LAICA
LAICA (Large Area Imager for Calar Alto) is a wide-field imager in the whole visible range, placed at the 3.5-m telescope prime focus.
With a field corrector, it covers a non contiguous field of view equivalent of 0.25 sq. degree with its four 4K CCDs representing each 15.5´x15.5´ on the sky, but spaced by gaps of 13.6 arcmin, since the CCDs are non buttable.
In four contiguous pointings, LAICA thus covers a full square degree field with slight overlap between CCDs to check the astrometry and photometry between pointings. These special and spatial characteristics make LAICA particularly efficient for survey observations, like the ALHAMBRA ones.
Available at: Primary focus (f/3.9) of the CAHA Zeiss 3.5-m telescope
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In a nutshell
| Instrument/Telescope | LAICA/3.5 prime focus |
| Field corrector | K3 three-lens (f/3.9) |
| Detectors |
Four BAE CCDs of 4096x4096 pixels |
| Field of view | 44.4'x44.4' (gaps 13.6') |
| Pixel scale | 0"225 / pixel (unbinned) |
| Read out time & noise |
80 s (unbinned) & 6e- |
| Intrinsic image quality | <0"3 |
| Geometrical distorsions | <2% (pincushion) |
| Wavelength range | UV atm. cutoff to 1 μm |
| Filter magazine |
20 bands, see filter list |
Observing with LAICA
| Preparing observations | During observations |
After observing |
| Requesting observing time | User's manual | Basic data reduction |
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Former webpage incl. the manual |
Basic troubleshooting | Alhambra pipeline TBC |
| CCD characteristics | Log sheets | Alhambra final data release |
| Exp. time calculator | Two guider CCDs (FT mode) |
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| QEs of CCDs #1, #2, #3 and #4 |
Shutter uniformity: 0.1% in 0.3s |
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| ZPs (Johnson bands) | ||
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Filters (incl. 20 medium-bands) |
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| Service mode observing template |
To center a target on e.g. CCD#1 (the one with the best cosmetic quality), in MIDAS use @@ center 1 |
More information
PublicationsReference article: MPIA newsletter Image gallery Spectacular images taken with LAICA, at times in combination with other CAHA facilities (see Vicent Peris and Fundación Descubre websites), including various NASA Astronomical Picture of the day: |
Calar Alto Press Releases
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History
LAICA construction started in 1999 by the following team head by the late Prof. J. W. Fried:
- Construction + mechanics: R.Rohloff, H.Baumeister, W.Benesch
- Electronics: B.Grimm, R.Klein, C.Unser
- CCDs: K.H.Marien
- TV-guiding: U.Graser
- Software: K.Zimmermann, F.Briegel
LAICA saw first light with test CCDs on 20 May 2001. Then it has been tested - with all CCDs working properly - on the telescope from October 2003, 24 to 27. Clouds prevented tests with star light. The CCD array looked very good, tests of linearity, dark current, shutter homogeneity etc. all gave excellent results. LAICA has been used in december 2003, and worked very well, including the auto guider. The Coma has been removed by alignment of the main telescope mirror.
