Observer / Instrument Configurations

Instrument Configurations

General Rules

An instrument configuration should be specified as instrument_key1_key2_key3_...where the first keyword specifies the einstruments and the following keywords specify either optical elements or modes. Keywords should be separated by underscores and the configuration should have no spaces in it. In most cases the keywords consist of lower case letters and numbers, although there are a few exceptions where upper case letters are used.

The official, definitive description of instrument configurations is given on the HET resident astronomers' web page at http://het.as.utexas.edu/HET/hetweb/ProgramPrep/phaseII.html

LRS
for details see:	HET/LRS reference page and the HET Resident Astronomer Page
	Long-Slit Spectroscopy	Multi-Object Spectroscopy	Imaging
syntax	`LRS_grism_slit_filter`	`LRS_grism_mos_filter`	`LRS_no_no_filter`
keyword values: (case sensitive)	`grism = g1, g2, g3` `slit = 1.0, 1.5, 2.0, 3.0, 10.0` `filter = GG385, GG475, OG515, OG590, C` (`C`=clear)	`grism, filter` same as long-slit spectroscopy `mos` is a fixed kewyword	`no_no` means no grism and no slit (required keywords) `filter = B, V, R, I, C` (`C`=clear)

Notes about LRS syntax:

The slit size should be given in arcsec to one decimal place.
The filter names should include capital letters, e.g., GG485 not gg485. Note also that the BK7 filter is only used for engineering.

Examples:

LRS_g1_1.5_OG515 (spectroscopy with G1 grism, 1.5" slit, OG515 blocking filter)
LRS_no_no_B (imaging with B filter)

MRS
for details, see:	HET/MRS reference page and the HET Resident Astronomer Page
Syntax:	`MRS_Mode_Camera_Echelle_X-disperser_wave_fiber_skychop_filter_slit_mask_binning_filename`
keyword values (case sensitive)	`Mode = DF, LS, MOS` [currently, only "DF" is allowed] `Camera = Vis, JCAM, both` [currently only "Vis" is allowed] `Echelle = 79, 110` [currently only "79" is allowed] `X-disperser = 220, 600, 900, 1200` [currently only "220" is allowed] `wave = 7000` (central wavelength) [currently only "7000" is allowed] `fiber = 1.5Rs , 1.5Bs , 2.0R , 2.0B` `skychop` [positive integer required] `filter = 0` [must be "0" for "DF" mode] `slit = 0, 100, 200, 300, 600` [must be "0" for "DF" mode] `mask = 0, 5.0u, 15.0c, 3.0c , 5.5l` [must be "0" for "DF" mode] `binning = 1x1, 2x1, 1x2, 2x2 1x3,2x3, 1x4, 2x4, 1x5, 2x5` [currently only "2x2" allowed] `filename = none, <filename>` [currently only "none" allowed]

Some notes about MRS syntax:

Only a limited number of modes are availabe right now. More will be added later.

HRS
for details, see:	HET/HRS reference page and the HET Resident Astronomer Page
Syntax:	`HRS_ResPower_echelle_CrossDisp_fiber_skyfibers_slicer_gascell_binning`
Keyword values (case sensitive)	`ResPower = 15k, 30k, 60k, 120k` `echelle = blue, central, red` [use "central" for now] `CrossDisp cross disperser (316g or 600g) and central wavelength [use one of the values from the table below]` `fiber = 2as, 3as (as = arcsecond) skyfibers = 0sky, 1sky, 2sky [see note below] slicer = IS0 (0=zero, not the letter O), no image slicer gascell = GC0, GC1 (controls use of iodine gas cell: 0=do not use, 1=use) binning = 1x1, 1x2, 1x3, 1x4, 1x5, 2x1, 2x2, 2x3, 2x4, 2x5 [see notes below on recommended binning`

Possible Values of Cross Disperser Keyword
`CrossDisp`	Wavelength Range			Orders
`CrossDisp`	Begin	Central	End	Begin	Central	End
316g4931	3057	4931	6793	200	138	90
316g5936	4076	5936	7838	150	103	78
316g6948	5095	6948	8860	120	88	69
316g7940	6114	7940	9861	100	77	61
316g8991	7109	8991	10917	86	68	56
316g10022	8152	10022	11757	76	61	52
316g10917	9125	10917	12737	67	56	48
600g4739	3751	4739	5732	163	129	106
600g5271	4275	5271	6263	143	116	97
600g5822	4814	5822	6793	127	105	90
600g6302	5316	6302	7278	115	97	84
600g6869	5879	6869	7838	104	89	78
600g7366	6369	7366	8375	96	83	73
600g7940	6948	7940	8861	88	77	69
600g8375	7456	8375	9406	82	73	65
600g8990	7940	8990	9861	77	68	62
600g9405	8491	9405	10362	72	65	59

Notes about HRS setups:

The echelle keyword controls the echelle tilt angle for changing the blaze (central) wavelengths of the orders. Please use central until more information is distributed.
The maximum number of sky fibers that can be used without order overlap depends upon the values of CrossDisp and fiber. The limiting wavelengths are:
- 316g and 2as: 4000+ for 0sky, 5880+ for 2sky
- 316g and 3as: 4000+ for 0sky, 5880+ for 1sky, 7100+ for 2sky
- 600g and 2as: 4000+ for 0sky, 4200+ for 2sky
- 600g and 3as: 4000+ for 0sky, 4200+ for 1sky, 5100+ for 2sky
The format is (column binning)x(row binning), where column binning is in the cross dispersion dimension and row binning is in the echelle dispersion dimension. Typical binnings for each ResPower are

`ResPower`	Binning Scheme
`ResPower`	Possible Values	Recommended Values	Pixels per resol. element
`120k`	1x1, 2x1	2x1	2.0
`60k`	1x1, 1x2, 2x1, 2x2	2x1, 2x2	4.0, 2.0
`30k`	1x2, 2x2, 1x3, 2x3	2x3	2.7
`15k`	1x4, 2x4, 1x5, 2x5	2x5	3.2

The number of pixels per resolution element can be calculated as

pix = (240,000)/(Resolving power)/(row binning)

For example, with 2x3 binning and ResPower=30k (30,000), there are approximately 2.7 pixels per resolution element. Note that this value varies along the orders.
The width of the orders as a function of fiber is as follows
- for fiber = 2as: 13 pixels for row binning = 1
- for fiber = 3as: 20 pixels for row binning = 1

Examples:

HRS_15k_central_316g7940_2as_2sky_IS0_GC0_2x5
HRS_30k_central_600g5271_2as_2sky_IS0_GC0_2x3
HRS_60k_central_316g5936_3as_0sky_IS0_GC0_2x1
HRS_120k_central_316g6948_3as_0sky_IS0_GC0_1x1

Instrument Configurations

General Rules

Notes about LRS syntax:

Examples:

Some notes about MRS syntax:

Possible Values of Cross Disperser Keyword

Notes about HRS setups:

Examples: