4.2 Input parameters ########################################## Where to start ? ------------------------ The photometry script is contained in the file "05_photometry\\photometry_run.py". To execute the script, just edit the file, modify the input parameters, save the updated file and execute the script by double-click on the file icon in Windows. The following 3 input parameters must be provided: - the names of the input images - the sizes of the disks for photometry - a generic name to be used to create the output files Names of the input images --------------------------- The input images must be provided in a list, as follows: :: Imagelist = ['C:\\image1.fit', 'C:\\image2.fit', 'C:\\image3.fit'] In fact, exactly the same list is obtained with this statement: :: Imagelist = ['C:\\image' + str(i+1) + '.fit' for i in range(3)] This technique used to construct the image list is called a "list comprehension" (it is further described on the Python website, at `this link `_). It is very powerful, and allows to specify any number of images. For instance this list contains 700 images: :: Imagelist = ['C:\\image' + str(i+1) + '.fit' for i in range(700)] The list comprehension can be more elaborate: :: Imagelist = ['C:\\image' + str(i+1) + '.fit' for i in range(700) if i+1 not in [233,242,423,433]] Of course a separate variable can be used to store the path: :: Path = 'C:\\Desktop\\24Jan2010\\ProcessedImages\\' Imagelist = [Path + 'image' + str(i+1) + '.fit' for i in range(100)] Be careful, in Python the path or filenames with non-ASCII characters do not work by default. To use them, the string must be preceded by a 'u' (for Unicode), as in the example below where accents are required in the name of the path. :: Path = u"C:\\Desktop\\Jerome\\24Jan2010\\ProcessedImages\\" Imagelist = [Path + 'image' + str(i+1) + '.fit' for i in range(100)] Disk sizes for photometry --------------------------- To do photometry we need 3 different disk sizes: - the first size is the radius (in pixels) of the internal disk : all the pixel inside this disk are summed to get the star signal - the second and third size correspond to the internal and external radii (in pixels) of a ring. The median value of all pixels inside this ring corresponds to the sky background Since the script is using several disk sizes in parallel, we must provide a list of such sets of 3 radii. For instance, we can write: :: sizes = [[2,8,40],[2.5,8,40],[3,8,40],[3.5,8,40],[4,8,40],[4.5,8,40],[5,8,40]] Or, for one single set of photometry disks: :: sizes = [[3,8,40]] Generic name for output files ---------------------------------------- Finally, the user must provide a generic name that will be used to create the names of the output files. For instance, if the user provides: :: generic_name = 'C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-' Then the output files will have the following names (assuming that one moving object was selected): - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-01_check_images.txt - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-02_image_shifts.txt - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-03_selected_stars.pdf - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-04_inst_magnitudes.txt - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-05_best_diff_magnitudes_moving_object_1.txt - C:\\Desktop\\24Jan2010\\ProcessedImages\\Target-06_CDRCDLreport_moving_object_1.txt