timeseries

timeseries goes through a set of frames and writes one table row per frame, usually to make a light curve.

Usage

munipack timeseries [options] file(s)

Each row holds the time of the exposure, any header values you ask for, and table columns (such as magnitudes) of the objects you choose. Run it on calibrated frames from phcal to get light curves, on APERPHOT or PSFPHOT tables for instrumental counts, or with no objects at all to follow airmass or other conditions through the night.

Objects are given by coordinates and matched to the nearest star in each frame. The time comes from DATE-OBS and EXPTIME; airmass and horizontal coordinates also need LONGITUD, LATITUDE and a WCS. If your camera uses other keyword names, set the environment variables FITS_KEY_DATEOBS, FITS_KEY_EXPTIME, FITS_KEY_LONGITUDE or FITS_KEY_LATITUDE.

Options

Objects

Option	Default	Description
-c, --coo “x,y x,y …”	—	Object coordinates, one pair per object, in one quoted argument (RA,Dec in degrees by default).
--cat file	—	Read the objects from a FITS catalogue instead (see Notes).
--coo-type DEG|RECT	DEG	Sky coordinates or pixel coordinates (see the warning below).
--coo-col col,col	RAJ2000,DEJ2000	Table columns to match against; use X,Y for pixels.
--tol value	from the frame	Match radius, in degrees or pixels (5 px for pixel coordinates).
--extname name	PHOTOMETRY	Table extension to read.

Warning

Leave out --coo-type for sky coordinates: an explicit --coo-type DEG finds no objects in this build. Use --coo-type RECT only for pixels.

What to list

Option	Default	Description
-l, --col col[,col,…]	—	Table columns to list for each object, e.g. MAG,MAGERR.
-K, --keys key[,key,…]	—	Header keywords to list for each frame, e.g. FILTER,AIRMASS.
--enable-filename	off	Add the file name.
--enable-horizon	off	Add azimuth and zenith distance of the field centre.
--enable-airmass	off	Add the airmass of the field centre.
--disable-timetype	off	Leave out the time column.

Time

Option	Default	Description
-T, --time-type JD|MJD|HJD|PHASE	JD	Kind of time in the time column.
--time-stamp MID|BEGIN|END	MID	Which moment of the exposure.
--lc-epoch JD	—	Reference epoch for the phase; without -T it switches to PHASE.
--lc-period days	1	Period for the phase.

Output and general

Option	Default	Description
-o, --output file	timeseries.fits	Output FITS table.
--stdout	off	Also print one line per frame on the terminal.
--verbose	off	Report objects or keywords missing in a frame.
-h, --help	—	Show the help.

Output

The table is in the first extension, so read it as 'timeseries.fits[1]'. Columns are named TIME, then the keywords, then <COL>_<n> for each listed column and object, e.g. MAG_1, MAGERR_1, MAG_2. An object not found in a frame gets 0 and a warning.

Examples

Light curves of two stars from calibrated frames:

munipack timeseries -c "180.00896,29.95754 179.98240,30.04617" \
    -l MAG,MAGERR -o lc.fits frame_*_cal.fits
munipack fits -lt 'lc.fits[1]'

Observing conditions through the night, no objects needed:

munipack timeseries -K FILTER,EXPTIME -T MJD --enable-filename \
    --enable-airmass --stdout -o night.fits frame_*.fits

Instrumental counts by pixel position, for aligned frames without astrometry:

munipack timeseries --extname APERPHOT --coo-type RECT --coo-col X,Y --tol 3 \
    -c "172.07,47.15 254.85,366.20" -l APCOUNT1,APCOUNTERR1 -o counts.fits frame_*.fits

Notes

• For accurate phases, list -T JD (or HJD) and fold the light curve yourself: --lc-epoch is stored with limited precision and gets rounded to a whole day.

• A catalogue for --cat is a FITS table with four columns, RAJ2000, DEJ2000 (deg), pmRA and pmDE (both in arcsec/year, or both in deg/day for Solar-system bodies). Zero proper motions are fine for most stars. Make one with fits --restore from a text file (see fits).