This routine is a general purpose utility to list of selected data from FITS files, especially with calibration included. The most important instance of time-series are light curves.
munipack timeserie [...] file(s)
This utility is designed for listing of various quantities from a set of already processed frames to create of time-series. Both instrumental and calibrated data can be used. Full calibrated data including astrometry and photometry calibration are preferred.
By listing of a set of processed files, this tool creates a time dependence of a required quantity. The quantity is selected as a FITS-table column name and stored in a time series table. The time series of a light-like quantity is referenced as a light curve (LC).
The utility can be used to derive various kinds of times-like quantities.
The time can be specified for reference points:
Following types of time can be specified (Julian day on wiki):
Needs astrometry and photometry. To get calibrated fluxes or magnitudes, needs the photometry calibration.
On input, list of frames containing both astrometric and photometric information is expected.
On output, the FITS table representing the time series is created. All quantities can be also print on standard output.
This utility requires to identify both time and duration of exposures. By default, standard FITS keywords DATE-OBS and EXPTIME are used. They can be redefined with help of environment variables FITS_KEY_DATEOBS and FITS_KEY_EXPTIME.
There is also possibility to decode of times in legacy two-item format. In this case, date of form YY/MM/DD is included as FITS_KEY_DATEOBS while time HH:MM:SS is identified by keyword FITS_KEY_TIMEOBS which set to TIME-OBS by default.
Note. Some parameters (-l, -col, -c, -coo, -coocol) has been changed during Spring 2018.
By default, all stars on all frames are processed and stored to the output file. To select stars, there are two ways:
For a few stars request, the simpler way is specification of coordinates on the command line. Use twices of equatorial coordinates (Right Ascension and Declination) in degrees separated by commas (or semicolon). For example:
$ munipack timeseries -c "330.689,42.2765 330.667,42.2860" file.fits
More general way is use of a table with coordinates. Important advantages over command line:
The proper motion can be important for near and moving stars and should by used for flying rocks.
Format of the catalogue is very restrictive and must be carefully
followed. One is stored in FITS file with a just one table extension
(EXTNAME doesn't matter). The header must contain keyword EPOCH which
denotes the reference time t0 in Julian days for object coordinates.
The current positions at t are computed from reference coordinates
and proper motions μα0, μδ0 (in
degrees per century) as:
α = α0 + μα0 /(t - t0) / T
δ = δ0 + μδ0 /(t - t0) / T
where T is the time unit given by TUNITS keywords in header. One is one for deg/day and 365.25 for arcsec/year.
The most simple way how to create the catalogue, timeserie_cat.lst can be directly used as example and edited. The FITS file timeserie_cat.fits is created as
$ munipack fits --restore timeserie_cat.lst
|RAJ2000||Right ascension α0||degrees|
|pmRA||proper motion in RA μα0||arcsec/year or deg/day[†]|
|pmDE||proper motion in DE μδ0||arcsec/year or deg/day[†]|
This utility is primary indented and designed for working with low amount of data. The typical usage is listing of light curves or positions of motion of objects during a night. Another example can be study of any instrumental quantity. This routine is generic analysing tool.
Use on large archives of observations is not recommended. Spidering over a complicated directory structure would be really slow. To work with a large data archive, use Munipack to create tables with photometry and astrometry data and keep the results in a database. Much more better idea should be to import the data into some Virtual Observatory engine. Popular VO-engines are VO-Dance, Saada or GAVO DaCHS.
Light curve in magnitudes for stars at given coordinates listing all R-filter (by filename) files:
$ munipack timeseries -c "47.0422,40.9560 46.2941,38.8403" -l MAG,MAGERR 0716_*R.fits
Timeseries has been designed by format SimpleTimeseries (dead link) due J. Bloom which is abandoned now. Therefore the format of data is adapted for Munipack purposes and it should be changed in future.
Data format for timeseries, Light Curve Tutorial, Common options.