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Messages - mccarthymark

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1
Observing Reports / OR from Pinnacles 10/14
« on: Yesterday at 11:09:58 PM »
Fearing the Bay Area would be a loss for smoke, I started driving south on 101, intending to get to Lake San Antonio or maybe Williams Hill, thinking it would be far enough south to avoid the worst of the smoke.  But as I approached Soledad, I saw thick smoke haze on the horizon which would surely impede any views--apparently from another fire in the central valley.  So I turned off and headed up Route 146 to the Pinnacles, which had some blue sky above it.

I had read that the moon was to occult Regulus in the early hours of the 15th, and that at 3:10am local time (or Burbank time, from the occultation timing list I saw online—which made me assume I would be able to see it), the star would emerge from behind the moon, briefly revealing the 12th magnitude white dwarf companion star.  This was something I wanted to see!  But where could I set up the scope with a view to the east?  The visitor center parking is fronted by a hill to the east; the Chaparral parking lot has the hoodoos in the way, and the overflow lot is ringed with trees.  I drove back to the visitor center lot and decided to wheel my 20-inch scope to the small circular amphitheatre on the east patio of the visitor center building.  It was the only view to the east to be had but was still blocked by the Pinnacles.

SJAA was running a public viewing event and I hosted the few guests who wandered over to my area, showing M11, M31, M57, and so on.  Sometimes a guest came by while I was looking at something obscure, and they gamely gave it a look.

Conditions seemed to vary a great deal through the night.  OK seeing early on, but after 1am it turned poor.  SQML was 21.3.  Light dome from Soledad washing out much of the west.  Nevertheless my notes show it was a respectable session, with these highlights:

UGC 12476: Floats to south of mag 7.8 star HD 219627; oval, gradually brighter to middle, diffuse edges, moderately large, moderately faint.  [S0a, 1.1”x0.68, 14.1b].  I showed this to a couple of guests, and they were able to see it after I sketched the field for them; not the typical public star party object!  205x

SN 2017glx in NGC 6824 Cygnus: Galaxy an oval 3:2 NE-SW elliptical glow, slightly brighter core [Sab, 12.2v].  SN briefly appears as a brightening to the core but is uncertain, and not held.    Type Ia-91T (z=0.011).  Discovery mag 14.0 on 20 Sept, but may have faded or is too close to the core to see well – seeing not supporting 333x well. Double star with yellow A, blue B is close to the north.

Hickson 16 in Cetus: Stopped to view this while star hopping to NGC 988.  A string of 4 galaxies arrayed in an arc to the south of a star.
a = NGC 835, is brightest, a moderately large round glow with brighter core region [SBab/P, 12.1v]. 
Almost connected to it and just to the west is b = NGC 833, fainter and smaller 3:2 elliptical glow E-W with relatively brighter core [Sa/P, 12.7v]. 
c = NGC 838 is to the ESE, small, faint, and round glow [S0, 13.0v]. 
d = NGC 839 completes the arc, small, very faint 4:1 glow E-W with slightly brighter core [S0/P, 13.1v]. 
NGC 848 nearby, but not part of the Hickson group.  Faint, small, 4:1 NW-SE, brighter core area and faded tips.  SBab, 13.0v

SN 2017gmr in NGC 988 in Cetus: Galaxy sprouts to the SE as a “comet tail” from 7.2 magnitude star 79 Ceti.  Long, 4:1 SE-NW, with some mottling in the halo.  This would be a spectacular galaxy if the star were not in the way [SBc, 11.0v].  The SN is a faint point on the N rim of the SE tip of the galaxy’s halo, easily held but quite faint.  Mag 14.0 at discovery 18 Sept., Type II.
 
Comet C/2017 01 ASASSN: 121x: Large half a FOV (0.4°) round diffuse coma, greenish color, what I presume to be the psudonucleus and not a centrally placed star seen momentarily with averted vision.  Comet filter enhanced coma showing more variation in coma density and brightness through the amorphous round glow.

NGC 507 Group:  In Perseus.  Area speckled with galaxies, most small and needing averted vision to brighten, but many seen direct vision and lying only 1° of each other.  Did not see all group members, and these are what I got down – there were more!
   NGC 507 = Arp 209: Bright, large, round, very bright core and diffuse halo.  E-S0, 11.2v
   NGC 508: Immediately to north of N507, appears as a second core: Small, fairly bright and round, on the outer mist of N507’s halo.  E0, 13.1v
   IC 1687: very faint and small, round, glimpsed with AV next to a star just to its west.  13.6v
   NGC 503: To the NE of N508, N503 is small, very faint, slightly elongated NE-SW, faint.  E-S0, 14.1v
   NGC 501: To N of N303, N501 is very faint, very small, round with a brighter center.  E0, 14.5v
    NGC 499: Northern part of N507 Group.  N409 is brightest in this area, elongated 3:2 W-E, with a fairly bright core and thin diffuse halo.  E-S0, 12.1v.  Forms a triangle with N496 to N (very faint, 3:1 NE-SW; Sbc, 13.4v) , N495 to W (very faint and small, 3-1 N-S; S0-a, 12.9v) , and N498 (extremely small, faint, round, needed AV; S0, 14.3v) in between N499 & N496
   NGC 483: NW from center of Group, precedes two stars: Bright, small, mostly round to slight oval, bright small core.  S, 13.2v.
   IC 1682: Very small, extremely faint, needed AV to see, elongated 3:1 NW-SE; bright star to SW.  14.0v.
   NGC 494: SW of Group center.  Pretty large glow elongated E-W, 4:1, bright core and diffuse halo.  Sab, 12.9v.
   NGC 504: rather bright but small, bright core, diffuse halo tips, elongated NE-SW 3:1.  S0, 13.0v
   IC 1690: Excessively faint, needed AV to see and could not hold DV.  Very small oval NW-SE.  13.9v

Hickson 10: Andromeda. 
a = NGC 536: Stellar nucleus, 3:1 W-E diffuse halo.  Photos show widely warped and swept out spiral arms.  SBb, 12.4v
b = NGC 529: Bright small nucleus, bright core, oval, even surface brightness.  E-S0, 12.1v.
c = NGC 531: Near star to NE; need AV to notice but can hold DV, stellar nucleus, very faint, small, elongated 3:1 NE-SW.  SB0-a, 13.8v.
d = NGC 542: Very small, extremely faint, need AV to see; slight elongation NW-SE.  Sb, 14.8v

NGC 1186: 3:1 elongated NW-SE, moderately bright and large.  Bright nucleus and core with a superimposed star on the SW rim of the core.  Averted vision brightens the core and lengthens the diffuse fading tips.  SBbc, 11.4v

NGC 1193: Pretty faint, small condensed open cluster with some dozen stars resolved over a milky glow of unresolved stars.  II3m.  Near bright star pair to the NW.  Rather pretty!  The cluster is old, 4.2 billion years.

NGC 1245: Loops of stars in random, intertwining pattern, shot through with dark lanes.  The loops are made of cords of unresolved faint stars with the bright / resolved stars over the cords, leaving dark lanes and gaps in between.  Overall box-like shape to the cluster.  No nebulosity seen.  III1r.  1b year old cluster near the Perseus arm.

HaWe 3 (= Hartl-Dengel-Weinberger 3 / HDW  3): At 87x and using OIII, I suspected an excessively faint large round grey scale change in the plotted area; no central star seen [it turns out to be 17th mag].  A tentative observation, since it was more felt momentarily with averted vision than seen.  Nevertheless it matches other reports I can find online.

NGC 1160: Not too faint, small, elongated 2:1 NE-SW, with a mottled halo hinting of spiral structure.  Seems to be an appendage on north rim of halo above the core – might be superimposed star?  [‘Tis].  Scd, 12.8

By now it was 2:40am.  Gary C. kindly came over to keep me company, and we talked while waiting for the moon to rise.  Gary checked his tablet and found out the moon was still below the horizon, and would only be 2% above the horizon when Regulus was to reappear in a half hour.  There would be no chance for me to see the star in the scope after all.  So feeling like a fool I packed up and went to a dreamless sleep in my van before packing up and leaving before dawn.

2
TAC Visual / Re: Dinosaur Point is on again for the fall and winter
« on: October 10, 2017, 01:47:04 PM »
Probably the further south one is the better.  I check this website for recent satellite imagery of fire smoke when planning an outing in fire season.  Click on the area you want to see then click on one of the image files.
https://fsapps.nwcg.gov/afm/imagery.php

3
Observing Reports / challenging double double in Hercules
« on: August 28, 2017, 01:15:59 PM »
These last few nights have had really good seeing, and I've been chasing doubles in Hercules (my yard has a better view to the west, so that's where I'm usually looking).  12.5-inch f/7, 553x

There were many "wow" objects, of which following is a selection.  I end below with a challenging "double-double" I feel really lucky to have seen:

STF 2107: !! Plotted in Cambridge Double Star Atlas, and I didn't expect it to be special.  Yellow and orange pair, very close ~1.5", 1 delta mag.  Very pretty. [AB seen, AC nearly 12th mag and super wide]
16H 51M 50.10S +28° 39' 58.7" P.A. 106 SEP 1.39 MAG 6.90,8.50 SP F5IV DIST. 58.41 PC (190.53 L.Y.)

STF 2095: Nice!  Yellow and white pair, 2 delta mag, 4"
16H 45M 05.23S +28° 21' 28.9" P.A. 163 SEP 5.2 MAG 7.36,9.16 SP F7III DIST. 215.98 PC (704.53 L.Y.)

STF 2103: Nice! Pretty bright white A, much fainter ~5 delta mag B, well separated, looks like a planet. [AB seen.  AC & AD fainter and wider]
16H 49M 34.67S +13° 15' 40.3" P.A. 44 SEP 5.2 MAG 5.93,10.00 SP A1V DIST. 100.1 PC (326.53 L.Y.)

52 Her = BU 627:  !! Very bright white star with a companion disk 2” out, 4-5 delta mag.  Wow!  B illuminated by A, as if it was a planet.  [A,BC seen.  BC is an equal pair only 0.3” separation – maybe try with the 20-inch.  7 stars total in the system.]
16H 49M 14.21S +45° 58' 59.9" P.A. 39.6 SEP 2.09 MAG 4.84,8.45 SP A1V DIST. 55.25 PC (180.23 L.Y.)

D15: Light orange & elongated with notch, near equal.  [0.9” at discovery, 0.56” now]
16H 43M 56.29S +43° 28' 31.2" P.A. 332.8 SEP 0.56 MAG 9.04,9.27 SP K5 DIST. 27.03 PC (88.17 L.Y.)

HO 557: !! B only visible with averted vision.  As I drift from averted back to direct the star fades and I can only hold direct for a moment before it disappears.  Very interesting effect.  ~5” and 4 delta mag.
17H 13M 57.81S +16° 21' 01.0" P.A. 322 SEP 4.2 MAG 8.57,12.00 SP F8 DIST. 106.27 PC (346.65 L.Y.)

PRY 2: Blue-white and slightly reddish B, 3-4 delta mag, 1.5”.  Not hard at all!
17H 04M 41.34S +19° 35' 56.7" P.A. 227 SEP 1.8 MAG 6.19,9.29 SP A0IV DIST. 176.68 PC (576.33 L.Y.)

BU 822: Bright orange star with a consistent pin-prick point of light, stays still in occasional seeing shimmer.  Fainter than PRY 2's B.  1.5”.  Same PA as PRY 2's.  [AB seen; AC is super-wide & 11th mag]
17H 03M 52.67S +19° 41' 25.8" P.A. 227 SEP 1.4 MAG 6.58,9.89 SP K4III DIST. 229.89 PC (749.9 L.Y.)

These last two are close enough together I tried them as a double-double.  The trick is to maintain enough magnification to be able to keep the splits.  I went down to 277x 0.4° TFOV and could just squeeze the two within the field stop.  PRY 2 remained a very clean / clear split, while BU 822 was more challenging due to B being half magnitude fainter and slightly closer separation than the PRY 2 pair.  I could split BU 822 at 277x when in the center of the field, but I needed to wait for seeing to perfect and to bring it in a little from the field stop to avoid edge distortion.  But, for a few moments, I had these two in view as a double-double.  I'll try this again at CalStar in the 20-inch, it should resolve nicely.  Given the distance between the two pairs, they are just a line of sight double-double, but nice all the same.

4
TAC Visual / Re: Congrats Mark McCarthy!
« on: August 28, 2017, 01:08:46 PM »
I hope the list change doesn't put you behind your goal; though I would think the AL would accept your observations regardless -- especially for such challenging objects!  I will definitely be giving Gomez's Hamburger a try at CalStar, thanks for the tip!

5
TAC Visual / Re: Congrats Mark McCarthy!
« on: August 27, 2017, 04:42:02 PM »
That's odd, Peter.  I don't find that object on any of their lists (https://www.astroleague.org/al/obsclubs/planetarynebula/planetneb1.html scroll down for file links). 

Maybe it was taken off the list at some point?

Maybe rules changed too?  I did all 110 of the standard list and all 26 of the alternate list (though only the 110 are required, the alt is if your latitude is too far north for all of the standard list).  I only submitted my visual descriptions, no sketches (though I did make awful field scribbles in my notebooks).

There are some real toughies in the alt list:

EGB 1: Rather large but extremely faint glow, no central star, seen with OIII & averted vision only; difficult

HDW 3 (HaWe 4): Impossible to see without OIII.  Higher magnification is too narrow a FOV, 205x worked best.  Large and irregularly shaped, excessively faint, diffuse / ragged edge.  Many faint stars in field, not certain which is CS.

PuWe 1: Purgathofer & Weinberger / 1980 discovery PN in Cam: Excessively faint, -- seen only as a gray scale change, a brighter dark than the dark sky.  UHC works, OIII too.  Irregularly round, very large, with mottling.  @ 87x.

6
TAC Visual / Re: Congrats Mark McCarthy!
« on: August 27, 2017, 09:04:56 AM »
Thanks for the recognition!  This explains the number of Herschels and PNs in my ORs over the last couple of years.  I admit to having list fatigue toward the end, but will probably pick up another AL list soon -- they're great as a learning tool for beginners and helped me become a better observer.

7
TAC Visual / Re: Experienced Eclipse Chasers. Your input please.
« on: August 02, 2017, 04:31:07 PM »
I'm no expert, but I thought this was a good description of what will happen

http://www.eclipse2017.org/2017/what_you_see.htm

8
Observing Reports / Re: Speaking of subtle...
« on: July 27, 2017, 12:12:46 PM »
I guess I have gone off the "deep" end, haven't I...    ;)

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Observing Reports / Speaking of subtle...
« on: July 26, 2017, 08:41:33 PM »
There were a couple of other observations the other night at Pinnacles which intrigued me.  I was observing “without a list” and just seeing what I could find on the chart, so I saw these without knowing what they were beforehand:

GN 18.32.5 = PNG 27.0 +1.5, 18 35 11.6 -04 29 06.  Using 333x, the nebula sprouts to the SW of a relatively bright star, but is only seen with averted vision and OIII.  It is a diffuse, extremely faint small cloud which brightens near the star and fades to a round diffuse edge.  Searching the internet, I find one other observation from a German observer using a 27-inch; his sketch shows the object much brighter than what I saw*.  Simbad calls it a reflection nebula but it is plotted as a PN. 

Sherwood 1, PN, = Sd 1 = K 3-77.  Plotted in Interstellarum at the eastern edge of LDN 889, which is is part of the Gamma Cygni nebula complex.  I had to star hop from Gamma around this blank space in the sky to get to Sherwood 1, as it was labeled.  At 333x and only with OIII, a very small, excessively faint round shell with diffuse edges swam into view, held 50% with averted vision.  Very low surface brightness and no central star.  Very close star just to the ESE.  After getting home and searching for the object online, I found the discovery paper by William A. Sherwood who, as a graduate student in 1969, was blinking photographic plates at the Royal Observatory in Edinburgh.  I precessed the 1950 discovery coordinates and searched the result in Aladin, which confirmed the observation for me as my sketch matched the star field.  Distance: 18000 ly.  17.2 mag, 7.0” size.  Today I received Kent Wallace’s excellent (or better yet, monumental) Visual Observations of Planetary Nebulae book, and I find his observation in a similarly sized telescope revealed a faint stellar object, though I was 100x higher in magnification.  I observed this during the “peak” seeing and transparency period during our time at Pinnacles, so I believe that helped.

J014709+463037 = Andromeda's Parachute.  This object was noted on Deep Sky Forum** earlier in the week, a gravitationally lensed quasar with an incredible red shift z=2.377.  I printed some AAVSO charts and gave it a try.  But, now it was 2am and the good seeing window had closed, and the sky began to haze.  I spent almost a half hour in the field searching.   Unfortunately my charts were confusing, and I could not very well match the star fields with the eyepiece view, though I was very certain my star hop was correct.  In any case, there are better charts available at DSF now, so I hope to try again at CalStar.

* http://www.deepsky-visuell.de/Zeichnungen/GN18_32_5.htm
** http://www.deepskyforum.com/showthread.php?1036-Newly-discovered-quadruple-quasar-candidate-in-Andromeda

10
"And what about the huge (roughly 25' in size), low surface brightness HII region Sh 2-72? Is this a visual object?"

Yes, it is. 

I observed it last night from the Pinnacles with my 20-inch, after first observing NGC 6749 (@ 205x a fairly large but very faint irregularly round glow, with slightly more concentration in the middle, just distinguished from rest of field) & Sh 2-71 (205x w/ OIII, pretty large 3:2 N-S, fairly bright, with ragged edges; presumed central star noticed with averted vision then held direct.)

Sh 2-72: Using HBeta filter at 101x 3.1 exit pupil, I could discern very faint mottling in the field and scanning about the adjacent areas, with a line of distinct crenellations along the eastern edge of the glow -- the edges of the nebula set off against the darker sky background.  Averted needed to brighten the view but it could be seen direct vision.  At 87x 4.4 ep, the mottling was maintained within the larger 1° field.  UHC had a similar but somewhat weaker effect.  Surprisingly not too difficult, considering transparency and seeing were about average.

Thanks to Mark Wagner for the confirming view

11
As I recall the visitor's center has an outside light on all night, and it shines into the parking lot.  Suggest one of the club people ask the ranger if it can be turned off, or bring something to shield it.

12
Observing Reports / Legitimate Peak observations
« on: June 28, 2017, 10:50:10 PM »
So, to prove I was doing more than just seeing weird things in the sky last Friday night, here’s some of the other observations.  I did mostly free-range observing, just picking an area of the sky and finding what I could from my chart.  Starting out with various DSOs around Vega:

MCG+6-41-6: Small, very faint, slightly elongated with an irregularly bright core. [14.6B, 0.667” x 0.560”, 370mly]

NGC 6685: Very faint, small, stellar nucleus, slightly elongated N-S.  With IC 4772 to the north, extremely faint, round and very small.

NGC 6675: Moderately large and bright, brightens with averted vision, especially the central part.  No distinct core or nucleus.  Oval with diffuse edges.  3-2 NW-SE.

NGC 6663: Very faint, irregularly bright, irregularly shaped oval patch.  Near STT 356.

NGC 6646: Moderately large, fairly bright, round-to-oval, brightens with averted vision.  IC 1288 to NE, small elongated 3:1 N-S, brighter in middle.

UGC 11228: Just stellar nucleus and very small faint oval halo [LINEAR type active galaxy nucleus. 14.5B, 1.013”x0.689, 265 mly]

NGC 6703 & 6702: 6703 is Brighter, with bright core and diffuse halo, mostly round -- spiral? in an arc of stars.  6701 is smaller, fainter, round, with a brighter core and elongated halo with averted vision.

NGC 6711: Fairly faint, need averted vision to notice it.  Small. Seems to have two brightenings in the diffuse oval halo SE-NW.  -- it's a face on spiral which accounts for the brightening -- these are the arms.

UGC 11376: Very faint, averted vision needed; small oval glow. [14.3B, 0.84”x0.386” 299 mly]

NGC 6742: PN.  Fairly uniform small smoke orb, a little brighter on the south side.  No central star.  A little better with OIII, 205x

NGC 6732-1 & -2: Two glows.  One to south (-1) is brighter and slightly elongated W-E; other is faint and very diffuse, no core.

Watson 2, open cluster: Seen as a small star clump in the 80mm finder.  In the scope it is a poor group a half a degree large.  Seems a double is in the middle of a group of stars forming a square and some others scattered, all similar brightness and no nebulosity.  Orange star makes the SW corner of the square.  Not listed in Archinal's Star Clusters book

STF 2368: Near equal white, close, ~1.5".  Hair split at 205x, clean at 333x.  To SSE is a faint green-blue star further south. P.A. 320 SEP 1.9 MAG 7.63,7.77

UGC 11292: Extremely faint small glow with star superimposed; oval very diffuse. [14.3B, 0.7” x 0.47”, 379 mly]

UGC 11202: Excessively faint glow, small oval with some stars involved. [14.4B, 1.103”x1.015”. 361 mly]

HU 674: Split with seeing at 333x, near equal white. (!! 0.47", my first double under 0.5" separation, woohoo!) P.A. 208.6 SEP 0.47 MAG 7.68,8.63

After a break I went to Gamma Cygni and have a look around, using the detail star chart in Interstellarum.  A number of very close pairs, and some exotic planetary nebulae.

STF 2606: Close pair 2 delta mag. 333x (!! AB 0.67") P.A. 146.6 SEP 0.67 MAG 7.74,8.43

KjPn 1: PN. Stellar, blinks strongly with OIII.   333x

KjPn 2: PN.  Nearly stellar, blinked with OIII as a bloated green star. 333x

KjPn 3: PN.  Stellar, green with OIII and blinks slowly, very small disk 333x

STF 2663: ~5" equal magnitude white [AB seen, there are 5 visible; P.A. 324 SEP 5.4 MAG 8.2,8.66].  There is another double to the south!!  A very beautiful & delicate pair, dull orange and dull yellow, 3 delta mag, ~3".   Frustratingly I can't find it in Aladin... Does not seem to be part of the STF system

Kro 76: Plotted as an open cluster, but is it just a double?  Orange and very faint 4 delta mag B, PA to the south, ~2-3", plus another extremely faint star due west about 6"

NGC 6874: Large open cluster, fills half degree field, generally triangular shaped, rather rich with a wide range of brightness.  Nice.

And then I came to STF 2609, and the weirdness set in…

13
Observing Reports / What the heck was that?
« on: June 24, 2017, 09:02:40 AM »
At the risk of bringing ridicule and shame upon my head, I want to relate an observation I made last night while at Fremont Peak, because I can't figure out what it was.

I was using my 20-inch, around 2:30am, with Cygnus at zenith.  I was poking around the Cygnus Cloud observing a variety of objects, when I come to STF 2609.  Instead of the fairly close pairing I expected, I see two streaks of light, each maybe 10" long, each with bright small disks on the ends.  They looked like staples.  They were parallel to each other and N-S, one was a little dimmer and shorter than the other, and each had a dimming along the major axis between the points at the end.

I thought it was some kind of optical defect, but the streaks remained at all powers I tried (205x, 333x, 533x, 667x).  Other stars were points of light, even those of similar magnitudes.  I took a few minutes break and came back to it: the same.  Seeing was very good; just a few minutes before I made a clean split at 333x of B1289, which has a 0.7" separation.  Transparency was average; SQML was 21.2

STF 2609 is 6.69/7.64, 1.9", PA 21°.  I would say the streaks were of similar brightness, separation, and in the correct PA.  But why in the world would they be stretched out so?

14
TAC Visual / Triple double with Cor Caroli
« on: June 14, 2017, 12:56:46 PM »
While hunting faint and close pairs with my 12.5-inch last night, I realized there is a "triple double" which includes Cor Caroli!  They're not all physically bound to each other, but it was a nice scene all the same.

Cor Caroli = STF 1692 is the well beloved Alpha Canum Venaticorum and was the start of my star hop for the list of pairs I prepared for the session.  About half a degree to the west was STF 1688, a faint pair (9.24/11.06, 14.4", 343°), yellow A and orangish B, which I identified using 340x.  Next on the list was STF 1702, which was about half a degree to the east of Cor Caroli.  It was a wide orange-yellow pair, 8.72/9.41, 36.1", 82°.

It struck me it might be possible to see all three in the same FOV, so I went down to 71x and 1.1° and yes, I could just squeeze all three in the view, the two fainter Struves just within the field stop on either side of the showpiece in the center.  It helped to have already seen STF 1688, since it was the faintest pair to pick out.

It's these little scenes which give me great satisfaction while observing.  Hope you have something new to look for when observing this old favorite.

15
Observing Reports / Re: Making the most of it from the Peak
« on: May 31, 2017, 12:35:19 PM »
I'll give Bob the benefit of the doubt.  I was at 205x, which is ok for all those galaxies I was viewing, but I should have lowered it for this PN.  In the caption to his sketches Bob mentions using only 64x--so perhaps my higher magnification spread out the shell making it appear fainter, vs. more concentration in lower magnification.  I had more aperture (his 15-inch vs. my 20-inch), but he might've had a darker and more transparent sky -- I observed this toward the end of the session when I was viewing through gaps in clouds.

Worth another try to see if the view improves.

Besides, Reiner Vogel calls this "not overly difficult," albeit with a 22-inch, in his excellent large PN observing guide.  http://www.reinervogel.net/pdf/Large_PN.pdf

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