This base SNAP survey will cover perhaps 15 square degrees at the ecliptic poles. By the end of base mission this region will be imaged to an AB magnitude of 30.4 in nine filters. The combined area here is about 6300 times larger than the planned ACS deep survey. No other planned instrument will provide this kind of deep survey. Every location in this region will be visited over 100 times in every band. So the same data set which will be combined to generate the deep survey provides a unique deep time domain survey as well.