Sky & Telescope - May 2023 - 56

RON BRECHER (2)
MAY 2023 OBSERVING
Suburban Stargazer
CELESTIAL SURFBOARD M108 is nicknamed the Surfboard Galaxy
due to its elongated shape, a result of it lying not quite edge-on. Note the
irregular dust lanes cutting below center across the front of the galaxy,
which is very slightly inclined to our line of sight.
M97 is situated only a little more
than ¾° southeast of M108. But capturing
the Owl can be tricky because
of its pallid complexion. Identifying
it in my blanched city sky is a threestep
process. First, staying focused on
M108, I lower the magnification to
48×, then I shift the scope 23′ southeastward
to a 7.5-magnitude star (HD
97455). Finally, I veer southeastward
for another 23′ to the planetary.
Just one problem: I often sweep right
past the ghostly object. It may seem
counterintuitive, but the key to a quick
catch is to nudge s-l-o-w-l-y. There's a
6.6-magnitude star, HD 97302, shining
1
/3° southwest of M97. When I have
both HD 97455 and HD 97302 in the
low-power field, I know M97 is in there,
too. With that in mind, I add the LPR
filter, and a tiny, gauzy disk pops into
view. Bingo! I'm amazed at how a basic
LPR can lift M97 out of a city sky. An
Ultra-High Contrast (UHC) or doubly
ionized oxygen (O III) filter works even
better. The UHC and O III narrowband
filters block unwanted light from the
56 MAY 2023 * SKY & TELESCOPE
MIDNIGHT OWL M97 is a distended, atmospheric shell of gas ejected
from a dying, shriveling star. Bipolar outflows from the central star are
evident in this image, though the visual observer perceives only a diffuse
disk - perhaps with two dark " eyes " embedded within.
sky while passing most (though not all)
of the nebula's emission. The O III is
especially efficient. If you want the Owl
to hoot, give it oxygen!
Occasionally, I can make out M97
at 48× without a filter. As I increase
magnification, though, the round cloud
becomes terribly dim and diffuse. Much
beyond 100×, it dissolves into nothingness.
With the LPR in place at 127×, the
Owl becomes slightly oblate and vaguely
textured. The blotchiness gets me closer
to perceiving the two dusky hollows
in the disk. A UHC filter enhances the
nebula, but the field of view itself is a
bit darker. The O III view is darker still.
Amid the ambient neighborhood light, I
shield my eye in a bid to spy the eyes of
the Owl. One? Two? Maybe, just maybe.
Small-Scope Challenge
I asked my trusted colleague David
Rodger to give these disparate Dipper
objects a try. David lives in North
Vancouver, 100 km (62 mi) west of me.
He observes from a north-facing patio
and, like me, confronts a northern sky
he charitably characterizes as " almost
palatable. " David can detect M97 in his
4.7-inch apochromatic refractor at 39×
with the aid of an O III filter. His scope
doesn't show M108 at any magnification,
even with a LPR. David and I agree
that the slender galaxy is a tougher
challenge than the pale planetary.
It's fun trying to pick up M97 and
M108 in the same low-power eyepiece. I
can frame them in my 10-inch Dob on
opposite sides of a 58× field. I use a LPR
filter to enhance both the nebula and
the galaxy. (Be aware that while a UHC
or an O III will revive the planetary,
either one will kill the galaxy.)
I consider all this a victory. Glimpsing
these fragile deep-sky objects in a
city sky gives me a sense of satisfaction
- of winning against the odds. So,
get outside on the next clear, moonless
night and aim high!
¢ A few years ago, Contributing Editor
KEN HEWITT-WHITE actually heard an
owl hoot in the distance while observing
the Owl Nebula.
Sky & Telescope - May 2023

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