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The second method is a somewhat subjective recommendation for the best
filter to use on the given object, based mainly on a personal judgement,
and thus is more a matter of opinion and taste. The nebular brightness,
total area shown, contrast of details, and overall view are all weighted
to give an opinion of which filter will work well for which object. Other
observers would doubtless have somewhat differing views on recommendations
for the specific objects which were observed. When objects were best seen
in two filters (ie: nearly equal or beneficial performance), both filters
would be given the recommendation for the object, with the one yielding
the better overall view being listed first and the "close second" best
listed next to it.
Recommendation Ranking Summary
UHC
best on 34 nebulae, close second best on 39 nebulae.
TOTAL 1st and
2nd RECOMMENDATIONS for UHC: 73 objects.
OIII
best on 32 nebulae (biased by the inclusion of some planetary nebulae),
close second best on 19 nebulae. NOT recommended on 7 nebulae. TOTAL 1st
and 2nd RECOMMENDATIONS for (OIII): 51 objects.
DEEP-SKY
best on 7 nebulae, second best on 2 nebulae.
Provided at least some
slight improvement for all nebulae surveyed.
TOTAL 1st and 2nd
RECOMMENDATIONS for DEEP-SKY: 9 objects.
H-BETA
best on 10 nebulae, second best on 2 nebulae.
NOT recommended on 36
nebulae!
TOTAL 1st and 2nd RECOMMENDATIONS for H-Beta: 12
objects.
General Trends in Results
So far (with a few notable exceptions), the numbers show the UHC and
OIII are the filters of choice for viewing nebulae, and to some degree
supports the general recommendation that if only one filter can be
purchased, it should be the UHC. In performance characteristics, the UHC
filter tends to reveal a slightly larger and/or brighter area of
nebulosity with many emission nebulae than the OIII does, while the OIII
filter will often yield somewhat more contrast and dark detail on a given
object. The OIII also tended to be a bit better for "blinking" small
planetary nebulae than the UHC was, while the H-beta often hurt the view
of many planetaries. The inclusion of some planetary nebulae may have
slightly inflated the score of the OIII filter, since in general, the OIII
often does a bit better on those objects. The H-Beta tended to be most
useful on a more limited number of objects (about 15 % of the 81 objects
surveyed) than either the UHC or the OIII filters. This may be due at
least in part to the fact that many of the so-called "H-beta objects", are
low exitation very faint nebulae, and thus are near or beyond the visual
limits of my ten inch. The Deep-Sky filter almost always produced at least
some gain in contrast for nearly every object observed (especially when
some skyglow was present), but rarely produced a spectacular improvement
of the view. Filter comparison results for each of the objects observed
are shown below.
-------------------------- SPECIFIC OBJECT RESULTS
---------------------------
Each object is listed with the various filters. Each filter's numerical
score (0, 1, 2, 3, 4, 5; see earlier comments) is given, followed by the
overall filter recommendation for the specific object. In the
RECOMMENDATIONS portion, a "/" between the two filters named indicates
that both filters will work well on the object, with the one on the left
side of the slash being a slightly better choice: ie: "UHC/OIII" means the
UHC is slightly better overall, but the OIII will be quite useful as well.
M1 CRAB NEBULA (SNR in Taurus)
DEEP-SKY: (3) Improves the contrast
and brings out the wispy arc-like cusp on the eastern end.
UHC: (4)
Darkens the background and reveals little hints of tattered detail on the
edges with the eastern "cusp" now more visible.
OIII: (3) Much darker
than in UHC, and appears slightly smaller and somewhat rounder, but with
hints of filamentary detail on the edges and across the nebula at moderate
powers.
H-BETA: (0) barely visible.
RECOMMENDATION FOR M1:
UHC/DEEP-SKY (H-beta not recommended).
M8 LAGOON NEBULA (diffuse Nebula in Sagittarius).
DEEP-SKY: (3)
Some increase in contrast, with a bit more nebulosity visible than without
a filter.
UHC: (5) Large boost in contrast and visiblity of outer
nebulosity. Nebula appears much larger (nearly a degree wide) with some
detail enhancement, especially in the outer regions.
OIII: (5) Slightly
fainter than in the UHC, but shows slightly more contrast and dark detail
than UHC does. Some of the outermost nebulosity fades, but detail in inner
regions is remarkable. Faint red color can be noted in the brighter areas.
May be the better filter under light polluted conditions. H-BETA: (2) Dims
the nebula considerably, with only the circular ball of haze around the
Hourglass nebula and the external arc being easy to see.
RECOMMENDATION FOR M8: UHC/OIII
M16 EAGLE NEBULA (diffuse nebula in Serpens).
DEEP SKY: (2) Faint
diffuse nebulosity is slightly easier to see than without a filter. Not a
great deal of detail visible in nebula.
UHC: (4) Large increase in
visible nebulosity, showing wide diffuse fan of light in the shape of a
broad "T". Small darker inclusion becomes visible along the northern
side.
OIII: (4) Slightly fainter than with UHC, with slightly less
faint outer nebulosity, but shows more contrast and dark detail in the
interior, including faint narrow "fingers" from south side into the center
of the nebula with averted vision.
H-BETA: (2) Dims the nebula
significantly, but "T" shape still vaguely visible.
RECOMMENDATION FOR
M16: UHC/OIII, but H-BETA hurts the view.
M17 SWAN (OMEGA) NEBULA (diffuse nebula in Sagittarius). DEEP-SKY: (3)
Some improvement in contrast and detail, with the fainter loop of
nebulosity to the northeast just becoming visible to form the omega
shape.
UHC: (4) Noticable improvement in contrast and detail, with much
of the faint nebulosity on the outer regions and along the "omega" loop
becoming quite easy to see.
OIII: (5) Slightly fainter than UHC, but
contrast is also higher, with a rather striking dark area becoming
noticable along the west side of the swan's neck. Dark detail in interior
of main bar is better defined than with UHC. H-BETA: (1) Object is
noticably dimmed compared to the other filters, making the filter a poor
choice for use on M17.
RECOMMENDATION FOR M17: OIII/UHC (H-BETA not
recommended).
M20 TRIFID NEBULA (diffuse emission/reflection nebula in Sagittarius)
DEEP-SKY: (2) Small difference between filtered and unfiltered views with
a slight gain in contrast with the filter, but with any light pollution,
the filter may be of greater use.
UHC: (4) Nebula is slightly fainter
than with DEEP-SKY filter, with a slight gain in contrast over the
DEEP-SKY and more contrast gain over unfiltered views.
OIII: (3) Nebula
is fainter than with UHC or DEEP-SKY, and main trifid section appears
slightly smaller (hurts the northern reflection nebulosity), but dark
detail in the inner "lanes" shows up slightly better.
H-BETA: (4)
Nebula is somewhat fainter than in UHC, but trifid section shows a bit
larger area of nebulosity than the UHC does. It kills the reflection
nebula and reduces the brightness of the detail right around the central
star.
RECOMMENDATION FOR M20: UHC/H-BETA.
M27 DUMBELL NEBULA (planetary nebula in Vulpecula) DEEP-SKY: (3) Some
improvement in visibility of outer haze off the sides of the dumbell, but
the object is also slightly fainter.
UHC: (5) Large improvement in
contrast and outer detail, with large "wings" of light off the Dumbell's
sides becoming easy to see. Interior seems brighter and bigger, with
interesting greenish glow.
OIII: (4) Dimmer than with UHC, but interior
shows more dark detail and contrast. "Wings" off the sides remain fairly
easy to see.
H-BETA: (1) Nebula is dimmed greatly by the filter,
extinguishing the fine outer detail and only showing the inner
dumbell-shape.
RECOMMENDATIONS FOR M27: UHC (OIII also useful in
showing some inner detail, but H-BETA is NOT recommended).
M42 GREAT ORION NEBULA (diffuse nebula)
DEEP-SKY: (3) A moderate
boost in contrast can be seen, and much more outlying nebulosity is
visible. This is a good filter for the general public, since it still will
show the stars while enhancing the nebula. UHC: (5) Large boost in
contrast over no filter is noted. Outer nebulosity is quite easy to see,
with southward loop being easily seen with averted vision. Bluish and
greenish colors are quite easy to note with direct vision. OIII: (4) A few
of the outermost nebulosity areas are dimmed, but there is more contrast,
with considerable improvement in light and dark detail, especially in the
inner regions. Bluish and occasionally, reddish tints are noted with large
apertures. M43 is somewhat fainter than in the UHC filter, but narrow
bandwidth of OIII may make it the filter of choice with light
pollution.
H-BETA: (3) Much of the fainter outer areas of the nebula
vanish, but fan-like main portion and M43 remain, with interesting
contrast and changes in detail visible, including a brighter linear arc in
the western part of the fan. Some reddish hints are also visible in the
H-beta.
RECOMMENDATION FOR M42: UHC/OIII (near-tie)***
M43 (north part of Great Orion Nebula).
DEEP-SKY: (3) higher
contrast than without filter, but not much detail enhancement except when
there is some light pollution.
UHC: (3) somewhat more contrast than
with the Deep-Sky with overall "comma" shape now easily seen.
OIII: (2)
dims the nebula, but overall shape is still easily visible. H-BETA: (4)
Really makes M43 stand out, with high contrast and some irregular dark
detail in the overall comma-shaped nebula.
RECOMMENDATION FOR M43:
H-BETA (UHC and Deep-Sky also help).
M57 RING NEBULA (planetary nebula in Lyra)
DEEP-SKY: (2) Darkens the
background slightly, and brings out hints of very faint nebulosity off the
ends of the oval, but otherwise doesn't help much.
UHC: (4) Really
darkens the background and stars, and begins to show a more prominent glow
in the interior of the ring, with hints of faint outer nebulosity around
the outer edges of the ring.
OIII: (4) Darkens the nebula and the
background still further, but slight increase in contrast noted. Outer
shell just visible with averted vision. H-BETA: (0) Really kills things,
with the nebula now being very dim. RECOMMENDATIONS FOR M57: UHC/OIII.
Nebula is bright and small enough not to really benefit enormously from
filter use, but UHC does improve it to a degree (H-BETA is NOT
recommended!).
M76 "MINI-DUMBELL" or BUTTERFLY NEBULA (planetary nebula in
Perseus):
DEEP-SKY: (2) Marginal improvement over no filter, with hints
of nebulosity off the sides of the dumbell.
UHC: (4) Much more
nebulosity visible, including faint patches or "wings" off each side of
the dumbell, along with some interior detail.
OIII: (4) Nebula is
slightly fainter, but shows more contrast, with some dark detail being
seen near each lobe of the dumbell. The patches off to the sides of the
dumbell look like partial loops.
H-BETA: (0) Dims the nebula almost to
extinction at moderate powers.
RECOMMENDATION FOR M76: OIII/UHC (H-BETA
NOT recommended!).
M97 "OWL NEBULA" (planetary nebula in Ursa Major):
DEEP-SKY: (2)
Slight improvement over non-filter use (hints of the "eyes"). UHC: (4)
Much higher contrast than with Deep-Sky filter. One eye and hints of the
other are seen.
OIII: (5) Increase in contrast over UHC. Both eyes
visible with hints of irregular outer edge structure.
H-BETA: (0)
Nearly obliterates the nebula.
RECOMMENDATION FOR M97: OIII/UHC (H-beta
not recommended).
NGC 40 (Planetary Nebula in Cepheus):
DEEP-SKY: (3) Slight increase
in contrast and detail (brighter opposing sides), but object does not
really require a filter.
UHC: (3) Slightly fainter than in Deep-sky,
but shows a bit more contrast.
OIII: (2) Somewhat fainter than in UHC,
but disk still quite visible. H-BETA: (2) Somewhat fainter than in UHC,
but very slightly brighter than with the OIII filter (a "near" H-beta
object).
RECOMMENDATION FOR NGC 40: DEEP-SKY/UHC (near tie).
NGC 246 (Planetary in Cetus):
DEEP-SKY: (2) defines it a bit better
than without a filter, but still mainly a diffuse roughly circular glow
around a few stars.
UHC: (3) Higher contrast, with nebula now a fairly
well-defined moderate-sized dim disk with hints of brightness variations
in the interior.
OIII: (5) Dramatic increase in contrast over the UHC!
Shows several dark spots in the interior and hints of sharp filament-like
outer edge of the disk. H-BETA: (0) Really kills the nebula (barely
visible).
RECOMMENDATION FOR NGC 246: OIII. (H-Beta not
recommended).
NGC 281 (Diffuse emission nebula (Cassiopeia):
DEEP-SKY: (3) Nebula
is somewhat easier to see (barely visible without filters), with the edges
being more defined.
UHC: (4) Noticable improvement in contrast and
detail, appearing larger than with Deep-Sky filter, and containing some
dark detail.
OIII: (4) Nebula is dimmer, but interior dark lane-like
detail becomes more noticable, and the overall nebula shape is better
defined than in UHC. H-BETA: (2) Dims the nebula much more than OIII, with
no more detail than is seen with the Deep-Sky filter
(dim).
RECOMMENDATIONS FOR NGC 281: UHC/OIII.
NGC 604 (HII region in galaxy M33 in Triangulum).
DEEP-SKY: (2)
slight increase in contrast over unfiltered view, but easy to see without
filters.
UHC: (3) Much easier to see than in Deep-sky, standing out
well as an oval puff, with much of the detail in the galaxy remaining
visible. OIII: (4) Considerable increase in contrast, almost "blinking"
over UHC and unfiltered views. Galaxy is much fainter, but nebula really
stands out. H-BETA: (2) Much dimmer than in the other filters, but nebula
is still seen.
RECOMMENDATION FOR NGC 604: OIII/UHC.
NGC 896/IC 1795 (diffuse nebula in Cassiopeia).
DEEP-SKY: (3)
noticable increase in visiblity, with nebula being only a glow without the
filter. Two areas of dim diffuse nebulosity seen, one large (IC 1795) and
the other smaller (NGC 896).
UHC: (4) Much more prominent, with better
definition and a little dark detail, along with a wispy outer arc curving
around from south part of IC 1795. OIII: (4) Dimmer than in UHC, but more
dark detail visible with faint outer loop-like structure visible arcing
south, almost connecting the two patches. H-BETA: (1) Barely
visible.
RECOMMENDATION FOR NGC 896/IC 1795: UHC/OIII (H-beta not
recommended).
NGC 1360 (large Planetary Nebula in Fornax).
DEEP-SKY: (2) slight
increase in contrast with nebula easier to see than without a filter (but
still visible without a filter).
UHC: (4) Significant improvement in
contrast, with nebula appearing larger and noticably oval. Some irregular
interior detail and central star noted. OIII: (4) Even more contrast than
UHC, with clear interior arc-like detail, but central star much fainter.
Nice dark background H-BETA: (0) Kills the nebulosity with only the
central star and a small hint of haze around the star being
visible.
RECOMMENDATION FOR NGC 1360: OIII/UHC (H-beta not
recommended).
NGC 1499 CALIFORNIA NEBULA (diffuse Nebula in Perseus). Without
filters, the nebula is barely visible as a faint brightening of the field
with no detail.
DEEP-SKY: (2) A slight increase in contrast was noted,
but otherwise, the view was similar to that without a filter.
UHC: (2)
Slight increase in contrast over the Deep-Sky filter, making the edges of
the nebula slightly easier to see, but nebula is still somewhat difficult.
Hints of vague brightness variations across the object are noted. OIII:
(1) Nebulosity is quite dim in a very dark field.
H-BETA: (4) Dramatic
increase in contrast noted, making the object fairly easy to notice, with
well-defined borders. Some faint filamentary detail is also noted.
California Nebula is visible to unaided eye when H-beta is used.
RECOMMENDATION FOR CALIFORNIA NEBULA: H-BETA.
NGC 1514 "CRYSTAL-BALL NEBULA" (planetary nebula in Taurus):
DEEP-SKY: (2) Nice faint round puff around a faint star, easier to see
than without a filter.
UHC: (4) Significant improvement in contrast,
well-defined hazy ball with hints of dark detail in the interior of the
nebula.
OIII: (4) More contrast than in UHC, with dark detail and
arc-like forms in the main shell. Dimmer than in UHC but a bit better
overall. H-BETA: (0) Almost wipes out the nebula.
RECOMMENDATION FOR
NGC 1514: OIII/UHC (H-Beta NOT recommended).
NGC 1999 (diffuse nebula in Orion):
DEEP-SKY: (2) slight
enhancement over no filter, and easy without one.
UHC: (1) fainter than
Deep-Sky or no filter.
OIII: (1) fainter than UHC or
Deep-Sky.
H-Beta: (1) fainter than Deep-Sky, UHC, or no
filter.
RECOMMENDATION FOR NGC 1999: DEEP-SKY
NGC 2022 (planetary nebula in Orion):
DEEP-SKY: (3) visible without
a filter, but stands out better with Deep-sky (small fuzzy disk).
UHC:
(4) Noticably improves the contrast, with an almost annular form visible
at higher magnifications.
OIII: (5) Much higher contrast and darker
background than in UHC, but UHC or no filter may be bit better for high
power observations of details. H-BETA: (0) Almost wipes it out (barely
visible).
RECOMMENDATION FOR NGC 2022: OIII/UHC (H-Beta NOT
recommended).
NGC 2024 "FLAME NEBULA" (diffuse emission/reflection nebula in Orion)
DEEP-SKY: (3) Noticably improves the contrast with the dark lane-like
detail visible.
UHC: (3) Darker than in Deep-sky but with only a slight
increase in contrast.
OIII: (2) Darker than in UHC, with less detail
than in UHC. H-BETA: (1) Darkest of all three filters, but the nebula
remains visible with detail similar to that of OIII.
RECOMMENDATION FOR
NGC 2024: DEEP-SKY/UHC (near tie).
NGC 2174 (diffuse nebula in northern Orion).
DEEP-SKY: (2) very
faint glow around a single star with hints of detail (much easier to see
than without a filter).
UHC: (4) Large increase in contrast over
Deep-Sky filter, showing a large circular area of haze with vague
irregular interior dark detail. OIII: (4) Dimmer than in UHC, but has more
contrast, showing some dim lane-like structure.
H-BETA: (0) Dims the
nebula almost to extinction, showing less than the
Deep-Sky.
RECOMMENDATION FOR NGC 2174: UHC/OIII (near tie) (H-Beta NOT
recommended).
NGC 2327 (diffuse nebula in Monoceros).
DEEP-SKY: (2) Very faint
diffuse roughly circular haze around 7th mag. star.
UHC: (3): Object is
larger with slightly better definition than in Deep-sky.
OIII: (2):
nebula is now very faint, with only the area round the star visible.
H-BETA: (4): object is not quite as bright as in UHC but is much better
defined, showing a dark inclusion from the northeast and a brighter
arc-like western edge.
RECOMMENDATION FOR NGC 2327: H-BETA/UHC
NGC 2237-9 "ROSETTE NEBULA" (diffuse nebula in Monoceros). DEEP-SKY:
(2) Some increase in contrast, but nebula is still more of a diffuse haze
around the central star cluster with hints of irregularity. UHC: (5)
Noticable increase in contrast, with more outer nebulosity visible and
some irregular light and dark structure being visible. Nebula was visible
when UHC was held up to unaided eye!
OIII: (5) Higher contrast than
with UHC, with more dark irregular detail throughout the region, but not
quite as much nebulosity visible as in UHC. H-BETA: (1) Very faint glow
around the star cluster, not much better than without a filter (but much
dimmer).
RECOMMENDATION FOR ROSETTE NEBULA: OIII/UHC (near tie).
NGC 2264, "CONE NEBULA" near S Monocerotis.
DEEP-SKY: (2) slight
increase in contrast, with dim diffuse haze now visible and brightest spot
WSW of S Mon.
UHC: (4) Faint nebulosity now visible over entire field,
nearly a degree wide.
Dark southern inclusion "Cone" faintly visible in
southern part of nebula. OIII: (3) Dimmer than in UHC, with only the area
southwest of S Mon being easy to see (Cone not visible).
H-BETA: (1)
Only a hint of a glow southwest of S Mon.
RECOMMENDATION FOR CONE
NEBULA: UHC.
NGC 2346 (Planetary nebula in Monoceros):
DEEP-SKY (2): slightly
easier to see than without a filter.
UHC: (3) some increase in
contrast, with hints of annularity.
OIII: (3) some increase in
contrast, slightly fainter than in UHC.
H-BETA: (0) nearly
extinguished.
RECOMMENDATION FOR NGC 2346: UHC/OIII (near tie) (H-beta
not recommended).
NGC 2438 (planetary nebula in Puppis).
DEEP-SKY (2) noticably
easier to see than without a filter. Hints of annularity.
UHC: (3)
notable increase in contrast, easier to see than in Deep-sky with annular
form more noticable.
OIII: (4) much higher in contrast with annular
form now fairly obvious.
H-BETA: (0) nearly kills it
completely.
RECOMMENDATION FOR NGC 2438: OIII (H-Beta not
recommended).
NGC 2467 THOR'S HELMET (diffuse nebula in Puppis). DEEP-SKY: (2) Sparse
star cluster with a single star and a faint ball of haze around it which
is brighter on the south side.
UHC: (4) Much more contrast and detail
than in Deep-Sky with brighter linear band or arc on south side.
OIII:
(5) More contrast and detail than in UHC with the arc connected to a
"loop" which runs through the central star. Faint hints of outer detail.
H-BETA: (1) Really dims it.
RECOMMENDATION FOR NGC 2467: OIII/UHC
(H-Beta not recommended).
NGC 2359 (diffuse nebula in Canis Major).
DEEP-SKY: (2) Better
defined than without a filter but still low in contrast. UHC: (4) Higher
contrast than in Deep-sky, with arc like detail off of a central oval
mass.
OIII: (5) even more contrast than in UHC with oval mass now
looking like a loop with tendrils off each end.
H-BETA: (0) Kills most
of the nebulosity.
RECOMMENDATION FOR NGC 2359: OIII/UHC (H-Beta not
recommended).
NGC 2371-2 (planetary nebula in Gemini).
DEEP-SKY: (2) Two adjacent
faint spots, helped somewhat over non-filter use.
UHC: (4) enhanced
over Deep-Sky, with the two lobes showing hints of contact.
OIII: (4)
Slightly higher contrast than UHC. Hints of faint outer wings.
H-BETA:
(0) Kills the nebulosity.
RECOMMENDATION FOR NGC 2371-2: OIII/UHC (near
tie) (H-Beta not recommended)
NGC 2392 "ESKIMO NEBULA" (planetary nebula in Gemini) DEEP-SKY: (2)
enhanced slightly over non-filter use (easier to see the outer of the two
shells).
UHC: (4) Darkens the sky background and enhances the nebula,
making both shells quite easy to see.
OIII: (4) Jet-black sky
background with higher contrast than UHC, but the two shells almost seem
to merge (tones down the central star).
H-BETA: (0) Only the inner
shell is visible, much fainter than in UHC, OIII, or
Deep-Sky.
RECOMMENDATION FOR NGC 2392: OIII/UHC. (H-Beta not
recommended).
NGC 3242 "GHOST OF JUPITER" (planetary in Hydra).
DEEP-SKY: (2)
slightly enhanced over non-filter use (easy without filters). UHC: (4):
much higher contrast with faint circular outer halo-like shell beyond the
two inner shells now visible.
OIII: (4): much darker background but the
two inner shells really blaze out.
H-BETA: (1): much fainter (only the
innermost shell is easily seen).
RECOMMENDATION FOR NGC 3242: UHC/OIII
(near tie) (H-Beta not recommended).
NGC 4361 (planetary nebula in Corvus):
DEEP-SKY: (2) somewhat
higher contrast than without a filter.
UHC: (4) Large increase in
contrast with faint diffuse outer extensions seen. OIII: (4) Higher
contrast, a bit sharper than in UHC but nebula appears slightly
smaller.
H-BETA: (0): nearly killed by the filter.
RECOMMENDATION
FOR NGC 4361: UHC/OIII (near tie), (H-Beta not recommended).
NGC 6210 (planetary nebula in Hercules).
DEEP-SKY: (2) stands out a
bit better, but filters are not needed. UHC: (4) increase in contrast with
faint hints of close outer shell north and south of main disk.
OIII:
(4) darkens the background and also shows hints of the outer
shell.
H-BETA: (1) dims the nebula, showing only the brighter inner
core.
RECOMMENDATION FOR NGC 6210: OIII/UHC (H-Beta not
recommended).
NGC 6302 "BUG NEBULA" (planetary nebula in Scorpius).
DEEP-SKY: (2)
somewhat more contrast than without a filter. UHC: (3) noticable
improvement in contrast with central core region now seeming much brighter
and outer E-W flarings much easier to see. OIII: (3) makes the core region
really stand out, although the nebula is not quite as bright as in the
UHC.
H-BETA: (0).
RECOMMENDATION FOR NGC 6302: OIII/UHC (H-Beta not
recommended).
NGC 6334 (diffuse nebula in Scorpius).
DEEP-SKY: (2) nebula is a
large very faint glow which is brightest around one star near the south
end.
UHC: (4) two separated patches around two stars near the south
end, plus fainter patches and dark spots visible in a dim diffuse haze to
the north. OIII: (3) fainter than in UHC, but still visible.
H-BETA:
(3) similar to OIII view but slightly fainter.
RECOMMENDATION FOR NGC
6334: UHC (OIII and H-beta also useful).
NGC 6445 (Planetary Nebula in Sagittarius).
DEEP-SKY: (2) makes it
stand out better.
UHC: (4) noticably improves the contrast over
Deep-Sky.
OIII: (3) darker more contrasting field, but slightly fainter
than UHC.
H-BETA: (0) kills the nebula almost
completely.
RECOMMENDATION FOR NGC 6445: UHC/OIII (H-beta not
recommended).
NGC 6357 (diffuse nebula in Scorpius).
DEEP-SKY:
(2) not easy to see without a filter, as Deep-Sky just barely brings it
out.
UHC: (3) Noticable boost in contrast, showing some irregularity
and a brighter portion around a tiny group of stars.
OIII: (4) More
contrast than UHC, with the patch around the tiny star group greatly
enhanced.
H-BETA: (1) almost kills the nebulosity.
RECOMMENDATION
FOR NGC 6537: OIII/UHC (H-Beta not recommended).
NGC 6543 "CAT'S EYE" (planetary nebula in Draco).
DEEP-SKY: (2)
makes it stand out better.
UHC: (4) noticable contrast improvement with
faint diffuse outer halo visible.
Faint patch west of main nebula
barely visible (IC 4677).
OIII: (4) really darkens the background and
boosts the visibililty of the outer halo. IC 4677 now slightly easier to
see.
H-BETA: (1) really dims it but is still visible.
RECOMMENDATION
FOR NGC 6543: OIII/UHC (H-Beta not recommended).
NGC 6559/IC 4685 (diffuse nebula in Sagittarius).
DEEP-SKY: (2) not
visible without filters, glow around one star with hints of extensions
north and northwest.
UHC: (4), noticably enhanced with some light and
dark structure.
OIII: (2) still visible but much fainter than in
UHC.
H-BETA: (2) visible with slight structure.
RECOMMENDATION FOR
NGC 6559: UHC
NGC 6781 (planetary in Aquila).
DEEP-SKY: (3) easy without a filter
but shows more contrast with hints of annularity even at low
power.
UHC: (4) noticable boost in contrast with strong annular form
and glowing interior (notable brightening along south side).
OIII: (4)
really darkens field and enhances the annularity.
H-BETA: (0) kills the
nebula completely.
RECOMMENDATION FOR NGC 6781: OIII/UHC (H-beta not
recommended).
NGC 6804 (Planetary nebula in Aquila).
DEEP-SKY: (2) slightly easier
to see than without a filter.
UHC: (3) brings the nebula out
well.
OIII: (4) nice high contrast a bit better than UHC.
H-BETA:
(0), nearly wipes it out.
RECOMMENDATION FOR NGC 6804: OIII/UHC (H-beta
not recommended).
CRESCENT NEBULA (NGC 6888) (diffuse nebula in Cygnus). DEEP-SKY: (2)
slight improvement over no filter, with the brightest segment of the
crescent going through a star along the northern end of the nebula fairly
easy to see.
UHC: (4) Nebula is now much easier to see, appearing as a
large nearly complete oval ring of dim nebulosity with brightness
variations and a dimly glowing interior.
OIII: (5) Complete oval ring
with glowing interior and slightly higher contrast than with UHC, but
overall nebulosity is fainter than with UHC. H-BETA: (1) Very dim, with
only the brightest arc portion which was seen in the Deep-Sky filter
visible at all in a very dark field. Nebula almost gone. RECOMMENDATION
FOR NGC 6888: OIII/UHC (near tie). H-beta not recommended!)
VEIL NEBULA NGC 6960-95 (SNR in Cygnus).
DEEP-SKY: (3) Nebula is
easier to see than without a filter, with both sides ofthe loop being
visible, including the section through 52 Cygni. UHC: (4) Large increase
in detail and contrast! Nebula really stands out with some filamentary
detail. Hints of other strands in the interior of the loop. OIII: (5)
ENORMOUS INCREASE IN CONTRAST AND DETAIL with wonderful fine filaments and
strands visible even between the two main arcs, making the entire complex
closely resemble its photograph. OIII is the filter of choice
here.
H-BETA: (1) Very dim, but still visible (forget
it!).
RECOMMENDATIONS FOR VEIL: OIII (UHC is helpful, but not quite as
much as the OIII: H-BETA is NOT recommended).
NORTH AMERICAN NEBULA NGC 7000 (diffuse nebula in Cygnus). DEEP-SKY:
(2) Nebular overall form is easier to see than without a filter, but only
slightly.
UHC: (5) Very noticable improvement in contrast over the
DEEP-SKY filter, with both "Florida" and "Mexico" now quite easy to
see.
OIII: (4) Some improvement in contrast and detail, with brighter
"spine" on east side of "Mexico" and some faint dark detail being easy to
see, but nebula is somewhat fainter than in UHC.
H-BETA: (3) Detail is
similar to OIII, but nebulosity is fainter than OIII. RECOMMENDATIONS FOR
NGC 7000: UHC/OIII but both H-BETA/Deep-Sky are useful on the object (UHC
was brighter, but OIII shows more contrast).
NGC 7009 SATURN NEBULA (planetary nebula in Aquarius). DEEP-SKY: (2)
does show the anses on each end of the planetary a bit better, in the form
of two small puffs.
UHC: (4) Anses become more spike-like, with
noticable increase in contrast. OIII: (4) Nebula is dimmer, but contrast
is a bit higher, especially in the interior, where inner shell detail can
be seen.
H-BETA: (1) Nebula is noticably dimmer, appearing as just a
disk. RECOMMENDATION FOR NGC 7009: Filters are not needed, but OIII/UHC
will help bring out the fainter detail (H-BETA not recommended).
NGC 7023 Emission/reflection Nebula in Cepheus.
DEEP-SKY: (3)
Noticable boost in contrast with nebular glow expanded over no filter.
Darker areas noted on east and west sides.
UHC: (2) dimmer than in
Deep-sky and slightly smaller, but nebula still shows up better than
without a filter.
OIII: (2) dimmer than in UHC but still shows some
hints of detail. H-Beta: (1) dimmer than UHC and OIII. Only central area
around the star remains visible.
RECOMMENDATION FOR NGC 7023:
DEEP-SKY.
NGC 7027 (Planetary nebula in Cygnus).
DEEP-SKY: (2) easy without
filter, but Deep-Sky makes it stand out a little better as a small
bluish-green oval.
UHC: (4) really makes the nebula almost blaze out
and hints at large faint irregular outer shell. High power reveals
off-center central star and an interior arc southeast of the central
star.
OIII: (4) Core slightly dimmer than in UHC, but outer shell is
easier to see with hints of detail in the outer shell.
H-BETA: (0)
Really dims the nebula!
RECOMMENDATION FOR NGC 7027: OIII/UHC near tie
(H-BETA not recommended!).
NGC 7129-33 (Diffuse Nebula in Cepheus)
DEEP-SKY: (2) slight
increase in contrast, with a faint haze visible around a central group of
4 to 6 stars.
UHC: (3) Haze now easier to see with more contrast, but
still rather diffuse with some faint detail which is brightest in the
northern portion. Two other faint patches visible slightly away from the
north one.
OIII: (3) Brings out a little more detail (dark inclusion in
one side?).
H-BETA: (1) dims the nebula significantly, although it is
still there.
RECOMMENDATIONS FOR NGC 7129-33: UHC/OIII
NGC 7293 GIANT HELICAL NEBULA (planetary nebula in Aquarius). DEEP-SKY:
(2) large dim roughly circular fuzzy patch with slightly darker middle,
easier to see than without a filter, but does not have a lot of
contrast.
UHC: (4) Noticable increase in contrast, showing a clear fat
slightly diffuse ring with a glowing center and hints of structure. Nebula
is now quite easy. OIII: (5) Much more contrast than the UHC, with hints
of helical nature and indications of outer filamentary nebulosity. Dimmer
than in UHC, but stands out better than in the UHC. Best performance of
all the filters. H-BETA: (0) Barely visible in this filter (almost kills
the nebulosity).
RECOMMENDATION FOR NGC 7293: OIII/UHC (H-beta NOT
recommended).
NGC 7538 (Diffuse nebula in Cepheus):
DEEP-SKY: (3) boosts the
contrast making it easier to see than without a filter.
UHC: (4)
darkens the background and brings out the nebulosity more than
Deep-Sky.
OIII: (4) dimmer, but contrast is a bit higher.
H-BETA:
(0) Dims it nearly to extinction.
RECOMMENDATION FOR NGC 7538: UHC/OIII
(H-beta NOT recommended).
NGC 7635 BUBBLE NEBULA (diffuse nebula in Cassiopeia).
DEEP-SKY:
(2) Vague diffuse oval fuzzy area around a bright star. UHC. (3) Oval area
of nebulosity noted around the star running roughly east-west with large
very dim diffuse extensions noted to the northwest and southeast. A dim
"Y"-shaped patch can also be seen just north of the central star. OIII:
(4) Higher contrast, with the "Y"-shaped patch now much more
definite.
H-BETA: (1) Very dim, not as good as OIII, but nebula is
still visible.
RECOMMENDATION FOR NGC 7635: OIII/UHC.
NGC 7662 BLUE SNOWBALL (planetary nebula in Andromeda).
DEEP-SKY:
(2). Deep-sky filter does darken the background somewhat.
UHC: (3)
Really darkens the background, but adds only a little nebulosity. OIII:
(3) Dims the nebula slightly, giving a jet black sky background and a bit
more interior contrast (but not much more detail).
H-BETA: (1)
Significantly dims the nebula over the OIII. RECOMMENDATIONS FOR NGC 7662:
Filters are not really needed, but UHC/OIII may help with locating it at
low power via "blinking" (H-BETA is not recommended).
NGC 7822 (faint diffuse nebula in Cepheus).
DEEP-SKY: (2) Very faint
large elongated (east-west) glow around a few stars.
UHC: (3) Glow is
noticably enhanced over Deep-sky, shows some irregularity.
OIII: (2)
Fainter than UHC, but still visible.
H-BETA: (2) fainter than the UHC,
but shows about as much detail as UHC.
RECOMMENDATION FOR NGC 7822: UHC
(H-Beta and OIII also useful).
IC 405 FLAMING STAR NEBULA (diffuse emission/reflection nebula in
Auriga). DEEP-SKY: (3) Nebula visible as a very faint diffuse glow with
irregularities around and to the east of AE Aur. Not clearly visible
without filters. UHC: (2) Slight increase in contrast showing faint
arc-like filament north-east of AE. Faint background glow fainter than in
Deep-Sky filter. OIII: (1) Only hints of nebulosity.
H-BETA: (2) Hints
of arc and one other faint patch north of AE but nebula is fainter than in
UHC or Deep-Sky.
RECOMMENDATION FOR IC 405: DEEP-SKY/UHC (no filter
helps a lot, and may be mostly a reflection nebula).
IC 410 (Nebula assoc. with NGC 1893 in Auriga)
DEEP-SKY: (2) faint
glow running E-W through the "Y"-shaped cluster NGC 1893 with southward
extension off east end.
UHC: (4) detailed arc-like irregular
nebulosity running east-west and then curving south with darker inclusion
along southwest side.
OIII: (4) Brings out more dark detail along the
east and south sides, but nebula is dimmer. Really stands out, as nebula
follows the form of the cluster.
H-BETA: (0) Nebula is almost wiped
out.
RECOMMENDATION FOR IC 410: OIII/UHC. (H-beta not recommended).
IC 434 HORSEHEAD NEBULA (diffuse nebula in Orion).
DEEP-SKY: (2)
Little change is seen from viewing without a filter. When visible, it
appears as a weak dark gap in the dim north-south nebulosity, and the
shape is hard to see. Nebula is difficult, unless viewed under very dark
and clear conditions.
UHC: (3) Horsehead now stands out weakly, showing
some of the horsehead shape with averted vision, a definite improvement
over no filter or the DEEP-SKY. OIII: (0) No Horsehead seen. IC-434
nebulosity only hinted at. H-BETA: (4) Nebula still dim, but Horsehead
shape now fairly easy to see, showing up with more contrast than with the
UHC filter. East edge of IC 434 seems brighter than the rest of the nebula
with the H-beta.
RECOMMENDATION FOR HORSEHEAD: Lumicon H-BETA (UHC also
helps, but OIII not recommended).
IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus). DEEP-SKY: (2)
Brings out a large faint diffuse nebulosity in two elongated segments with
a darker area between them east of Gamma Cygni. Larger area well northwest
of Gamma also visible.
UHC: (3) Increase in contrast noted over
Deep-sky filter, with dark gap between the patches east of Gamma Cygni now
much more notable. OIII: (1) Filter almost extinguishes the nebulae (very
faint). H-BETA: (3) Nebula is fainter than in UHC, but has higher contrast
with a very dark sky background in the areas around the
nebulosity.
RECOMMENDATION FOR IC 1318. H-BETA/UHC (near tie) (OIII not
recommended)
IC 1396 (nebula S.W. of Mu Cephei).
DEEP-SKY: (2) Diffuse haze
around a weak open star cluster, quite large with some vague brightness
irregularities and a possible dark inclusion in the south side
(B161).
UHC: (3) Nebulosity more visible and dark inclusion is much
more definite, but the glow is still faint. Some variations in brightness
are noted, but the object is still rather diffuse.
OIII: (0) Kills the
nebulosity.
H-BETA: (1) Nebulosity is visible, but is extremely dim in
a dark background.
RECOMMENDATION FOR IC 1396: UHC/DEEP-SKY. (OIII not
recommended).
IC 1848: (Diffuse Nebula, Cassiopeia).
DEEP-SKY: (2) some increase
in contrast with nebula appearing as an elongated faint haze going through
a sparse cluster.
UHC: (4) Much easier to see, with nebula now
elongated E-W, brighter on northern side.
OIII: (4) noticably darker
than UHC, but a little higher contrast.
H-BETA: (1) Very
dim.
RECOMMENDATION FOR IC 1848: UHC (H-beta not recommended)
IC 2177: (Diffuse Nebula, Monoceros).
DEEP-SKY: (2) long faint
irregular diffuse band of haze not easily seen without filters. Extends
southward from open cluster NGC 2235. UHC: (3) Easier to see, with
somewhat more contrast. Narrower slightly sinuous core filament imbedded
in more diffuse haze visible for nearly 2 degrees.
OIII: (2) Nebula
barely visible, with most of outlying nebulosity gone.
H-BETA: (3) Core
filament is fainter than UHC, but considerably more
contrast.
RECOMMENDATION FOR IC 2177: H-BETA/UHC.
IC 4628 (diffuse nebula in Scorpius):
DEEP-SKY: (2) faint diffuse
irregular glow not visible without filters. UHC: (4): Noticable
improvement, with nebula now easy to see and rather detailed, with some
irregular lane-like detail.
OIII: (2): much fainter than in UHC, but
still visible.
H-BETA: (3): shows some interesting filamentary detail,
but not as bright or as detailed as in UHC.
RECOMMENDATION FOR IC 4628:
UHC.
PELICAN NEBULA (IC 5067-70) (diffuse nebula in Cygnus):
DEEP-SKY:
(2) Nebular overall form is easier to see than without filters, with some
hints of detail and the overall form.
UHC: (4) Very noticable
improvement in contrast over the DEEP-SKY filter, with both the "beak" and
the "body" now fairly easy to see.
OIII: (4) Improvement in contrast
and detail, but nebula is dimmer than UHC.
H-BETA: (2) Nebulosity is
visible but is very faint.
RECOMMENDATIONS FOR IC 5067: UHC/OIII,
Deep-sky also useful on the object (UHC was brighter, but OIII shows more
detail).
IC 5146 THE COCCOON NEBULA (diffuse nebula in Cygnus). DEEP-SKY: (2) A
bit better than no filter, but object is still easily seen as a dim
roughly circular irregular patch in some stars without a filter. UHC: (3)
Slightly higher contrast with more irregular interior dark
detail.
OIII: (1) Fainter and slightly smaller than in UHC (OIII hurts
it). H-beta: (3) dimmer than UHC but shows larger area of outer nebulosity
and slightly better defined dark detail in the form of irregular lane like
features.
RECOMMENDATIONS FOR IC 5146: H-BETA/UHC near tie (OIII not
recommended).
PK205+14.1 "MEDUSA NEBULA" (large planetary nebula in
Gemini):
DEEP-SKY: (2) Slight increase in contrast but nebula is still
just a very faint diffuse hazy area.
UHC: (3) noticable increase in
contrast with vague "C" shaped arc now visible. OIII: (4) dimmer than in
UHC, but slightly more contrast, with hints of filaments in the dark part
(looks almost annular).
H-BETA: (0) Completely kills the
nebula.
RECOMMENDATION FOR PK204+14.1: OIII/UHC near tie (H-beta not
recommended).
PK164+31.1 "HEADPHONE NEBULA" (large planetary nebula in
Lynx).
DEEP-SKY: (2) Very slight increase in contrast over non-filtered
view.
UHC: (3) noticably easier to see as two spots connected by a
vague annulus.
OIII: (3) much easier to see the spots, but the annulus
fades somewhat.
H-BETA: (0) Completely kills the
nebula.
RECOMMENDATION FOR PK164+31.1: UHC/OIII near tie (H-beta not
recommended).
Sh-2-13 (Diffuse nebula in Scorpius).
DEEP-SKY: (2) dimly visible as
a very faint glow but not without the filter.
UHC: (4) boost in
contrast, becoming very patchy but still dim.
OIII: (2) fainter but
still visible.
H-BETA: (2) similar to OIII.
RECOMMENDATION FOR
SH-2-13: UHC
Sh-2-54 (Diffuse nebula in Serpens).
DEEP-SKY: (2) dim diffuse glow
not visible without filters.
UHC: (4) noticable contrast gain, with
considerable light and dark detail.
OIII: (2) much fainter than in UHC
but still visible.
H-BETA: (3) better than in OIII with a little
detail.
RECOMMENDATION FOR Sh-2-54: UHC
Sh-2-84 (Diffuse nebula in Sagitta).
DEEP-SKY: (1): only hint of
nebula.
UHC: (3): faint diffuse "L"-shaped patch with irregular
edges.
OIII: (1): dark field with just a hint of nebulosity.
H-BETA:
(2): fainter than in UHC.
RECOMMENDATION FOR Sh-2-85:
UHC.
Sh-2-101 (Diffuse Nebula in Cygnus): Only hinted at without
filters. DEEP-SKY: (2) Very faint moderate-sized diffuse haze in two
segments around 3 stars (2 stars on the west and one on the east).
UHC:
(3) Higher contrast but still faint. Two definite patches visible with
hazy arc-like extensions. One on the west apppears larger. OIII: (2) Very
dim but still visible.
H-BETA: (3) Almost as much nebulosity visible as
in UHC, but dimmer.
RECOMMENDATION FOR Sh-2-101: UHC/H-BETA.
Sh-2-112 (Diffuse Nebula in Cygnus N.W. of Deneb): hinted at without
filters. DEEP-SKY: (3) faint star with very faint small diffuse patch of
nebulosity to its immediate south. Much easier to see than without a
filter. UHC: (4) Almost fan-like diffuse patch extending from the faint
star to its south. More nebulosity visible than in Deep-Sky, but still
somewhat small. OIII: (4) Fainter than UHC, but the nebula now envelopes
the star in a diffuse faint haze. Darker inclusion from the northeast now
visible. H-beta: (1) Really dims it!
RECOMMENDATION FOR Sh-2-112:
OIII/UHC (H-beta not recommended).
Sh-2-132 (Diffuse Nebula in Cepheus)
DEEP-SKY: (2) better than
without filters as without filters the object is only hinted at. Just a
very faint diffuse irregular glow around several stars roughly elongated
east-west.
UHC: (3) Makes a patch on south edge easier to see and hints
of other detail. OIII: (4) Increases contrast with an arc across the
northern side and a patch in the middle. Higher contrast but dimmer than
UHC.
H-BETA: (2) Dims it more than OIII, but nebula remains
visible.
RECOMMENDATIONS FOR Sh-2-132: OIII/UHC.
Sh-2-155 (Diffuse nebula in Cepheus).
DEEP-SKY: (2) very faint
diffuse area of haze around two widely-spaced stars (better contrast than
without a filter).
UHC: (1) Only hint of nebulosity visible.
OIII:
(1) little if any nebulosity visible.
H-BETA: (0) no nebulosity
visible.
RECOMMENDATION FOR Sh-2-155: DEEP-SKY (probable reflection
nebula).
Sh-2-157 ("fingers" diffuse nebula in Cassiopeia).
DEEP-SKY: (2)
not easily seen except as a vague elongated brightening in a rich star
background.
UHC: (3) Elongated large diffuse and dim oval feature with
two dim northward-pointing arcs.
OIII: (3) Nebula is fainter than in
UHC, but still visible with increased contrast, especially in the two
"finger" patches.
H-BETA: (2) Fainter than in OIII, but nebula is still
visible.
RECOMMENDATION FOR Sh-2-157: UHC/OIII
Sh-2-170 (faint diffuse nebula in Cepheus).
DEEP-SKY: (2) not easy
to see without filters. Round very faint very diffuse patch of haze around
a group of 6 or 7 faint stars.
UHC: (3) Somewhat easier to see than in
Deep-Sky, with a bit more contrast.
OIII: (2) Still visible, but
fainter than in UHC.
H-BETA: (2) Still visible but fainter than in OIII
or UHC.
RECOMMENDATION FOR Sh-2-170: UHC
Sh-2-171 (very faint large diffuse nebula in Cepheus).
DEEP-SKY: (2)
Plainly visible over non-filter, but still faint and diffuse.
UHC: (3)
Slight enhancement over Deep-Sky with some light and dark areas. OIII: (2)
Fainter but shows more enhancement in several dark lane-like
structures.
H-BETA: (2) Nebula remains visible, but just a bit fainter
than in the OIII.
RECOMMENDATION FOR Sh-2-171: UHC (Deep-Sky and OIII
filters also useful).
Sh-2-261 (diffuse nebula in Orion):
DEEP-SKY: (2) slight increase
in contrast making the nebula faintly visible and easier than without a
filter.
UHC: (3) nebula now clearly visible but still faint.
OIII:
(3) nebula visible, but fainter than UHC with a bit more
contrast.
H-BETA: (2), nebula is still visible, but not quite as good
as in UHC/OIII.
RECOMMENDATION FOR Sh-2-261: UHC/OIII (near tie).
Sh-2-276 "BARNARD'S LOOP" (diffuse nebula in Orion).
**(Naked-eye
observations with filter over unaided eye).
DEEP-SKY: (1) hint of a
glow in telescope, but not visible naked eye. UHC: (2) Faint arc like glow
visible under good conditions over Orion's Belt, continuing southward east
of the belt.
OIII: (0) No nebulosity seen.
H-BETA: (3) Faint glow
visible both over the belt and curving down southeast along Orion's
southeastern side. Very faint, but noticably easier to see than in UHC
filter.
RECOMMENDATION FOR Sh-2-276: H-BETA/UHC. (OIII not
recommended)>
Sh-2-235 (diffuse nebula in Auriga).
DEEP-SKY: (3) diffuse oval
faint fuzzy patch, slight southern extension.
UHC: (3): slightly more
contrast than Deep-Sky, but fainter.
OIII: (2): fainter than UHC or
Deep-Sky.
H-BETA: (4): Faint, but two patches are now seen with
brighter one on the north. More contrast than Deep-Sky or
UHC.
RECOMMENDATION FOR Sh-2-235: H-BETA/DEEP-SKY (UHC also
helps.).
vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177). DEEP-SKY: (2)
Slight boost in contrast, showing more nebulosity than without a
filter.
UHC: (3) More contrast and nebulosity visible, but still faint.
OIII: (1) Fainter than in UHC, with only hint of a glow around the central
star.
H-BETA: (4) Better defined than any of the other filters, with
more light and dark detail. Fainter than in UHC, but shows better contrast
and detail. RECOMMENDATION FOR vdB93: H-BETA/UHC (OIII not
recommended).
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