  Current understanding of the ammonia distribution in Jupiter's atmosphere is
provided by observations from major ground-based facilities and spacecraft, and
analyzed with sophisticated retrieval models that recover high fidelity
information, but are limited in spatial and temporal coverage. Here we show
that the ammonia abundance in Jupiter's upper troposphere, which tracks the
overturning atmospheric circulation, can be simply, but reliably determined
from continuum-divided ammonia and methane absorption-band images made with a
moderate-sized Schmidt-Cassegrain telescope (SCT). In 2020-21, Jupiter was
imaged in the 647-nm ammonia absorption band and adjacent continuum bands with
a 0.28-m SCT, demonstrating that the spatially-resolved ammonia optical depth
could be determined with such a telescope. In 2022-23, a 619 nm methane-band
filter was added to provide a constant reference against which to correct the
ammonia abundances (column-averaged mole fraction) for cloud opacity
variations. These 0.28-m SCT results are compared with observations from: a)
the MUSE instrument on ESO's Very Large Telescope (VLT) b) TEXES mid-infrared
spectrometer used on the NASA's InfraRed Telescope Facility (IRTF); and c) the
Gemini telescopes, and are shown to provide reliable maps of ammonia abundance.
Meridional and longitudinal features are examined, including the Equatorial
Zone (EZ) ammonia enhancement, the North Equatorial Belt (NEB) depletion,
depletion above the Great Red Spot (GRS), and longitudinal enhancements in the
northern EZ. This work demonstrates meaningful ammonia monitoring can be
achieved with small telescopes that can complement spacecraft and major
ground-based facility observations.
