At 100x, NGC 40 appears (unfiltered) as a slightly elongated, moderately
bright disc surrounding a bright mag 11.5 central star. A slightly fainter
mag 12 star lies 1.0' SW. I targeted this object because it is an unusually
low excitation PN, with an OIII/H-beta ratio of 0.4. In most PNe, this ratio
is runs from 10:1 to 20:1. This implies that on NGC 40, the OIII filter is
not the best choice and as predicted there was a noticeable enhancement using
the H-beta filter and it dimmed with a 2-inch OIII. At 220x, a star was
intermittently visible at the SW edge and the PN was slightly elongated
SSW-NNE. The best filter response using this power was with the UHC. The
surface brightness appeared irregular -- darker around the central star and
slightly brighter along the west and east side of the rim. At 280x, the faint
star I had earlier noted was barely off the SW edge and PN was weakly annular
with a brighter rim along the west and east side and a darker center. The SW
and NE ends of the halo were clearly weaker, though. 380x provided a nice
view with subtle irregularities in the interior.
NGC 246 in Cetus 00h47.1m -11d52'
At 100x, NGC 246 appears as a moderately bright, 3.5' irregular glow with a
darker center and encompassing four stars including a 12th magnitude central
star. Excellent contrast gain using an OIII filter, which sharpens up the
edge of the roundish annulus and enhances the irregular surface brightness.
The halo is brightest along the 270° arc running from SW to NE and is clearly
weakest on the E edge of the halo. A mag 11.5 star is embedded at the NW
edge of the halo 2.0' from center. The irregular central hole is much darker
but faintly luminous. Also superimposed is a mag 12 star SW of the central
star and a 4th star is just inside the eastern boundary. At 220x, the
western 90° outer arc is brightest and there appears to be a knot embedded at
the NE edge of the halo.
Abell 4 in Perseus 02 45 +42.6
At 105x and OIII filter appears faint, small, round. Can hold steadily with averted vision, estimate V = 14.5-14.7.
Nice view at 220x and UHC filter although visible without filter at this power. Smaller than most Abell planetaries.
Located 40' ESE of M34.
Sharpless 2-188 in Cassiopeia 01 31 +58 24
This huge filamentary complex was discovered at the Simiez
observatory in Russia in 1951 and was relisted in a survey by Sharpless in
1959. Jay McNeil provided me with background information on this interesting
object. Both Simiez and Sharpless classified this object as an emission
object and at one point it was considered both an HII region and a SNR based
on its wispy appearance (like a dim version of Pickering's Wedge in the
Veil). It wasn't until the 90's that Simeiz 22 first appeared in PNe lists
and it is now considered an ancient, crescent-shaped planetary similar to the
Medusa Nebula (Abell 21). The best view of this phantom object was at 100x
(20 Nagler) using an OIII filter. With averted vision, a large, low surface
brightness glow was visible, elongated ~E-W and perhaps 8' in length with a
better defined southern edge. Several mag 13-14 stars are superimposed. It
wasn't easy to identify this planetary (definitely not your garden-variety
type).
NGC 1360 in Fornax 03h33.2m -25d52'
This unusually bright and large planetary is elongated 3:2 SSW-NNE, 6'x4'
diameter with a striking central star mag 10.5-11. The surface brightness is
high and fairly smooth. A truly striking object with or without filters!
NGC 1514 in Taurus 04h09.3m +30d47'
At 100x (20mm Nagler), NGC 1514 in Taurus
displays a round, 2' halo surrounding a prominent mag
9.5 star. There was an excellent response to UHC and OIII blinking
and no response to the H-beta filter (In this case, the OIII/H-beta ratio
runs at 12:1). Using the OIII filter, the surface brightness was noticeably
uneven, with the NW quadrant of the rim clearly brighter. The SE side was
also weakly enhanced while the center and ends of the minor axis were
slightly darker. At 220x using a UHC filter, the halo appears nearly 2.5' in
diameter. There was a small, darker "hole" surrounding the central star and
the halo was clearly irregular with a brighter "knot" on the SE side, while
the NW portion of the halo was brighter along the rim.
NGC 1535 in Eridanus 04h14.3m -12d44'
Back in 1980, I logged the beautiful double-shelled planetary NGC 1535 as
"greenish", but in several subsequent observations with 13" and 17.5" scopes
it has appeared blue to me. Has anyone noticed a perceived color difference
based on aperture (or possibly aging eyes?). This PN has a wonderful
double-shell structure which was easily visible at 100x surrounding the
bright central star. The view at 380x and 500x is superb in the good seeing.
The double shell envelope is very prominent with a bright inner ring ~20"
diameter with a fairly sharp edge embedded in a fainter roundish halo roughly
doubling the diameter. The inner shell is irregularly darker surrounding the
central star (I've previously described this structure as "small dark gaps"
in my observing notes).
IC 418 in Lepus 05h27.5m -12d42'
The diminutive planetary, IC 418 in Lepus, has gained some notoriety lately
because of reports of a unique pinkish hue. I've noticed this coloration
twice, but the effect is pretty subdued to my eyes. At 82x, the mag 10.5
central star was enveloped in a very small round halo which appeared to have
a slight reddish tinge at its edge. Once again, this is a low-excitation
planetary (OIII/H-beta = 1.2) and using a H-beta filter, the halo brightened
while the central star dramatically faded, leaving a more noticeable disc. At
220x, the prominent central star was surrounded by a well-defined 10" halo
which partially "blinked" on and off by switching from averted to direct
vision. At 280x, the small halo was possibly surrounded by an extremely faint
envelope, but this could not be confirmed, 380x and 500x presented a superb
view of the inner disc which appeared weakly annular.
Abell 12 in Orion 06 02 +09.7
At 220x and UHC filter; moderately bright, round, moderately large. Difficult to view as overpowered by glow of mag 4.1 Mu Orionis 1.2' WNW! Easier at 294x which cleanly separates the pair, estimate V = 12. Takes 412x which puts more room between Mu and Abell 12.
Abell 21 in Gemini 07 29 +13.3
At 100x and OIII filter the "Medusa Nebula" appears moderately bright, very large with a distinctive thick "horseshoe" shape open to the W. The S and SW portion of the rim are brighter and the rim is incomplete on the W and NW side. A brighter star is embedded in the NE portion of the rim.
NGC 2371/72 in Gemini 07h25.6m +29d29'
The appearance is very unusual at 380x with two bright knots oriented SW-NE
about 30" between centers. The SW knot is 15"-20" in size, slightly
elongated and the brighter of the two. The NE condensation has a slightly
lower surface brightness and appears ~20" in diameter. Symmetrically placed
between the knots is a faint 14th magnitude central star. Weaker nebulosity
connects the two knots giving a dogbone appearance and a faint rounder halo
encases the structure.
Jones Emberson (JE) 1 in Lynx 07h57.8m +53d25'
At 82x using an OIII filter this huge annular planetary is slightly elongated
with two brighter "knots" along the rim. These appear as large enhanced arcs
with the SE arc the most prominent. A pair of small galaxies NGC 2474 and
2475 lie 33' south.