6.9.2.3 Option 3: No Peak-up

In some cases, it might not be strictly necessary to perform a peak-up and incur the requisite overhead time (although performing a peak-up is almost always recommended). The only obvious examples are an observation using the IRS Spectral Mapping mode (see Chapter 7 of this Cookbook) when the starting point within an extended region does not need to be precisely specified (to better than the nominal intrinsic pointing accuracy of Spitzer), or when the photometric calibration uncertainty associated with Low accuracy is sufficient, the target coordinates are well-known, and the observer does not need the set of peak-up images (see §6.9.2). However, the proposer should keep in mind that each pointing movement of the telescope introduces a cumulative, random positional error on the order of $0\hbox{$.\!\!^{\prime\prime}$}2$. Thus, spectral mapping observations using many steps and/or cycles can accumulate large pointing errors.