| 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).
|
