Echellette Suggested Calibrations
Pre-Reduction Setup
Initial Setup (Repeat for each night)
Tag | Type | Comment |
frame | 0 | FRAME Number |
flg_anly | 0 | Analysis flag 0=Don't Analyse, 2 = bias sub, 4=scatt |
Obj | ' ' | Object Name |
obj_id | 0L | Obj ID |
type | ' ' | ObjTyp : OBJ,STD,DRK,ZRO,IFLT,DFLT,ARC,MSK,IMG,TWI |
slit | 0. | Slit width |
exp | 0.d | Exposure time |
imfilt | ' ' | Image Filter : U,B,V,R,I, C |
mode | 0L | Mode: 0=Image, 1=LowD, 2=Echellette |
CCD | ' ' | CCD |
TEL | ' ' | Telescope |
namp | 0 | Number of Amps |
arclamp | 0 | Arc Lamps: (Binary flag) 1=CuAr, 2=Xe, 4=HgNe |
qtzlamp | 0 | QTZ Lamp: 0=off, 1=On |
rotmode | 0 | Rotation mode: 0=Stationary |
ccdspeed | ' ' | CCD Speed |
gain | 0. | Gain |
readno | 0. | Read Noise |
date | 0.0d | Date of Obs |
UT | ' ' | UT |
RA | ' ' | RA |
DEC | ' ' | DEC |
Equinox | 0. | EQUINOX |
refordr | 0L | Reference order (ECH only) |
rootpth | ' ' | Path of the Root |
img_root | ' ' | Root name (usually in Raw directory) |
flg_ov | 0 | OV FILE? 0=No, 1=Yes |
img_ov | ' ' | Name of OV file (with directory) |
flg_final | 0 | Final File? 0=No |
img_final | ' ' | Name of Final img |
ystrt | 0L | Column for initiating the trace |
arc_fil | ' ' | Name of the Arc image file (fits) |
map_fil | ' ' | Name of the Map image file (fits) |
flat_fil | ' ' | Name of the Flat image file (fits) |
obj_fil | ' ' | Name of object structure (fits) |
Example: IDL>
esi_editstrct, esi
Time : User interaction
Create Bias (Zero) frame
Pinhole Map
Process Flats (Steps 1,2)
Process Arc Image
This is the most important set of steps. The sky subtraction
algorithm will only succeed with a good Arc Image. It should be
emphasized that we only create one Arc Image per slit size and apply
this to all of the exposures taken with that slit size. The following
routines are well automated but should be checked carefully if you are
doing a 'final' reduction. I think it is possible that one could use
an Arc image from a previous run or the CALIBS database
but wouldn't recommend it just
yet. All of the following routines require a specific slit size.
Process Flats (Step 3)
Process the Standard
Process the Image
Tag | Type | Comment |
field | ' ' | Name of field |
slit_id | 0L | Used to store the order number (0-9) corresponding to physical order (15-6) |
obj_id | ' ' | ID value (a=primary, b-z=serendip, x=NG) |
flg_anly | 0 | 0=No analysis |
exp | 0. | |
xcen | 0L | Column where obj was id |
ycen | 0. | |
flg_aper | 0 | 0=boxcar |
aper | fltarr(2) | Widths of aperture, 0/1 = bottom/top (pixels) |
skyrms | 0. | RMS of sky fit |
trace | fltarr(5000) | |
npix | 0L | |
wave | fltarr(5000) | |
fx | fltarr(5000) | |
var | fltarr(5000) | ![]() |
flg_flux | 0 | 0=f![]() ![]() |
flux | fltarr(5000) | Fluxed data |
sig | fltarr(5000) | Err in fluxed data |
date | 0.0d | |
UT | ' ' | |
img_fil | ' ' | |
slit_fil | ' ' | |
instr_strct | ' ' | e.g. wfccdstr fits file |
Identify the Object
Sky Subtraction
Trace OBJ (yes, again)
Extraction
Combine Multiple Exposures (REQUIRED)
Flux the Spectra
Collapse to 1D
Continuum fitting and normalization
0. LWD Reduction
Create Bias (Zero) frame
LWD Setup :: esi_lwdsetup
Arc Image
Process Flats
Extract