Instrument Performance

ThIS PAGE IS OBSOLETE! For up to date information see the ESO ETC!
It is kept only to maintain historic pre-2009 reccord of the instrument evolution and for reference.

Overheads

When estimating the total time required for a programme it is recommended to include about 3 min on average for each target acquisition and around 20-30% of the estimated integration time for instrument overheads. Larger overheads of up to 100% may be justified for programmes requiring many short integrations (imaging with DIT less than 2-3 sec) and/or complex target acquisition (e.g faint sources for spectroscopy in which case time should be allowed for first imaging the field and then offsetting the target into the slit).

The users are reccommended to creat sample obs with P2PP and to get the execution times from there.

Broad Band Limits

  1 minute 1 minute 1 hour 1 hour
Filter Continuum 

10-16erg.s-1.cm-2.A-1 

 Magnitude  Continuum 

10-16erg.s-1.cm-2.A-1 

 Magnitude
J (1.25) 1.4 x 10-2  20.7 2 x 10-3 22.9 
H (1.65) 1.9 x 10-2 19.7   2.4 x 10-3 21.9 
Ks (2.16) 1.2 x 10-2 18.7   1.6 x 10-3  20.9
Table 1. Measured point source detection limits for s/n =5 in a 1.5" diameter aperture (seeing: 0.75"). Sky brightness was J = 16 mag/sq arcsec, H = 14.3, Ks = 13.

Narrow Band Limits

   1 minute  1 minute  1 hour  1 hour
Filter  Continuum 

10-16erg.s-1.cm-2.A-1 

  Emission Line 

10-16erg.s-1.cm-2 

   Continuum 

10-16erg.s-1.cm-2.A-1 

 Emission Line 

10-16erg.cm-2.s-1 
1.083  6.3 x 10-2 9.3  8.1 x 10-3 1.2 
1.187  3.0 x 10-2 3.8  3.8 x 10-3 0.48 
1.215  7.5 x 10-2 14.5   9.5 x 10-3 1.9 
1.257  3.6 x 10-2 7.3  4.6 x 10-3 0.93 
1.282  7.4 x 10-2 15   9.5 x 10-3 1.9
1.644  6.3x 10-2 16.5   8.1 x 10-3 2.1
1.710
 6.3 x 10-2 17.3   8.1 x 10-3 2.2 
2.058  3.0 x 10-2 9.3  3.9 x 10-3 1.2 
2.090  3.1 x 10-2 7.0  4.0 x 10-3 0.9
2.122  2.9 x 10-2 9.3  3.8 x 10-3 1.2 
2.166  3.2 x 10-2 9.7   4.1 x 10-3 1.3
2.195  3.6 x 10-2 11.4   4.6 x 10-3 1.5 
2.280   3.1 x 10-2 10   4.0 x 10-3 1.3 
2.248  3.2 x 10-2 9.3   4.2 x 10-3 1.2 
2.336  3.8 x 10-2  12.4  4.9 x 10-3  1.6 
Table 2. Estimated point source detection limits for s/n =5 through narrow band filters.

Spectroscopic Limits

The sensitivity is a strong function of wavelength. For continuum sources, the sensitivity is plotted separately for the J, H and K atmospheric windows.

For emission line sources, the sensitivity is plotted separately for the J, H and K atmospheric windows.