NICER observation list: Target ID 869601

The NICER X-ray Timing Instrument is highly optimized for the study of X-ray pulsars, including millisecond pulsars (MSPs). MSPs form by accreting matter from a companion and spinning up to millisecond periods. Three sources, the ``transitional MSPs'' that transition between rotation-powered and accretion states, provide strong evidence for this formation scenario. These sources are part of the ``redback'' MSP class when in the rotation-powered state. In their subluminous disk state, their rotation-powered pulsations cease, but X-ray pulsations can instead be observed. We propose to search for X-ray pulsations in two transitional MSP candidates using NICER, in order to confirm their neutron star nature and as a first step toward longer-term timing observations.