pyWise

Image reduction pipeline for the Wise Observatory.

Getting started

Prerequisites

• python 3.6 or above
• astropy
• configparser
• ccdproc
• numpy

Installing

Create and activate a conda environment with the necessary modules:

$ conda create -n wise astropy configparser ccdproc numpy python=3.7.1
$ source activate wise

Install the pyWise package:

$ pip install git+https://github.com/naamach/pywise.git

Upgrading

To upgrade pyWise run:

$ pip install git+https://github.com/naamach/pywise.git --upgrade

The configuration file

Finally, you will have to provide pyWise with the configuration file. To do so, you will need to have a config.ini file in the working directory (the directory from which you run the script). The file should look like that (see config.ini.example in the main directory):

; config.ini
[LOG]
PATH = /path/to/log/
CONSOLE_LEVEL = INFO ; DEBUG, INFO, WARNING, ERROR, CRITICAL
FILE_LEVEL = DEBUG ; DEBUG, INFO, WARNING, ERROR, CRITICAL

[GENERAL]
PATH = /path/to/images/
SAVE_UNCERTAINTY = False ; True - save uncertainty to FITS file
OVERWRITE = True ; True - overwrite previously-reduced frames
REDUCED_DIR = reduced ; reduced subfolder name

[CAL]
MAX_DAY_SHIFT = 14 ; maximal number of days away to look for missing calibration frames
PATH = /path/to/calibration_frames/  ; calibration frame archive
OVERWRITE = False ; True - overwrite previously-created master calibration frames
MIN_NUM_FRAMES = 5 ; minimal number of frames to combine (has to be an integer)
MAX_NUM_FRAMES = -1 ; maximal number of frames to combine (to solve memory problems; has to be an integer, -1 = unlimited)

[C28]
PATH = C28backup/ ; C28 subfolder name
DIR_SUFFIX = c28  ; nightly folder name suffix

[C18]
PATH = C18backup/ ; C18 subfolder name
DIR_SUFFIX = c18  ; nightly folder name suffix

Using pyWise

Copying the images

First, you need to download the images from mizpe-bck, and save them locally to the folder defined in the PATH parameter under GENERAL in the config.ini file. pyWise assumes a folder hierarchy similar to that of mizpe-bck, where there is a separate folder for each night for each telescope:

mizpe-bck
   |
   |-----20190531
   |-----20190601
   |
   |-----C18backup
            |
            |-----20190531c18
	    |-----20190601c18
   |
   |-----C28backup
            |
            |-----20190531c28
	    |-----20190601c28

You should copy the relevant nightly folder to your computer using a similar structure.

Directly from python

To reduce, for example, the images taken by the C28 telescope on 2019 May 29, run:

from pywise import wise
wise.reduce_night(2019, 5, 29, "C28")

or (note the "s" in reduce_nights!):

from pywise import wise
wise.reduce_nights("20190529", telescope="C28")

To reduce all the images taken by the C28 between 2019 May 29 and May 30, run:

from pywise import wise
wise.reduce_nights("20190529", "20190530", "C28")

Using the wise_reduce command

To reduce, for example, the images taken by the C28 telescope on 2019 May 29, run in the terminal, while the relevant python environment is activated:

$ wise_reduce -f 20190529 C28

This is assuming the config.ini file is in the current folder. Otherwise you can specify the path to the config file:

$ wise_reduce -f 20190529 -c /path/to/config.ini C28

To reduce all the images taken by the C28 between 2019 May 29 and May 30, run:

$ wise_reduce -f 20190529 -t 20190530 -c /path/to/config.ini C28

General usage:

usage: wise_reduce [-h] -f YYYYMMDD [-t YYYYMMDD] [-c config_file]
                   {1m,C28,C18}

Reduce Wise Observatory images.

positional arguments:
  {1m,C28,C18}          telescope

optional arguments:
  -h, --help            show this help message and exit
  -f YYYYMMDD, --from YYYYMMDD
                        date to reduce
  -t YYYYMMDD, --to YYYYMMDD
                        optional second date to define a date range to reduce
  -c config_file, --config config_file
                        path to config.ini file (default: config.ini)

Outline of pywise.wise.reduce_night

1. Get a list of images from the date and telescope requested (the path to the image folder is defined in the config.ini file).
2. Create master calibration frames (bias, dark, flat) for this night (if raw calibration frames exist), and save them to the calibration frame archive (defined in config.ini). The function takes into account the telescope, instrument, binning, subframe, and filter used.
3. For each science image, find the nearest available relevant calibration frames, subtract bias, subtract dark, and correct flat field.
4. Save the reduced image to the reduced image subfolder, in the format <object>_<JD>_<filter>_<telescope>.fits.

Notes

The FLI camera of the C28 telescope has a ~27s delay before each exposure in the "RBI flood" readout mode. As a result, the exposure actually starts 27s after the beginning of the exposure timestamp. pyWise corrects the JD keyword (and that keyword only) in the header of these images (and also in the JD that appears in the reduced image file name), to account for this delay (adding 27s to the original JD value). It then adds an RBIDELAY keyword with a value TRUE to the reduced image header.