Instruments & Operations

 

 

News and Updates

Preparations for LUCIFER SDT (December 5-16, 2009)

Due by December 2nd for each project:

Please send this information to Dave Thompson.

Example LUCIFER data is available from mirrors in: [USA] [Germany] [Italy]

The LUCIFER User's Manual (.pdf.gz, 5.1MB, v1.0 20 Nov 2009)

LUCIFER SDT Publication Policy:

  1. Data obtained during SDT will be immediately available to all of the other SDT participants (across all partners) via the LBT data archive;
  2. All papers based on SDT data should be circulated to the SDT email list two weeks prior to submission;
  3. All SDT participants may be co-authors on any other papers based on SDT data if they request co-authorship. LUCIFER instrument team members, LBTO and SDT observers are encouraged to request co-authorship;
  4. Co-authors from outside the LBT partnership are allowed to request co-authorship if they contribute significantly to a specific paper, although LBT partners are to lead all papers. Such request should also be sent to the SDT mailing list by the project PI with a short justification, and be approved by the paper first author. Any dispute in authorship will be resolved by the LBTO director;
  5. All LBT papers should include the standard LBT credit line as described on the LBT Instrumentation webpage.

LUCIFER SDT (December 5-16, 2009)

Summary Description of LUCIFER

LUCIFER 1 and 2 are a pair of infrared multi-mode instruments for the Large Binocular Telescope. In seeing-limited mode, each will have a 4 arc-minute square field of view and will be capable of long-slit and multi-slit spectroscopy as well as imaging in the near infrared zJHK bands from 0.85 to 2.4 microns. Each instrument also includes diffraction-limited optics covering a 30-arcsecond field of view for use with the adaptive secondary mirrors. LUCIFER1 is now at the LBT and commissioning of the seeing-limited modes is nearing completion.

The LUCIFER team's webpage can be found here. On those pages can be found more detailed descriptions of the optical, mechanical, and electronic design.

Cameras (seeing-limited modes):

Filters:

LUCIFER1 Available Filters (October 2009)
Name
Center WL (microns)

FWHM (microns)

Trans (peak %)

Trans (avg %)
z
0.957
0.195
98.4
94.3
J
1.247
0.305
91.2
83.2
H
1.653
0.301
95.0
90.5
K
2.194
0.408
90.1
85.7
Ks
2.163
0.270
90.7
86.8
Br_gam
2.171
0.024
79.4
76.5
FeII
1.646
0.018
91.2
89.5
H2
2.137
0.023
87.9
84.9
HeI
1.086
0.015
65.2
64.6
J_high
1.301
0.108
95.9
93.3
J_low
1.197
0.112
95.4
93.3
OH_1060
1.063
0.009
68.6
66.8
OH_1190
1.191
0.010
80.4
78.0
P_beta
1.281
0.012
86.1
85.5
P_gam
1.095
0.010
81.1
80.0
Y1
1.005
0.069
67.3
64.2
Y2
1.072
0.065
94.2
89.5

Longslits:

Gratings:

The resolutions above are all derived using the N1.8 camera and an 0.5-arcsec (2-pixel) wide slit. Resolutions will double, and the wavelength range would be halved, if you use the N3.75 camera with an 0.25-arcsec (2-pixel for this camera) slit. This higher resolution spectroscopy mode has been commissioned, but spectrophotometric calibration is not complete.

The typical spectroscopic configuration will be with the 210 zJHK grating and the N1.8 camera, giving slightly less than a full single (z, J, H, or K) band across the detector. All of the gratings can be tilted over a small range so if your science requires a spectrum at the blue or red ends of the bandpass, this can be accommodated. The 200H+K grating alows for simultaneous H- and K-band spectroscopy. The 150Ks grating is blazed closer to the center of the Ks band and thus has a higher overall efficiency across the K band than the 210 zJHK grating.

Detector:

Guiding and Wavefront Sensing:

LUCIFER is connected to an Auto-Guiding and Wavefront sensing (AGw) unit. The AGw sensors are build onto an R-theta stage, the details of which are not critical at this point. But the guider does have a fixed patrol field with respect to the LUCIFER field of view and this must be considered when selecting guide stars and position angles for your observations. There are a few basic constraints to keep in mind:

    1. The guide probe can move on axis, but not past it
    2. The guide probe theta stage limits the X motion of the probe
    3. The focal plane is blocked at >330 arcsec radius
    4. There is vignetting from M3 at field angles above ~4.5 arcmin off axis
    5. To avoid vignetting LUCIFER, keep the probe >1 arcmin from the field edges

Some details:

1. The probe always appears to come down from above the LUCIFER field of view, independent of position angle on sky, because LUCIFER and the AGw are bolted together. Thus, you need to orient the observations such that a guide star is available in the patrol field.

2. The R-theta stage pivot point is 612 mm aove the center of the LUCIFER field. Limits at +/- 18 degrees restricts the motion to just inside the usable focal plane at the left-front bent Gregorian focus. So you need to be careful using guide stars at high field angles and position angles that put them near these limits.

3. The focal plane delivered by the telescope is blocked by parts of the AGw at field angles of more than 330 arcsec radius.

4. The tertiary mirror is a bit undersized and there is some vignetting visible in the wavefront sensor at high field angles (>4.5 arcmin). While the wavefront sensor has been adapted to account for this, selecting guide stars inside a radius of 240 arcsec from the science targert would be better.

5. The probe emits thermal radiation and appears bright in the K band, and at all wavelengths it shadows the LUCIFER entrance aperture when close to on axis. The apparent size of the probe is ~2 arcmin across, or about half the LUCIFER field of view. If this will cause problems for your project, you need to be careful in the selection of your guide star and the orientation of the field for your observations.

The AGw Patrol Field

AGw Patrol Field
A plot of the AGw guide probe patrol field (green) is shown at left, relative to the 4'x4' LUCIFER field of view (gray square) and the delivered focal plane at the left-front bent Gregorian focal station (outer 11 arcmin diameter circle). Click on the image for a full resolution jpeg, or you can download a PDF by clicking here.

During commissioning of the instrument and telescope, guide stars have been used with R-band magnitudes (e.g. "R2" mag from the USNO-B1 catalog) between 12.0 and 16.0. Much brighter than this saturates the guide camera and the system has not been calibrated or demonstrated to work at fainter magnitudes. We strongly recommend selecting guide stars within this range if possible, for maximum usability in varying conditions. However, fainter stars down to R~18.0 should work in good (<0.7 arcsec FWHM) seeing conditions.

Preparing for Observations with LUCIFER

Please follow the guidelines in the Call for Proposals and the User's Manual.

Operating LUCIFER

For SDT, LUCIFER will be operated in queue mode by the LBTO staff and a group of partner observers, with support from the LUCIFER Team.