A detection apparatus having a read head including a plurality of microfluorometers positioned to simultaneously acquire a plurality of the wide-field images in a common plane; and (b) a translation stage configured to move the read head along a substrate that is in the common plane. The substrate can be a flow cell that is included in a cartridge, the cartridge also including a housing for (i) a sample reservoir; (ii) a fluidic line between the sample reservoir and the flow cell; (iii) several reagent reservoirs in fluid communication with the flow cell, (iv) at least one valve configured to mediate fluid communication between the reservoirs and the flow cell; and (v) at least one pressure source configured to move liquids from the reservoirs to the flow cell. The detection apparatus and cartridge can be used together or independent of each other.