Some "obscure" planetary nebulae

[Steve Gottlieb]

Scott Harrington wrote an article in the October issue of Sky & Tel on 10 obscure planetary nebula and I thought I’d post my own observations with a variety of larger scopes.  Most of the ones he discusses are small and fairly recent discoveries.  Several are located in rich Milky Way fields, so you really need a good photographic finder chart (or deep stellar magnitude chart) to pinpoint the location. A couple of the observations were made last night in pretty good conditions, when I wasn’t following the Titan transit!

Steve

 1)  PHR J1851-0732

18" f/4.3 at 175x (8/1/08): Since this planetary is a recent MASH discovery (2006), I was pleasantly surprised to find a relatively bright, fairly small disc at 175x using a NPB filter just west of a mag 12 star (barely detached).  A fainter star is just off the NW edge.  The planetary had a slightly elongated halo, ~30"-35" in diameter, with a fairly crisp edge.  Removing the filter, it was very difficult to identify the planetary as it resides in a rich field 75' S of M11 and the suspected haziness at the position was similar to the general Milky Way patchiness in the field.

 

2)  SB 20 = PHR J1849-1952

18" f/4.3 at 300x (9/15/07): Picked up at 300x as a very small, faint glow ~5" diameter attached on the NW side of a mag 14.5 star with a fainter mag 15.5 star sometimes visible on the NW edge of the glow.  Adding a DGM Optics NPB filter, the contrast increased significantly and the planetary was visible continuously with averted vision as a ~10" disc.  Surrounded by a small, partial 2' ring of mag 13-15 stars.  This planetary was discovered in a recent H-alpha survey (1999ApJ...515..610B) and independently in the new MASH catalogue.

 

3)  Kronberger 56

18" f/4.3 at 275x (7/25/09): On the suggestion of Dana Patchick (observing together) we took a look at this new planetary candidate.  This object was discovered by Matthias Kronberger in a visual search using the DSS on May 13, 2009 and he first observed it in a 15" f/4.2 Obsession on July 21, 2009, from Austria .  Our observation was just 4 days later.

 

In my scope at 275x (unfiltered) it appeared as a small, hazy spot with a mag 14.5-15 star at or just off the SE end.  The main glow was ~15" in diameter and had a very low surface brightness.  The shape seemed slightly irregular or elongated, though it was too faint to pin down a distinct outline.  Occasionally an extremely faint superimposed star was seen.  This new planetary is located 6.3' NNW of mag 6.9 HD 185044 and forms a small triangle with two 14.5-magnitude stars 1.6' WNW and 2' N.  A faint, very close double star just 1.5' SW was initially mistaken as the planetary when we first identified the field.

 

We also spent close to an hour observing the object in Greg's 22" at various magnifications using a UHC and OIII filters.  At 462x, the star off the SE end was cleanly resolved and the planetary displayed a moderate contrast gain using a UHC filter (easy to hold continuously).  I felt the UHC filter gave a better contrast boost over the OIII, though perhaps at a lower magnification the OIII would have been more helpful.  The overall size seemed roughly 20"x15".

 

4)  LSA 1

17.5" f/4.5 at 220x and 280x (8/15/01)

Faintly visible without filter at 220x and verified with a UHC filter as a small, round disc.  Excellent view at 280x and UHC; steadily visible as a crisp-edged, evenly lit 10" disc.

 

24" f/3.7 at 229x (8/18/25): visible unfiltered as a soft, round, ~15" disc.  Nice contrast boost with a NPB filter, edge sharpens up, stands out well continuously.  Located 3' NNE of a 10th mag star.

 

5)  Necklace Planetary (IPHASX J194359.5+170901)

48” f/4.0 at 488x (10/22/11): Not knowing what to expect, we were surprised that the Necklace Planetary was easily picked up with direct vision as a faint, fairly small, oval glow with an irregular surface brightness.  The oval was slightly elongated WNW-ESE, ~20"x15".  A mag 14.5 star is close off the SE end.  The nebula was mottled in spots and brighter along the north to west portion of the rim.  With careful viewing the NW end of the planetary resolved into a couple of faint, extremely small knots with one directly at the NW end that was easily seen.

 

24" f/3.7 at 229x and 327x: very faint, small, round glow unfiltered.  Adding a NPB filter at 229x, easily visible as a small, crisp disc. No other details noted.

 

6)  ETHOS 1

48" f/4.0 at 375x and 488x (10/23/11): A very small, round glow, ~15" diameter, was easily seen surrounding a faint central star.  Very faint wings or jets extended SW and NE.  At 488x the jets were easily visible with a Sloan G filter.  With this combination, the planetary resembled an edge-on galaxy, ~40" in length, with a brighter core.  A faint star (actually a double) is near the SE tip, while the NW extension has a faint star (also double) just east of the tip. The jets were visible without a filter, though not as well defined.

 

24" f/3.7 at 225x and 285x (10/13/12): the central 12" region was glimpsed unfiltered at 225x but was better seen at 285x as a faint, very small glow, visible ~⅓ of the time.  Helping to pinpoint the location is a 48" string of three mag 13.3/13.7/14.3 stars about 1.5' N of Ethos 1 and a mag 15 star just 35" NE.  I tried using a NPB filter, but the contrast was only improved marginally at 225x, if at all.  The extensions or "wings" were not seen.

 

7)  Patchick 1

18" f/4.3 at 160x (10/25/03): This planetary nebula candidate was just discovered by Dana Patchick on a blue DSS plate and it appears to be a compact HII region or a new PN discovery!  Not visible without a filter at 160x.  Using an OIII filter, an extremely faint, small disc was visible, ~10" diameter.  Once the precise location was pinpointed I could hold the nebula most of the time.  Located in a rich Cygnus star field.

 

8)  Kronberger 23

24" f/3.7 at 176x: Visible as a faint, round disc, perhaps 10" in diameter.  Located in a rich star field (star hopped from HJ 1532, a 12" pair of mag 10.3/12.5 stars).  A mag 9.6 star is 4' WSW.

 

9)  Kun 4 = ETHOS 4

24” f/3.7 at 229x, 375x and 500x (8/18/25): Easily visible "star" at 229x. Roughly the same brightness as a mag 14.5 star 1.4' SE and much fainter than a 12th mag star 3.5' SE (the two stars and PN are collinear).  Adding a NPB filter, the PN is much more prominent than the nearby star and comparable to the 12th mag star.  So, there is a 2+ magnitude gain in contrast.  Increasing to 375x, it seemed "soft" compared to the sharp nearby stars and there was a definite small disc 2"-3" at 500x.

 

10)  Howell-Crisp 1

18" f/4.3 at 115x (11/18/06): This object was just rediscovered on images taken by Michael Howell and Richard Crisp and assumed to be a possible planetary.  While observing with Ray Cash and Mark Wagner, Ray took a stab at this object with his 13.1-inch using a UHC filter and it was marginal at best in partially cloudy conditions.  I later took a look in my scope when the sky was clear and it was definitely visible, though still only glimpsed part of the time with averted vision at 115x using a DGM Optics NPB filter.  It appeared as an extremely low surface brightness hazy spot, perhaps 30" in diameter.  Mark felt the object had an irregularly round shape with an occasional sharp edge on its SW perimeter.  A trio of faint stars 1' W pinpointed the position.  Located 37' ENE of the reflection nebula IC 444.

 

24" f/3.7 at 200x (1/31/14): Picked up unfiltered as 200x knowing the exact location.  Adding a DGM Optics NPB filter, this PN was visible continuously with averted vision and appeared very faint, roundish, 30" diameter, low fairly even surface brightness.  A mag 15 star is at the northeast edge.  Located 10.7' SSW of mag 7.3 HD 44251.  Three mag 10 stars lie 4.6' W, 7' SW and 8' WNW.