The interstellar neutral (ISN) gas enters the heliosphere and is detected at
a few au from the Sun, as demonstrated by Ulysses and the nterstellar Boundary
Explorer (IBEX) missions. Ulysses observed ISN gas from different vantage
points in a polar orbit from 1994 to 2007, while IBEX has been observing in an
Earth orbit in a fixed direction relative to the Sun from 2009. McComas et al.
2018 reported about an IMAP-Lo detector on board the Interstellar Mapping and
Acceleration Probe (IMAP), with an ability to track the ISN flux in the sky. We
present observation geometries for ISN gas for a detector with the capability
to adjust the boresight direction along the Earth orbit over a year within a
multichoice ISN observation scheme. We study science opportunities from the
observations as a function of time during a year and the phase of solar
activity. We identify observation geometries and determine the observation
seasons separately for various ISN species and populations. We find that using
an adjustable viewing direction allows for ISN gas observations in the upwind
hemisphere, where the signal is not distorted by gravitational focusing, in
addition to the viewing of ISN species throughout the entire year. Moreover, we
demonstrate that with appropriately adjusted observation geometries, primary
and secondary populations can be fully separated. Additionally, we show that
atoms of ISN gas on indirect trajectories are accessible for detection, and we
present their impact on the study of the ionization rates for ISN species.
