Review of reduction steps needed on flux standard: (to reduce a standard telluric, see standard GMOS reduction page)
1. Find and prepare flux standard as described in Gemini Getfiles
2. prepare flats: GMOS Flats
3. prepare arcs: GMOS Arcs
4. gsreduce target
- see gsreduce.txt
5. gstransform target
- gstransform gsgsgtNfilename wavtran=gsgaNfilename
6. gsskysub tgsgsgsgt*
7. gsextract stgsgsgsgt*
8. gsstandard estgsgsgsgt*
- graphs=srei, sens.fits is the calibration spectrum
- Note: You may need to add points to constrain wobbles in the fit. Also watch the scatter in error. If it
has a pattern, try a higher order.
- Apply flux calibration to flux calibrator
- gscalibrate estgsgsgsgt*
GSSTANDARD parameters:
input = estgsgsgsgtS20070914S0117.fits Input image(s) sfile = std Output flux file (used by SENSFUNC) sfunctio= sens Output root sensitivity function image name (sci_ext= SCI) Name or number of science extension (key_air= AIRMASS) Header keyword for airmass (key_exp= EXPTIME) Header keyword for exposure time (fl_inte= yes) Run the task interactively (starnam= eg21) Standard star name(s) in calibration list (samesta= yes) Same star in all apertures (apertur= ) Aperture selection list (beamswi= no) Beam switch spectra (bandwid= INDEF) Bandpass width (bandsep= INDEF) Bandpass separation (fnuzero= 3.6800000000000E-20) Absolute flux zero point (caldir = home$caldir/) Directory containing calibration data (observa= Gemini-South) Observatory (mag = ) Magnitude of stars (magband= ) Magnitude types/bands (U|B|V|R|I|J|H|K|L|Lprime| (teff = ) Effective temperature of spectral types (ignorea= yes) Ignore apertures and make one sensitivity functi (extinct= ) Extinction file (out_ext= extinct.dat) Output revised extinction file (functio= spline3) Fitting function (order = 6) Order of fit (graphs = srei) Graphs per frame (marks = plus cross box) Data mark types (marks deleted added) (colors = 2 1 3 4) Colors (lines marks deleted added) (verbose= yes) Verbose? (logfile= ) Logfile name (status = 0) Exit status (0=good) (scanfil= ) For internal use only (mode = ql)