The Caldwell Objects

and kinked. All this detail is wrapped in a faint
oval halo of light. At this power I see no welldefined
spiral arms. With 130x and excellent
seeing the northern clumps transform into a knot
and a ribbon of nebulosity that curls gently
eastward as part of the galaxy's feathery
The Caldwell Objects
67
inner spiral structure. A bright arc of light
defines the northeastern edge of the outer lens,
while an odd fuzzy patch to the southwest may
be a dust-disturbed part of the nuclear region. Or
is it a faint star?
On the evening of December 30, 1996, I
detected a very dim patch of light northwest of
the main galaxy at high power. It was in the right
position to have been NGC 1097A. But could I
have seen that magnitude-13.6 companion galaxy
in a 4-inch telescope? Quite possibly. Published
galaxy magnitudes in this range are suspect.
Christian Luginbuhl and Brian Skiff estimate
NGC 1097A's visual magnitude to be around
12.9, though I am certain it's probably a few
tenths of a magnitude brighter. Comet hunters
should note that the companion is not plotted on
the Millennium Star Atlas, but it is in Uranometria
2000.0.
NGC 1097 is yet another Caldwell object for
supernova hunters to keep an eye on. An HST
image of NGC 1097 taken on September 30, 1992,
captured Supernova 1992bd 12 days prior to its
ground-based discovery 2" east and 9" south of
the nucleus; the supernova shone at magnitude
15 at the time of ground-based discovery. More
recently, a magnitude-17.3 supernova appeared
23" east and 157" south of the galaxy's center in
November 1999.
269