Offered Imaging modes

Imaging is offered with NaCo with a serie of broad and narrow (NB) band filters covering the range 1.0 to 5.0 μm. The complete list of filters and their characteristics is available.

For wavelength longer than 2.5 μm, chopping is not offered any longer. Mp imaging is therefore not possible.
For all other filters with wavelength longer than 2.5 μm obervations can be performed without chopping.

Starting P85 cube imagins is also offered in SM; more details can be found in the Users's manual.

As of p82 imaging is also ofered in combination with pupil tracking and cube mode.

Simultaneous Differential Imaging (SDI+) is also offered. SDI+ can be also combined with coronagraphy by means of a 4 quadrants phase mask (4QPM_H). SDI+ shows the same performance as the old SDI but with a larger FoV, 8x8 arcsec.

Typical magnitude limits with the NAOS visual dichroic

Band J H Ks L' M'
FWHM (mas) 32 42 56 98 123
Sky background (mag) 16.0 14.0 13.0 (1) 3.0 -0.5
Limiting magnitude (2) 24.05 24.05 23.35 18.55 15.15

(1): For the N90C10 dichroic, the background in Ks is 11 mag/square arcsecond
(2): 5 sigma in 1 hour using a V=11.5 mag. reference 10" away from the source with a visible seeing of 0.8".
These limits are valid for point sources (calculated over apertures of 1.25xFWHM radius). For NB filters, subtract 2 to 3 magnitudes.

Fabry Perot information

For technical reasons the Fabry-Perot mode will not be offered in P85.

SDI information

The SDI+ mode (SDI+) of CONICA obtains 4 images through 3narrow band filters simultaneously. Two images are taken outside the1.6 μm methane feature (at 1.575 and 1.60 μm) and two images are taken inside the feature (both at 1.625 μm). All filters have aFWHM of 25nm. The plate scale of the SDI+ camera is 17.32 mas/pixel.The FoV of each quadrant is 8x8 arcsec, even though this may be slightly smaller due to a tilt of the images.

Experienced SDI+ users advise to set the OFFSET dither box size to no more than 0.4x0.4" (enough to get rid of bad pixels).