A software package consists of an interferometric pattern simulator and characterizer, an optimized tiling generator and a beamforming weights calculator. This document only describes the package from version 1.0.0. Try Mosaic in your web browser here.
For python 3.8.5+
- numpy
- scipy
- matplotlib
- astropy
- nvector
- geographiclib
- katpoint
For python 2.7, A docker instance is recommended, the content of Dockerfile list below:
FROM ubuntu:16.04
MAINTAINER Weiwei Chen wchen@mpifr-bonn.mpg.de
RUN apt-get update && \
apt-get --no-install-recommends -y install \
wget python-pip python-setuptools python-wheel \
build-essential python-dev python-scipy python-numpy \
python-matplotlib python-astropy
RUN pip install 'nvector==0.7.0' 'pillow==4.0.0' WCSAxes geographiclib katpoint
Try Mosaic in your web browser here without installing anything.
To use offline, install the package via pip:
pip3 install https://github.com/wchenastro/Mosaic/archive/refs/heads/master.zip
There is a helper script example/maketiling.py to demonstrate the interface of the package
python3 ./maketiling.py --ants antenna.csv --freq 1.284e9 --source 00:24:05.67 -72:04:52.60 \
--datetime 2020.05.02 06:02:13.663903 --verbose --subarray 000, 001, 002:0.7, 003:0.5+0.1j \
--size 900 --resolution 40 --psf_plot psf.png --psf_fit psf.fits --weight
--ants: the file containing the antenna specification.
--freq: the frequency at which the interferometric pattern is simulated (Hz).
--source: the equatorial coordinates of the source in hh:mm:ss.s dd:mm:ss.s format.
--datetime: the date and time of the observation in UTC and in yyyy.mm.dd hh:mm:ss.s format.
--subarray: a list of index for selection of antennas in the file specified by --ants. Optional scale or complex weight can be attached after each antenna index separated by a colon.
--resolution: the scale of one single pixel in the pattern in arc seconds, default is None which means it is determined by the code.
--size: the total number of pixels in the simulation, default is 400 which corresponds to a pattern of 20x20 in dimension.
--field: the side length of the field of view in sexagesimal unit, such as 60s or 20m or 1d, default is None. --resolution, --size and --field can not be used all together, it can be combination of any two.
--psf_plot: filename of the plot of the pattern, the file format can be anything that matplotlib supports, such as "jpeg, pdf".
--psf_fits: filename of the fits file of the pattern
--weight: a switch for individual weight for each antenna, the weight values in --subarray will not be effective without this argument.
--verbose: print logs containing the input parameter and result, the input parameter listed in the log should reproduce the same result.
Example output:
python3 ./maketiling.py --ants antenna.csv --freq 1.284e9 --source 00:24:05.67 -72:04:52.60 \
--datetime 2020.05.02 06:02:13.663903 --beamnum 400 --verbose --overlap 0.7 \
--subarray 000, 017, 036, 038, 041, 043, 044 --tiling_method variable_size \
--tiling_shape circle --tiling_plot tiling.png --overlay_source overlay_sources
--beamnum: the requesting beam number in the tiling, the actual number in the generated tiling is less than or equal to this number. The default is 400.
--tiling_method: the method to use for generating the tiling, possible values are
- "
variable_size": given an overlap ratio, the code decide the size of the tiling - "
variable_ovelap": given a size of the tiling, the code decide the overlap between the beams.
--overlap: The beams in the tiling overlap with each other in their power levels equal to this ratio, only available in the "variable_size" method. The default is 0.5.
--tiling_shape: the shape of the tiling boundaries, possible values are: "circle", "hexagon", "ellipse", "polygon", "annulus". The "variable_size" method only supports the first two shapes.
--tiling_plot: the filename for the plot of the tiling, the file format can be anything that matplotlib supports, such as "jpeg, pdf".
--overlay_source: the file containing the point sources to overlay, one per line, in identification RA DEC format. for example: "C 00:23:50.3546 -72:04:31.5048"
Example output:
Generate an elliptical shape tiling, let the code decide a suitable overlap and output the coordinates
python3 ./maketiling.py --ants antenna.csv --freq 1.284e9 --source 00:24:05.67 -72:04:52.60 \
--datetime 2020.05.02 06:02:13.663903 --beamnum 400 --verbose --subarray 000, 001, 002, 003 \
--tiling_method variable_overlap --tiling_shape ellipse --tiling_parameter 0.07 0.05 45 \
--tiling_plot tiling.png --tiling_coordinate coordinate.csv
--tiling_coordinate: the filename for the equatorial coordinates in degrees.
--tiling_parameter_coordinate_type: the coordinate type of the parameter, default is image coordinate.
--tiling_parameter: the parameter of the tiling, for example:
- "
--tiling_shape circle --tiling_parameter 0.05": a circular shape tiling with radius of 0.05 degree - "
--tiling_shape hexagon --tiling_parameter 0.07 45": a hexagonal shape tiling with its circumradius and orientation in degrees - "
--tiling_shape ellipse --tiling_parameter 0.07 0.05 45": an elliptical shape tiling with its two semi-axis and orientation in degrees - "
--tiling_shape polygon --tiling_parameter 6.1522476, -72.0506681, 5.9448280, -72.0557907, 5.8695621, -72.0879815, 6.0670744, -72.1139826": a polygonal shape tiling with its vertices in "RA1, DEC1, RA2, DEC2, RA3, DEC3" format.
Generate a polygon shape tiling using a boundary region file and generate a region file for all the beams
python3 ./maketiling.py --ants antenna.csv --freq 1.284e9 --source 00:24:05.67 -72:04:52.60 \
--datetime 2020.05.02 06:02:13.663903 --beamnum 400 --verbose --overlap 0.7 \
--subarray 000, 001, 002, 003 --tiling_method variable_overlap --tiling_shape polygon \
--tiling_parameter_file polygon.reg --tiling_region tiling.reg
--tiling_parameter_file: the filename of the polygon boundary region file from ds9
--tiling_region: the filename for the region file of the generated tiling which can be imported into ds9
Example: