Still intact, on November 21
ISON (C/2012 S1) swept into
this animated field of view (left) from the HI-1 camera on the
The camera has also captured
periodic Comet Encke, Mercury, and Earth,
with the Sun cropped out of the frame at the right, the source of
the billowing solar wind.
STEREO's perspective in interplanetary space,
planet Earth is actually
the most distant of the group, seen in its orbit beyond the Sun.
Mercury is closest, but both planets are still so bright they
create sharp vertical lines in the camera's detector.
Both comets clearly sport substantial tails,
but ISON is closer to
the camera and will continue to move more rapidly through the field.
Cameras on STEREO and SOHO spacecraft will be able to
Comet ISON as it falls towards its close encounter with
the Sun on November 28, even as ISON gets more
difficult to see
in the bright
dawn skies of planet Earth.