Filter Performance Comparision for some common Nebulae PART 2

[AshObservatory]

by David Knisely, Prairie Astronomy Club **** Reproduced with permission from author ****

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 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 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: UHC/OIII (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, but somewhat higher contrast. The "Cone" wasbarely glimsed but only the area southwest of S Mon was all that bright.

H-BETA: (1) Only a hint of a glow southwest of S Mon.

RECOMMENDATION FOR CONE NEBULA: UHC.

NGC 2359 THOR'S HELMET (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 ring-like mass.

OIII: (5) even more contrast than in UHC with oval mass now looking like aloop with tendrils off each end.

H-BETA: (0) Kills most of the nebulosity.

RECOMMENDATION FOR NGC 2359: OIII/UHC (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 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 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).

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 of the 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 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 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).

[Astrodread]

Just what i was looking for. Ive just got a Oiii and UHC filters and i cant wait to see how they perform. Thanks so much