Spectroscopy exposure time estimates using:
VLT + FORS2
Keck + ESI
Gemini + GMOS
Subaru+FOCAS

Conditions:
Darkest sky.
Source: Black Body, T=11000K (restframe)
Slit: 1 arcsec
Airmass=1.2
Seeing=0.8
Binning 2x2
See instrument specifications below

Exposure time in seconds for a S/N ratio of 5-10:

VLT - FORS2: 

I mag	     Gr300V (z=0.5)	Gr300I (z=1)
23	     3000s (~0%)	   1h (10%)
24	     2.5h		   4h
24.5	     10h		   10h

Values in brackets: how longer the exposure should be in FORS1

GEMINI - GMOS: (This is very preliminary!!!)
I mag  GrB600(z=0.5)    GrR400 (z=1)
23     4h(?)		4h
24     20h(?)		20h(?)
24.5

---------------------------------------------------------------------------
Specifications VLT:
-------------------
 Wavelength Range     (Grism 300V)                 : 300.000 - 939.738 nm 
 Central Wavelength                                :      595.000 nm
or : Wavelength Range    (Grism 300I)              : 537.574 - 1100.000 nm 
     Central Wavelength                            :      870.000 nm
 Dispersion                                        :        0.336 nm/pixel
 Plate scale                                       :        0.250 "/pixel
 Probability of realisation of seeing              :       65.600 %
 Detector read-out noise level                     :        1.800 e-/pixel
 Detector dark current                             :   5.000e-/pixel/hour

Specifications Gemini:
----------------------
Gr B600 blaze:461nm R=1688 Covrge=276nm centered at 700nm
Gr R400 blaze:764nm R=1918 Covrge=416nm centered at 800nm