a collection of AstroFile that can do other tricks,

af = ad[0]

Depending on the indexing type, it has different returns:

# if using an string returns the header value
af['exptime']

# otherwise, it refers to the data itself
af[100:200, 300: 450]  # if data is 2D

It also supports mathematical operations on the data directly, and logical operations on the header previously defined as sortkey (filename by default)

af /= 100
af_sum = ad[0]+ad[1]

ad.add_sortkey("EXPTIME")
test = ad[0] < ad[2]

Note that all the headers are read and cached upon creation of an AstroDir. Further, there is also a cache of data up to a maximum number of files. The default of 200 cached files can be changed with

from procastro import astrofile_cache
astrofile_cache.set_max_cache(100)

Whenever the data cache is full it will read from disk