I have recently returned from three superb nights at Zephyr Ridge Observatory, where I was treated to crystal clear and generally steady skies.
In my last post I mentioned that dedicated visual observers often push the limit of their eyes and telescope aperture, regardless of how much aperture one has. This trip was very much about doing just that, and my particular focus – aside from a few exceptions to provide variety – was a selection of challenging planetary nebulae.
The term “planetary nebula” was coined by the famous observer William Herschel, and it is a confusing misnomer as these objects have nothing at all to do with planets. Herschel observed the nebula NGC7009 and the small round nebula looked to him like a planetary disk, and so the class of objects known as planetary nebulae came to be. We now know that such a nebula is the result of end-stage physical processes occurring within a star that result in the expulsion of a portion of the stellar material. The material is driven outward, and the remnant star generally becomes a white dwarf, the so-called central star of the nebula.
The summer sky in the northern hemisphere has some fine examples of planetary nebulae, with M27, the Dumbbell Nebula, and M57, the Ring Nebula, being the most prominent. I have enjoyed these objects many times in my observing experience, and have even glimpsed the difficult central star of the Ring Nebula on more than one occasion. But, on this trip I came prepared with a list of planetary nebulae that I knew would test my eyes and my 20” aperture. Some of these objects were kindly provided to me by Ted Forte, the chairman of the Planetary Nebula Club of the Astronomical League. I added two dozen more to his list from my own research, and over three nights I managed to observe most of the combined list.
It was a rewarding experience to attempt these challenging objects. My report will seem at times like a broken record as descriptions like difficult, tiny, barely seen, only seen with averted vision, intermittently visible, and the ultimate failed to see it at all seem to repeat over and over. Yet, each of these planetary nebulae contributed to the overall experience for me in its own unique way, and I feel a sense of accomplishment in seeing so many of these “broken stars.”
I mention two highlights. The first is that I was able to successfully observe Pease 1, the well known and challenging planetary nebula located within the fine globular cluster M15 in Pegasus. I first attempted this observation in 2009, but failed to see it. This time I succeeded, and it was quite a surprise to see the bright pinpoint of light blaring from an unresolved mass of stars near the globular’s core, thanks to the magic of an OIII filter and steady seeing.
While being able to see a planetary nebula within a globular cluster may be an observing pinnacle for most amateur astronomers, Pease 1 was actually not the most difficult object I attempted on this trip. I am not sure which I would choose as the most challenging of the bunch, but in my report below I do note several cases of objects that I could not see at all. I will try those again some day; as with Pease 1, a second attempt may prove successful.
A far less challenging but very impressive sight was the beautiful Iris Nebula, NGC7023, in Cepheus. Since this nebula has a very bright, centrally located star, I can imagine how someone could mistake this for an exceptional planetary nebula with an obviously visible central star. However, this is not the case; the centrally located star is quite young and quite in tact, and is merely illuminating the cloud around it. The Iris Nebula is therefore a so-called reflection nebula. This one is well worth attempting for those with at least moderate aperture telescopes.
I follow with my observing logs. I hope these will inspire you to try to see some of these offbeat planetary nebulae. If not, there are plenty of brighter ones to contemplate, including the Dumbbell and Ring Nebulae. Although my report does not formally mention these, I did pay visits to each, just to enjoy their magnificence one more time. They never disappoint.
Observing Logs: All observations made with my 20” f/5 reflector.
7/27/2011 10:54 PM
Hickson 73 Galaxy Cluster Boo Mag 13.3 (brightest)
RA 15h02m40s Dec +23°21’13” size (of NGC5829) 4.8’
Calm and clear. Excellent seeing. Hickson 73 happened to be quite a difficult group, especially as the first observation of the evening. At 98x I was able to locate this group using a Voyager map, and immediately detected a small glow in the field. I switched to 363x. There is a fairly bright field star, with a fainter one 3 or 4 arcminutes to the east. In between these, I saw a hazy patch of light with direct vision (NGC5829), but it was quite faint, and even with averted vision I could not see any central condensation or discernible shape to the halo. Just to the NNW of this galaxy, I was able to barely pick up a small fuzzy patch that is IC4526, which was intermittent with averted vision. My map showed other members of the group nearby, but I was unable to see them. I also slewed further away to the north to see if I could detect PGC1690334, which was shown on my map, but I failed to see anything in the indicated location.
7/27/2011 11:09 PM
NGC5754 Group Galaxy Cluster Boo Mag 14
RA 14h45m20s Dec+38°43’54”
This group was not as difficult as Hickson 73, observed just before, but it was still challenging. At 363x, the largest and brightest member was NGC5754, which presented as a faint circular glow with a brighter core and a stellar nucleus. Just to the west of this galaxy, I could intermittently see with averted vision a small point of light, which I identified as NGC5752. Quite difficult. Moving to the NNE of NGC5754 there is a faint field star, and just NW of this star I saw another small, faint patch of light which is NGC5755. Also very faint, but once found I could see it with direct vision. There is also a tiny point of light just to the NW of this galaxy, which was extremely faint and intermittent with averted vision. This is NGC5753. My map showed two more galaxies separated from this main group to the south, and these two galaxies are located in between two prominent field stars, making them easy to locate. These were PGC2131540 and PGC2130996. Unfortunately, I was not able to see these galaxies. So, I saw four members of the group, NGC5754 being the brightest, followed by NGC5755.
7/27/2011 11:32 PM
PK024-05.1 or Minkowski 4-11 Planetary Nebula Sct
RA 18h54m18s Dec -10°05’00”
I obtained good views of this nebula at 212x and 363x, but could pick up the field stars more easily at 363x. At 363x, this nebula is visible without a filter. It is a small disk, located in the middle of a group of field stars, with a clump of 4 stars just to the WNW and 3 stars just to the ESE, with two of these seeming to touch the edge of the nebula, one of which is quite faint. The nebula itself is visible without filter as a small circular disk, gray in color. Central star not visible. I tried both OIII and UHC filters, and preferred the UHC. With this filter in place, the contrast was improved so that the edge of the nebula was more clearly demarcated. Only two of the aforementioned field stars were still visible with the filter in place. A rewarding object.
7/27/2011 11:55 PM
PK017-10.1 or Abell 51 Planetary Nebula Sgr mag 13.5
RA 19h01m01s Dec-18°12’16” Size 1.12’x0.97’
Quite difficult. I used a Voyager software map to verify the precise position. Without filter, I could see nothing at 98x and 212x. With OIII filter, at 98x I could intermittently discern with averted vision a very faint disk of moderate size. It was elusive, but I saw it repeatedly. I switched to 212x and OIII, and was unable to see it with this combination. So, I switched back to 98x and noticed that the field stars seemed a tiny bit dimmer, so I believe the object – which was already at quite a low altitude in the southern sky – had dipped into a less transparent region of the sky. So, I was unable to repeat the original 98x observation. But, I am certain of my initial sighting. This object would be better seen at a more southerly latitude.
7/28/2011 12:27 AM
PK051+06.1 or Kohoutek 1-17 Planetary Nebula Sge
RA 19h03m36s Dec +19°21’00”
This object is challenging. I used a Voyager map to confirm the precise location. At 212x, it was not visible without filter. With an OIII filter, I saw a moderate-sized circular disk (maybe 20-40 arcseconds in diameter). I could hold it in view with averted vision once I pinpointed the location. Central star not visible.
7/28/2011 12:54 AM
PK068-02.1 or Henize 2-459 Planetary Nebula Cyg
RA 20h13m54s Dec +29°34’00” Size 5.0″
I tried to see this, but failed. I used a Voyager map to confirm the precise location. I used 212x and 363x with and without an OIII filter, but was unable to see it.
7/28/2011 1:18 AM
PK 111+11.1 or DeHt5 Planetary Nebula Cep Mag 12.5
RA 22h19m36s Dec +70°56’00” Size 8.8′
I tried to see this, but failed. My data suggests this is rather large, so I used 98x with and without OIII, with location confirmed by a Voyager map. At times I thought I glimpsed a vague glow, but I was not convinced by the sighting, and so consider this a negative observation.
7/28/2011 1:38 AM
PK100-08.1 or Me 2-2 Planetary Nebula Lac Mag 11.9
RA 22h31m42s Dec +47°48’00” Size 5.0″
I used a Voyager software map to confirm the precise location. At this location there is a very tight row of three stars, the easternmost of which is the planetary nebula in question (according to the map). The westernmost appeared to be roughly equal brightness to the PN, whereas the middle star in the row is substantially fainter. All this is with unfiltered view at 212x. I inserted an OIII filter, and indeed the easternmost star remained quite bright, while the westernmost star dimmed substantially and the middle star disappeared altogether. So, this confirms the sighting: a stellar planetary nebula, white in color.
7/28/2011 1:57 AM
PK118+08.1 or Minkowski 2-56 Planetary Nebula Cep Mag 12
RA 23h56m36s Dec +70°49’00”
I tried to see this object, but failed. I confirmed the location with a map printed from Voyager software. I tried 98x, 212x, and 363x with and without OIII filter, but could not see anything.
7/28/2011 2:14 AM
NGC7023 Iris Nebula Reflection Nebula Cep Mag 7
RA 21h01m36s Dec +68°10’10” Size 18’
Viewed at 212x. This is a lovely nebula. My report is based on an unfiltered view; I tried the OIII and UHC filters, and the UHC was marginally useful, but I preferred the view without any filter. The nebula is anchored by a very bright star that is centrally located, identified as V380 Cephei, a young (5000-6000 years old) and bright star (180 solar magitudes of luminosity). The nebula is large, exhibiting a bright glow that diffuses gradually into the background so that the full extent is likely much larger than the brightest area that I could see. The shape is irregular, but it surrounds the star and seems to extend outward a little more to the west side. Using averted vision, I was able to see a prominent extension of the nebula to the south that contained a dark protrusion that entered the extension from west to east. The immediate and obvious sighting of this extension with averted vision was quite startling, as it is not apparent with direct vision. A beautiful nebula.
7/28/2011 2:35 AM
NGC6842 Planetary Nebula Vul Mag 14
RA 19h55m02s Dec +29°17’20” Size 0.8’
This planetary nebula was easy to spot without a filter. At 363x, I was able to see the central star. It is quite faint, but I could hold it for extended periods with averted vision. The nebula is fairly good-sized and circular. Three field stars hug the S-SE border of the nebula. I also detected a very faint star near the edge of the nebula to the NE. With OIII filter, there is some contrast improvement, and in particular I noted that the edge of the disk seemed rather ill-defined – not smooth and clearly demarcated.
7/28/2011 2:54 AM
PK068+01.2 or Henize 1-4 Planetary Nebula Cyg
RA 19h59m18s Dec +31°54’00”
I found this initially at 212x with OIII filter. It is located just north of a bright field star, which seems to be hugging the south edge of the nebula. At 363x I could see the nebula without the OIII using averted vision. At 363x with OIII, the view is enhanced. The nebula is elongated with the long axis oriented approximately N-S, with the field star attached to the south side of the long axis. The perimeter of the nebula is well-defined. Central star not visible. Gray color.
7/28/2011 3:07 AM
PK056-06.1 or Kohoutek 3-51 Planetary Nebula Sge
RA 20h02m36s Dec +17°36’00”
I navigated to the precise location using a map printed from Voyager software. At 212x and especially at 363x, the nebula appeared as a tiny nonstellar fuzzy glow, visible with direct vision and no filter, although quite faint. No central star visible. The color was gray. Inserting an OIII filter confirmed the sighting, as the nebula remained bright while surrounding stars dimmed, although strangely the filtered view seemed to diminish the extent of the disk, as the nebula seemed slightly smaller. Perhaps the outer edges of the gas do not respond well to filtration – or my eyes were playing tricks at this very late hour.
7/28/2011 10:43 PM
Hickson 78 Galaxy Cluster Dra Mag 14.4 (brightest)
RA 15h48m28s Dec +68°12’28”
Fine conditions this night, as I began my session with this galaxy cluster. I was able to see three of the four members of this cluster. The easiest was UGC10057, which is the largest galaxy. It was faint and had uniform brightness and was slightly elongated. Just to the SSW of this galaxy there was a smaller fuzzy patch with a bright core and suspected stellar nucleus (still a little breeze blowing making the view a little jumpy). This is PGC56067. My map identifies a star superimposed on this galaxy (GSC 4412-0236), so my suspicion of a stellar pinpoint within could be this star rather than a characteristic of the nucleus of the galaxy. Returning to UGC10057 and directing attention slightly to the NE of there, I saw a tiny pinpoint that was very faint. I believe this is PGC56086, even though I could not see a hazy halo suggesting a galaxy. There is a field star shown on my map in this general direction as well, but I saw this in the field and it is located beyond where I detected the tiny pinpoint that I believe is PGC56086. The fourth member, PGC56095, was not visible.
7/28/2011 11:04 PM
Hickson 80 Galaxy Cluster Dra Mag 14.8 (brightest)
RA 15h59m12s Dec +65°13’33”
I found this group at 212x directly south of a tight N-S oriented pair of field stars. Just south of the pair of stars I could see a hazy clump. I examined the cluster at both 212x and 363x, preferring the view at 212x. I was able to pick out three distinct concentrated areas of light amidst the very faint cloud. The two field stars point directly to two galaxies on the east side of the cloud, arranged N-S, PGC56590 and PGC56588. These appeared as two tiny fuzzy spots, with no other detail visible. I also believe I saw PGC56572, which was an intermittent point of light. PGC56577 was not visible. Note that the latter two galaxies are so close together that I may have misidentified which I was able to detect, but I believe I got it right.
7/28/2011 11:19 PM
Abell 2147 Galaxy Cluster Her Mag 13.8 (brightest)
RA 16h02m17s Dec +15°54’43” Sep 68.3′
I toured this group at 212x. I began in the center of my map, which showed an apparent double star, with the easternmost member being substantially brighter. To the west of this pair and heading northward, I saw at least four galaxies, all faint. The most prominent is UGC10143, the furthest north of the four faint fuzzies, which was the largest and brightest and had an elongated halo. From here I slewed to the SW where there are a number of PGC galaxies shown on my map. I was not able to see any of these, but noticed another galaxy nearby to the SE, which I identified as IC1165. IC1165 is a small circular haze, within which I intermittently glimpsed a stellar pinpoint that was off-center. My map shows IC1165B next to IC1165, but I am not sure whether I saw evidence of the companion galaxy or merely a superimposed field star. From there I slewed WNW a short distance arriving at an asterism of four stars. Just to the SW of the westernmost member of this asterism I detected a very faint point of light where galaxy PGC100398 is located according to my map. From there I slewed NNW and saw a tiny spec of light just west of a five-star asterism where PGC56838 is located. Averted vision enhanced the view of this, as I could see a little haze rather than just a point. Moving north from there, I panned around and found the precise location of galaxy PGC56781, where I could barely pick up a faint point of light that was quite elusive and unreliable. Moving north from there, I saw a small hazy patch (UGC10144) with a tiny companion patch of haze next to it (PGC56786) located NW of a bright field star. UGC10144 is definitely the brighter and larger of the two, with a small amount of central brightening. From there, I slewed westward to seek other members, but was not able to see anything else.
7/28/2011 11:55 PM
PK 040-00.1 or Abell 53 Planetary Nebula Aql Mag 16.9
RA 19h06m46s Dec +06°23’56” size 0.52’x0.45’
This is a negative observation of this planetary nebula. I used a Voyager map to confirm the precise location, but at both 98x and 212x – with and without OIII filter – I was unable to see it.
7/29/2011 12:14 AM
PK049+02.1 or Henize 2-428 Planetary Nebula Aql
RA 19h13m06s Dec +15°47’00”
This is a very difficult object. It is located within a rich star field, and it took some doing to find a suitable series of asterisms to pin down the precise location, but I did succeed based on my Voyager map. At 212x without filter, I was able to barely see a “soft” star that, with averted vision, seemed to be nonstellar. Once found, I could hold it with averted vision, especially if I slowly slewed the telescope. The response to OIII filter was weak to modest. I was able to see a little more of the disk, clearly nonstellar, and the fact that the nebula stayed bright while nearby stars dimmed confirmed the finding. No color, and no central star seen.
7/29/2011 12:37 AM
PK029-07.1 or LSA1 Planetary Nebula Aql
RA 19h13m54s Dec -06°19’00”
Once again, I navigated carefully to the precise location with the help of a Voyager map. At 212x with no filter, I was able to see a small nonstellar disk that was fairly challenging. Averted vision showed the nonstellar nature much better than direct vision. Adding an OIII filter, I could see the nonstellar disk with direct vision. I also tried a UHC filter, which also improved the view, and it was similar to the OIII. I think the view with the OIII was slightly preferable. At 363x and OIII, the view was also very good. Nonstellar, gray disk. No central star was seen.
7/29/2011 12:57 AM
NGC6772 or PK033-06.1 Planetary Nebula Aql
RA 19h14m36s Dec -02°43’00”
This nebula was a welcome relief from the more difficult objects I have been viewing this week. At 212x with no filter, the nebula was obvious with direct vision. It was reasonably large. At 363x and no filter, I was unable to see a central star, but there were some very faint stars on the east side of the halo, with one seemingly overlapping. The nebula was mottled with irregular perimeter. I tried 363x and 212x with both UHC and OIII filters, and preferred 212x with UHC, although the differences were slight. At 212x with UHC, the contrast was improved. The mottling was still evident, and averted vision suggested slight thinning of the gas towards the center, suggesting possible annularity. The nebula was roughly circular, although after long examination, it may be slightly stretched in the N-S direction. Overall, the brightness of the gas was not uniform, and if I had to pick, I would call the north side a little brighter than the south, but the difference is slight.
7/29/2011 1:17 AM
PK058+06.1 or Abell 57 Planetary Nebula Vul
RA 19h17m06s Dec +25°37’00”
This object was not visible without OIII filter. I used 212x and found it with the help of my Voyager map, first detecting it with averted vision. It is a moderate-sized disk, easy to hold with averted vision. Once found, I could see it with direct vision, but better appreciation required averted vision. It seemed circular, and I saw no central star. There is a fairly bright field star just to the SE, which was a useful signpost for finding the nebula.
7/29/2011 1:34 AM
PK059-18.1 or Abell 72 Planetary Nebula Del mag 13.8
RA 20h50m02s Dec +13°33’28” 2.23’x2.02’
This nebula was not difficult to find, as it is located just east of a very bright star. I could barely detect a vague glow near that star at 98x with no filter, but adding the OIII brought forth the nebula more clearly. The shape was irregular and it was of moderate size; it looked more like a reflection nebula than a typical planetary nebula. There are quite a few stars involved besides the bright star just mentioned. There are three bright stars just west of the nebula, and two more to the NNE. There is another star inside the nebula, but the irregular shape of the gas and the star’s location within made me question whether this could be the central star. I increased the power to 212x, with and without filter, but the view at 98x was better.
7/29/2011 1:54 AM
PK103+00.1 or Minkowski 2-51 Planetary Nebula Cep
RA 22h16m06s Dec +57°29’00”
This nebula was easy to spot at 98x and OIII filter as a small disk. I tried 212x and 363x, and I preferred 212x. At 212x I could not see it without the OIII filter. It is a roughly circular gray disk, maybe half an arcminute in diameter, with an irregular perimeter. Central star not visible.
7/29/2011 2:04 AM
PK116+08.1 or Minkowski 2-55 Planetary Nebula Cep
RA 23h31m54s Dec +70°23’00”
I spotted this easily using 212x and OIII filter. It is also visible with direct vision without filter as a moderate-sized disk, although a somewhat incomplete disk as there is some thinning of the gas on one side. Central star not visible. There are two bright stars to the east, the closest just ESE of the nebula and it has a fainter companion. The other is NNE of the nebula and a little further away. With OIII filter, I saw a smooth, well-defined disk of moderate size.
7/29/2011 2:40 AM
Pease 1 (within M15) Planetary Nebula Peg Mag 15.1
RA 21h30m00s Dec +12°10’00”
I used detailed finder charts from www.blackskies.org to aid in finding this nebula. The seeing at this time was quite stable, so I could comfortably work at 500x. I followed the prescription on the charts, first finding the indicated trapezium of four stars, then star A, then star D, and finally star E. Beyond star E, the next step led to an unresolved clump of stars near the edge of the core of M15. I tried to resolve something there, but could not. But, I knew I was in the correct area to find Pease 1. So, I inserted an OIII filter and viewed the same clump of stars. Using averted vision, to my surprise, I was able to see a bright point of light within the unresolved mass (the mass itself was dimmer). It was intermittent, but I was often able to hold it in view for substantial lengths of time. I repeated the observation, by removing the filter and verifying that I could not see such a point of light within the region in question. Reinserting the OIII, I was able to verify the bright point again, and so I am confident of the sighting.
7/29/2011 11:28 PM
PK084+01.1 or Kohoutek 4-55 Planetary Nebula Cyg
RA 20h45m06s Dec +44°39’00” Size 27″
Using a map from Voyager software, it was not difficult to pinpoint the precise location of this nebula. I tried 98x with no filter, and saw nothing. Likewise at 212x. Adding an OIII filter at 212x did not help either. At 363x with no filter, I was able to detect an extremely faint stellar point at the precise location. Once I saw it with averted vision, I could hold it with direct vision. Adding an OIII filter at 363x caused the point to disappear. Likewise for the UHC. I returned to 212x, and this time I could now see the stellar point. Also, at 98x I could now intermittently see the point with averted vision. Under no circumstance was I able to discern a disk. Since I verified the location with certainty based on my map, I conclude this is a stellar planetary nebula that does not respond to narrowband filters.
7/29/2011 11:55 PM
PK043-03.1 or Minkowski 4-14 Planetary Nebula Aql
RA 19h21m00s Dec +07°37’00”
This nebula is located just to the east of a small group of 8 stars. I tried various eyepiece and filter combinations, and ultimately preferred the unfiltered view at 363x, which gave a view of a very faint, gray disk that I could hold easily with averted vision and partially see with direct vision. I experienced difficulty using the OIII at 363x, as I kept losing sight of the nebula due to field drift, but I did glimpse it. So, I backed off to 212x (unfiltered), which showed a tiny disk. The OIII filter at 212x caused the 8 field stars to disappear while the nebula remained, with the disk seeming to be more focused but still nonstellar. None of the unfiltered views allowed me to see the central star.
7/30/2011 12:12 AM
PK048-02.1 or PB10 Planetary Nebula Aql
RA 19h28m12s Dec +12°19’00”
This nebula forms a slightly crooked right triangle with two bright field stars, and is directly south of one of these. At 363x I could see it as a small, gray disk – clearly nonstellar – and visible with direct vision. Both OIII and UHC filters offered contrast improvement, but I preferred the view through the UHC. With the UHC in place, the light seemed more concentrated in the center, with the edge more diffuse. This feature was subtle, especially given the tiny disk. Central star not visible.
7/30/2011 12:38 AM
PK044-05.1 or Kohoutek 3-36 Planetary Nebula Aql
RA 19h32m36s Dec +07°27’00”
I had some difficulty matching my map to the view through the eyepiece, but eventually I navigated to the exact location of this nebula. At 212x it is only barely visible. At 363x I could see a small nonstellar glow, barely visible with direct vision and best seen with averted vision. It is located very close to faint field stars; I could see 4 stars just next to the nebula, approximately to the west. No central star, and the image was a ghostly gray. Inserting an OIII caused the nearby stars to disappear and offered moderate contrast improvement, but did not change my overall description.
7/30/2011 1:04 AM
PK047-04.1 or Abell 62 Planetary Nebula Aql Mag 13
RA 19h33m18s Dec +10°37’01” Size 2.68’x2.52’
Very difficult. I used a Voyager map to navigate to the precise location, and the nebula is just SE of a rather bright field star. With no filter at 98x, I could only see 5 field stars where the nebula is supposed to be, but there was no sign of the nebula. With the OIII at 98x, I could see a rather large and extremely faint glow of irregular shape that encompasses the aforementioned field stars. I was able to hold the glow with averted vision but could not clearly discern the shape. None of the field stars seemed likely candidates for the central star.
7/30/2011 1:14 AM
PK017-21.1 or Abell 65 Planetary Nebula Sgr Mag 13.1
RA 19h46m34s Dec -23°08’12” Size 2.23’x1.23’
Very low altitude view, as I grazed the top of the south wall of my observatory. But, at 98x with OIII I could pick up this nebula right away as a large, diffuse elongated glow. The long axis is oriented NW-SE. There are some nearby field stars, including one off the NW end and another off the SE. I tried viewing it unfiltered at 98x, and could only make out an extremely faint glow. So, this is best seen with OIII, especially with averted vision although it is visible with direct vision as well. Central star not visible.
7/30/2011 1:38 AM
PK059-01.1 or Henize 1-3 Planetary Nebula Vul
RA 19h48m30s Dec +22°09’00”
I navigated to the precise location, and found what appeared to be just a star just to the south of a very tight double star of equally bright components that I was able to split. This stellar pinpoint appears to be precisely where the nebula is located according to my map, but the map also shows that the nebula is extremely close to a field star. There are two additional stellar points to the NE which form a roughly equilateral triangle with the nebula, and all are of approximately equal brightness. Inserting an OIII at 363x resulted in all three components of this triangle to dim, so I believe the stellar point is probably just a field star and not the nebula. With the filter in place, I was unable to see any evidence of a true nebulous glow, so I conclude that I probably was not able to see He1-3 on this night.
Note: Subsequent research suggests to me that I may have misinterpreted my map and expended my visual energy in the wrong location. I will try this again some day, as I think under good conditions I should be able to see a small nonstellar object.
7/30/2011 2:12 AM
PK062-00.1 or Minkowski 2-48 Planetary Nebula Vul
RA 19h50m30s Dec +25°55’00”
I had to work very hard to find this, but eventually was able to make sense of my map and the eyepiece view and navigated to the correct spot. There is a small equilateral triangle of stars of approximately equal magnitude. The nebula is located just north of the westernmost star of that triangle. I was able to glimpse it at 212x unfiltered as a small stellar point. At 363x it remained stellar and I could not hold it with direct vision, but could do so with averted vision. Inserting an OIII, I was able to intermittently glimpse a nonstellar glow, which was quite faint and elusive, but repeatedly seen. Challenging, but a reliable sighting.
7/30/2011 2:31 AM
PK084+09.1 or Kohoutek 3-73 Planetary Nebula Cyg
RA 20h04m00s Dec +49°20’00”
Once again, I used a Voyager map to confirm the location. At 212x unfiltered I was barely able to see the nebula. At 363x, the unfiltered view was a little easier. The seeing was a little unsteady at 363x, however, so I returned to 212x. At this power, using averted vision I could see a very small fuzzy disk, which I could hold with averted vision. There is a very small formation of faint stars forming an approximate equilateral triangle, and the nebula is located just west of the easternmost member of this triangle, with the star seeming to hug the eastern edge of the perimeter of the nebula. Inserting an OIII offered slight enhancement. Central star not visible.
7/30/2011 2:48 AM
PK112-10.1 or Abell 84 Planetary Nebula Cas Mag 14.4
RA 23h47m45s Dec +51°23’58” Size 2.45’x1.9’
This nebula is not visible without the OIII filter. At 98x with OIII filter, the nebula appeared as a fairly large and approximately circular glow. It is barely detectable with direct vision, so averted vision is required to really see it. A field star is located on the eastern end of the nebula, just on the edge of the gas. Central star not visible.
7/30/2011 2:57 AM
PK124+10.1 or EGB 1 Planetary Nebula Cas Mag 12.5
RA 01h07m08s Dec +73°33’24” Size 6’x3′
This nebula is very faint and required an OIII filter to see it. It is located to the SSW of a nice four-star trapezium. At 98x with OIII, it is a large glow of ill-defined shape that I could only hold with averted vision. No central star seen.
2 Responses to 7/31/11 Observing Report – A Survey of Broken Stars