It depends on your goals. I agree that the UHC is an excellent filter for
the most objects. But the UHC isn't the best filter for all. That's why I
don't like the score-keeping. It may lead one to draw the wrong conclusion.
The UHC, as well as all the other filters in the survey, were made by
Lumicon. But other manufacturers have similar filters. For example:
Lumicon has Deep Sky (relatively broad-band), UHC (narrower band, capturing
OIII and H-beta emissions), OIII (even narrower band, capturing both OIII
emissions), H-beta (line filter, centered around H-beta emission).
Orion has the corresponding SkyGlow, UltraBlock, and OIII filters (AFAIK no
H-beta).
Filters from other manufacturers employ similar strategies. But performance
of individual filters may vary depending on the width and location of each
passband.
It isn't surprising that the DGM NPB filter showed more detail on some
objects and more field stars than the OIII. The passband of the NPB is more
like the UHC filter. It would be interesting to compare the more versatile
UHC with the NPB on a variety of objects.
Albert
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Wow, I can really appreciate the work that went into that evaluation. The
UHC would seem the best choice. Who makes these?
-jg
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Before you run out to buy a filter, I suggest you talk to Mark about the DGM
filters he has. In side by side comparisons with an OIII filter, his DGM
usually shows more detail in nebulae AND more field stars. I don't know the
make-up of these filters.
Richard
Received on Wed Oct 12 21:49:45 2005