Orion UltraBlock Narrowband Light Polution Filter

Hi there. You posted:

What targets do you use an OIII and 80mm on? Seems to me, like that
would be a little dim in most cases. Once I move to smaller scopes
(under 10) I generally prefer a UHC filter.

About the only thing I can think of off hand would be the Veil, and
even then I still prefer a UHC filter on a small scope.


Again, if used *with the correct magnification* the OIII is useful on a
variety of targets. M42 and M8 both show high contrast in the OIII at
13x, 25x, and 36x in my 80mm f/5, although the UHC shows a bit more
outer nebulosity under dark sky conditions. NGC 7293 (the Helix) is
best in the OIII, and the Rosette shows more contrast in the OIII than
it does in the UHC (21x), although the UHC shows a slightly larger area
of nebulosity. The large planetary NGC 1360 in Fornax is also higher in
contrast using the OIII. The Veil again is a bit better in the OIII
than the UHC, and while the North American is a bit fainter in the OIII,
the contrast is a bit higher in the OIII filter. I also prefer a little
more aperture for filter use (which is why I also have a 100mm f/6
refractor), but the "myth" that these filters are useless in smaller
apertures is one I like to dispell. For more detailed comparisons on
these objects with the various filters, check out the article "FILTER
PERFORMANCE COMPARISONS FOR SOME COMMON NEBULAE" on the Cloudynights web
page: http://www.cloudynights.com Clear skies to you.

--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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Howdy!

DAvid said:

On Wed, 16 Jul 2003 20:30:09 GMT, David Knisely
wrote:

Hi there. You posted:

What targets do you use an OIII and 80mm on? Seems to me, like that
would be a little dim in most cases. Once I move to smaller scopes
(under 10) I generally prefer a UHC filter.

About the only thing I can think of off hand would be the Veil, and
even then I still prefer a UHC filter on a small scope.


Again, if used *with the correct magnification* the OIII is useful on a
variety of targets. M42 and M8 both show high contrast in the OIII at
13x, 25x, and 36x in my 80mm f/5, although the UHC shows a bit more
outer nebulosity under dark sky conditions. NGC 7293 (the Helix) is
best in the OIII, and the Rosette shows more contrast in the OIII than
it does in the UHC (21x), although the UHC shows a slightly larger area
of nebulosity. The large planetary NGC 1360 in Fornax is also higher in
contrast using the OIII. The Veil again is a bit better in the OIII
than the UHC, and while the North American is a bit fainter in the OIII,
the contrast is a bit higher in the OIII filter. I also prefer a little
more aperture for filter use (which is why I also have a 100mm f/6
refractor), but the "myth" that these filters are useless in smaller
apertures is one I like to dispell. For more detailed comparisons on
these objects with the various filters, check out the article "FILTER
PERFORMANCE COMPARISONS FOR SOME COMMON NEBULAE" on the Cloudynights web
page: http://www.cloudynights.com Clear skies to you.


Thanks for the response (and the suggested targets). FWIW, I think
you mistake what I was saying. Perhaps I was unclear. I don't find
an OIII *useless* on small aperture - I just happen to find a UHC more
valuable.

I also find I prefer the UHC on the veil in small scopes.

YMMV, obviously.

And clear skies to you as well.

Tom T.

I ordered the filter yesterday, and it shipped out today. It is
estimated to arrive July 22nd, so I should be able to use it in some
dark skies if the weather permits. Thanks for all your help, I'll let
you know how it works when I get a chance to use it.

enterprise wrote:

Hello everyone, it's been quite a long time since I posted to this News
Group. I am planning on ordering Orion's UltraBlock Narrowband Light
Pollution Filter. Has anyone here ever used it? I've read that it
works quite well on objects it's made for (nebula). I was hoping
someone here could give me a firsthand account of how well it works.
Also, for a limited time, there is a special web sale going on that
lowers the price on this item to about $60, so I want to order as soon
as possible if it is indeed a worthwhile tool. Thanks

PS. As it's been a while, here are a few stats about me and my gear:

Orion XT8 8" Dob
Mag 5 to 5.5 skies on best nights, quite often lower.
Location: Sussex County NJ
Age of me: 22 as of Aug. 8
Website: http://users.nac.net/enterprise/astronomy/

For smaller apertures (6" and less), the Sirius Optics NEB-1 filter
does a *great* job -- more useful than the UB or UHC filters due to
its somewhat larger bandpass.

(Andrea Merritt) wrote in message om...
Hi!
In case you haven't read:
"Light Pollution Filters" by Dave Knisely at
http://www.weatherman.com/uhc.htm
It's an excellent summary!
In practice, 8" is what I would consider the minimum aperture for
effectiveness, on my 6" the vew was too dark to see enough contrast.
At 8" it is worthwhile, allows you to see detail that otherwise would
be missed, and you can see even more with averted vision using the
Ultrablock. For example, it brings out the nebulosity in M42 on the
edges. On the other hand, narrowband filters really shine on larger
apertures and from dark sky sites. I am an equipment geek and want
every edge possible - for me the filter is a must have. for $60, it's
a deal. Clear Skies! Andrea