and four for MIRI MRS, corresponding to its four IFUs. The noise levels for representative synthetic observations (in this case, for a 10-hour integration on HAT-P-1) are shown in the bottom panel of Figure \[JWSTNoise\] in terms of the uncertainty in the observed transit depth in parts per million. Note that the NIRSpec Prism will observe fainter stars than HAT-P-1, but we have estimated the noise levels using a linear model, so they should be similar to those for longer integrations of fainter stars. The MIRI LRS Slit and Slitless modes are distinguished here, with the Slitless mode having lower noise levels because of its higher throughput. For much fainter objects, the noise level for the Slitless mode will be higher because the background from the sky will be relatively higher without a slit.

![image](hat-p-1b.noise.eps){width="99.00000%"}

NIRISS has one spectroscopic observing mode at medium resolution, the SOSS mode using the G700XD grating [@2012SPIE.8442E..2RD]. NIRCam has two modes at longer wavelengths, using the F322W2 and F444W filters and grisms, and the two instruments together efficiently cover the wavelength range from 0.6 to 5.0 $\mu m$ in three visits [@2007SPIE.6693E..0GG]. NIRISS and NIRCam are the best suited instruments for observing bright objects, with 