For the smaller planetaries, I believe an OIII filter is the better choice,
but the UHC can do wonders at knocking back the light pollution and drawing
out emission nebula such as the Lagoon, the Trifid, the Swan, and even The
Great Nebula in Orion in Winter. I've never had a lot of luck with detail in
The Eagle Nebula, other than seeing a ghost of whispy illumination, but
still the difference with and without is pretty striking. Definitely worth
the cost of admission in my opinion.

My zenith is around magnitude 5.5 on any decent cloudless night, and can
reach 5.7 depending on the transparency and seeing. Down on the south
horizon where the best of the summer nebula can be found, the sky quickly
dives down to around magnitude 4. This is where the filter really helps me
out with the aforementioned nebula.

I made a run at the summer planetaries a few nights ago and found the UHC to
be only a marginal help on the smaller, brighter ones. The UHC really seems
to pay off in pulling out the larger diffuse nebula. Whether planetary or
emission. That includes the Owl Nebula as well. Any that are dim and
somewhat large compared to the several smaller planetaries.

YMMV
-Stephen


"kowen" wrote in message
m...
Florian,

I found your post interesting.
I live out in the country, no city light pollution, but do have a
streetlight- 350 ft to the east, a closer flood on top of a post-about
65 ft. east, and a neighbor's backyard flood, about 500 ft N/NE.

I think the area West-North is my best hope for seeing, as there is an
empty field behind my house (west) and a pasture behind my neighbor's
house (north) that goes far to the west. I have seen the 12-Gamma-1
Delphini star, naked eye, 5.15 mag in Delphinius, when seeing allowed.

If my average mag skies are 4.3 (Zeta Lyrae) or perhaps a little
better, might I benefit from a UHC filter? I'm thinking about getting
one of these-an Astronomiks, but have read ultimately they work best
at dark sky sites-not hard to believe. I do get those few rare
evenings where it seems there is sugar sprinkled on black velvet-nice,
steady, clear nights. Can you tell me what mag skies are in your
area?

Another example, I can see the three main stars of the Triangulum
(4.03 Gamma Trianguli)on a regular night, even thought that area of
the sky has the streetlight, and one much further NE up the highway.
Of course, through binoculars or the scope I can see the "invisible"
higher mag stars.

I have Orion's XT4.5, 3 years the end of this October-a keeper, good
grab & go-no Televue refractor here-and with the Skyquest Classics
going on sale, have the XT8 on the way (talk about new scope
curse...). I found M57 a few weeks ago-I've been lagging on finding
objects-so I'm spurred on to find more. Any insight into this would
be appreciated.

Clear skies,
Kerry
s.e. Louisiana