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Service observations with ISIS

  1. Introduction
  2. ISIS default settings
  3. Offered observing modes
  4. Calibrations


1. Introduction

ISIS offers a wide variety of observing setups, as it allows the user to choose the central wavelengths, slit width, dichroic, on-chip binning, etc. In order to minimize the time invested on setup changes and acquisition of calibration frames during service observations, the number of setups offered is limited. Nevertheless, non-default settings are allowed if their need is scientifically justified in the service application. Any corresponding additional overheads for the change of setup on sky, will be accounted to the requesting programme.

Having a large database of observations using a limited set of ISIS setups will also allow us to keep an optimal quality control of the instrument that will benefit users.

Imaging polarimetry, and observations requiring the QUCAM CCDs, are excluded from ISIS service observing, because of the higher cost and more limited opportunities to carry out such observations.

Spectropolarimetry observations, however, can be requested. They will be attempted whenever (1) a spectropolarimetry-trained observer is scheduled and (2) there is enough time to carry out the (extended) day-time set-up. The latter condition may not be satisfied e.g. on winter service nights (S, S/D) when ISIS has just been mounted on the telescope. The probability of completing spectropolarimetry proposals is therefore not as high as for normal ISIS service proposals.

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2. ISIS default settings

The following settings are the default for service observations:

  • Data will be obtained in slow read-out mode.
  • Detector window will be [585:1550,1:4200] in the blue arm and [555:1520,1:4200] in the red arm. The slit length, defined by these default windows, is 3.2 arcmin (blue) and 3.5 arcmin (red).
  • Default on-chip binning is 1x1 in both arms.
  • The 5300 Barr dichroic will be in place.
  • The GG495 order sorting filter will be in the red light path.
  • The Red+ and EEV12 CCDs for the red and blue arm, respectively, will be in use.
  • The standard central wavelengths are those listed in the available ISIS offered observing modes.
  • The default position angle of the slit is parallactic unless otherwise specified in the target list.

Exceptions to these default settings will be considered if justified in the service proposal.

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3. Offered observing modes

The two tables below list the gratings and central wavelengths offered during service nights, along with spectral dispersions and wavelength ranges. Notice that the response of the system+dichroic should also be taken into account (wavelength ranges in parentheses). 



ISIS red arm observing modes (with REDPLUS)
Grating
central
wavelength
Dispersion
(Å/mm)
Dispersion
(Å/pix)
Total Spectral
range (Å)
Unvignetted range
(2400 pixels)
50% unvignetted range
(3285 pixels)
R158R
7500
121
1.81
3735:11265 (5300:10000)
5294:9706 (5300:9706)
4481:10519 (5300:10000)
R316R
6450
62
0.93
4521:8379 (5300:8379)
5320:7580
4903:7997 (5300:7997)
R316R
8650
62
0.93
6721:10579 (6721:10000)
7520:9780
7103:10197 (7103:10000)
R600R
5900
33
0.49
4873:6927 (5300:6927)
5299:6501
5077:6723 (5300:6723)
R600R
7000
33
0.49
5973:8027
6399:7601
6177:7823
R600R
8200
33
0.49
7173:9227
7599:8801
7377:9023
R600R
9200
33
0.49
8173:10227 (8173:10000)
8599:9801
8377:10023
R1200R
5600
17
0.26
5072:6127 (5300:6127)
5291:5909
5177:6023 (5300:6023)
R1200R
6200
17
0.26
5672:6727
5891:6509
5777:6623
R1200R
6800
17
0.26
6272:7327
6491:7109
6377:7223
R1200R
7400
17
0.26
6872:7927
7091:7709
6977:7823
R1200R
8000
17
0.26
7472:8527
7691:8309
7577:8423
R1200R
8600
17
0.26
8072:9127
8291:8909
8177:9023
R1200R
9200
17
0.26
8672:9727
8891:9509
8777:9623
ISIS blue arm observing modes (with EEV12)
Grating
central
wavelength
Dispersion
(Å/mm)
Dispersion
(Å/pix)
Total Spectral
range (Å)
Unvignetted range
(2820 pixels)
50% unvignetted range
(3670 pixels)
R158B
4500
120
1.62
1182:7817 (3200:5300)
2216:6784 (3200:5300)
1528:7472 (3200:5300)
R300B
4500
64
0.86
2730:6269 (3200:5300)
3282:5718 (3282:5300)
2915:6085 (3200:5300)
R600B
4000
33
0.45
3087:4912 (3200:4912)
3372:4628
3182:4818 (3200:4818)
R600B
4500
33
0.45
3587:5412 (3587:5300)
3872:5128
3682:5318 (3682:5300)
R1200B
3600
17
0.23
3130:4070 (3200:4070)
3277:3923
3179:4021 (3200:4021)
R1200B
4250
17
0.23
3780:4720
3927:4573
3829:4671
R1200B
4900
17
0.23
4430:5370 (4430:5300)
4577:5223
4479:5321


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Basic calibrations (biases, tungsten flats and CuNeAr arcs) will be obtained by default in the afternoon/morning for each observing setup used during the service night. Other calibrations (flux standard, radial velocity standard, solar analogue stars, etc.) should be clearly described by the PI in the service proposal, who should also provide name, coordinates, finder chart, and any particular observing conditions. These extra calibrations, and any other calibrations (arcs, lamp flats) necessary to obtain while observing, will be charged to the total time requested.



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Contact:  (ISIS Instrument Specialist)
Last modified: 14 September 2016