[Pease 1] [M15]
(Please note that the dates shown above indicate when the reports were sent in, and may not reflect the actual observation date)
You can read Stephen's detailed report at his
"Faint Fuzzy Observations"
site - it may be too long to include here.
It does include excellent information on observing this planetary nebulae within M15. He has also observed the PN GJJC1 within M22 ! A link to that observation is also included on my PN site.
The weather in Holland doesn't provide very good conditions, but sometimes there's room for a nice surprise... I decided to search for the exact location of Pease 1 on this Thursday evening. The finder charts on this site gave me no problems finding the little trapezium. After that the starhop to the small group of stars lying northeast of M15 was not as hard as I expected it to be. After the starhop I saw a little blob of stars just northeast of the cluster and I knew I was on the right spot!
I relaxed for a few moments and went under my black 'blinking towel' to avoid every photon of light. I let M 15 drift through the field of a Nagler 7 (combined with a regular TV 2x barlow) wich gave me a magnification of 357. At first there was no sign of Peaase 1; with the OIII only the core of M 15 was visible and without the whole sparkling cluster appeared. After 15 minutes of blinking the blob of stars northeast of the core disappeared, except for a faint little 'star'. During the following minutes nothing seemed to be visible and the whole blob appeared and disappeared while blinking... But after few minutes (wich seemed to be hours...) the faint star appeared again and again! After more then 45 minutes I could draw the conclusion that I had caught the litte... I was quite a challenge, considering the Dutch skies! Pease 1 was hardly visible during the next evening, but the third evening confirmed my observations on the first night! Again I saw Pease 1 several times, but... after hard work at the eyepiece, because it's easier written than done!!!
During my observations I used a selfmade blinking tool. This made to job a lot easier and without the risk of an expensive OIII falling out of my hand. It's a wooden tool with the appearance of a spoon. It has a hole in it wich contains part of the barrel of an old eyepiece (only the filter threads)
It's important to use the highest magnification possible in order to recognize the stars near the core of M 15. Especially if one's working with a 'small' telescope like a 10". You'll need also a heavy load of perseverance, but that's something a die-hard observer is born with I guess...
|Object Designation:||Pease 1 (in M 15)|
|Object Type:||Planetary Nebula|
|RA/DEC:||21h29m59s / +12d10m27s|
|Observer:||Fred Hissink, the Netherlands|
|Level of Experience:||25 years|
|Observing Site:||National Park in the eastern part of Holland |
|Date:||10-7-, 10-8- and 10-9-2004|
|Telescope:||10" f/5 dobsonian|
|Eyepieces:||7 mm Nagler-9 mm Nagler 2x Tele Vue barlow, magnifications between 138 and 357.|
Tonight I successfully observed Pease 1 the little planetary nebula associated with the fine globular cluster M15 in Pegasus using my 17.5" f/5 dobsonian. The nebula was found by star hopping through the swarm of stars with the aid of the finder charts at the Pease 1 observations website. The sky is very transparent tonight, but it was my second night of trying to locate the little booger. Last night the seeing just would not support high enough magnifications to positively id the correct field. The most difficult part of the process was finding the right stars to hop from, but tonight I could use mags of 444x (5mm plossl) and 458x (9.7 mm plossl plus 2x barlow) which made it pretty easy to locate the asterisms pointing to Pease 1. 296x (7.5 mm ultrascopic) was used to learn the field then I pushed the magnification up to 444x and blinked using my OIII filter as the cluster moved through the field of view. After about five passes I saw the little p.n. stand out with averted vision aided with the OIII. Next I bumped the magnification up to 458x and saw the nebula with certainty on two out of three passes while blinking with the OIII and using averted vision. And yes this was done with heavy light pollution to my north and a NELM of ~4.5 at zentith. Very, very cool! All total it took ~2hrs of observing time to locate the nebula. I could not have done it with out the help of your fine website.
Charles Rose(from my backyard in Southaven, MS)
Telescope: Celestron 14-inch f/11 Schmidt-Cassegrain, 1980 vintage (orange).
Eyepiece: 8 MM Clave Plossl, yielding 489X. This eyepiece is considerably older than the telescope.
Site: Junk Bond Observatory, located at an elevation of 4400 feet (1340 meters) in the high desert of southeastern Arizona, lat. 31.47 degrees north, long. 110.20 degrees west.
Time: Observation of M15, which took about half an hour, concluded this morning, September 18, at 0753 UT or 12:53 AM local time. M15 at this hour was considerably west of the meridian, but was still at an altitude of 47 degrees. I made the observation after having first slept for several hours, and preserved the resulting dark adaptation by pulling forward the hood of a black sweatshirt so that it blocked ambient light from the sides.
Transparency: As good as it gets. The gegenschein was prominent south of the Great Square of Pegasus, and I was able to trace the full extent of the Zodaical band from Capricornus in the West to the point where it meets the Milky Way in Taurus in the East. Naked eye visibility of M33, difficult for me, is my personal test for autumn sky transparency. Last night the galaxy was easy, and could usually be held in averted vision.
Seeing: Generally excellent. Apart from occasional bursts of turbulence, I would rate the seeing as sub-arcsecond.
The greatest difficulty for me in finding Pease 1 was not the observation itself but matching Doug's finder chart ("Pease 1 Finder Chart 2 of 3") with the view in the eyepiece. Despite the use of 489X, the scale of the actual view of M15 turned out to be much smaller than the scale on the chart. Furthermore, the C14's diagonal flips the view from that presented on the chart, and your observer, lacking the computer skills to print out a flipped chart, was reduced to the old expedient of turning the chart over and illuminating it from below with a dim red flashlight.
Once I matched a "trapezium" of stars on the chart with the same stars in the cluster, it was a relatively simple matter to star-hop to a small group of stars lying to the northeast of the core of the cluster, one of which is actually the planetary. "Blinking" that group by moving a 2-inch OIII filter in and out from between the eyepiece and my eye revealed the planetary. The filter blacked out all nearby stars (and in fact everything but the bright core of M15) but left the planetary undiminished in brightness. This exercise required the use of averted vision.
One perhaps unfortunate moral of this exercise is that successful observation of a "challenge" object is basically a solitary pursuit. On the previous night a group of experienced observers at JBO were unable to see Pease 1 under identically fine sky conditions and using the same equipment and chart. Probably the difference between the two attempts boiled down to levels of dark adaptation and distraction.
A friend of mine is fond of saying, "If it was easy, everybody'd do it." She retired at 35 with a self-made fortune of over a hundred million dollars. When she gives advice, I listen.
On June 22-23, 2001, I was at Fremont Peak, mostly to look at Mars. When I got tired of that I decided to look for GJJC 1 and Pease 1, planetary nebulae associated with M22 and M15 respectively. I seem to have been successful, and with relatively modest aperture, so I thought people might be interested in the details.
CIRCUMSTANCES OF OBSERVATIONS:
Equipment: Astro-Physics 10-inch f/14.6 Maksutov-Cassegrain, with the "small" (23 percent of diameter) central baffle, MaxBright diagonal, 8 mm Brandon and 6 mm Pentax SMC-ED orthoscopic eyepieces (464x and 618x), Orion "Ultrablock" narrow-band filter, used as described below.
Seeing: Looking at Mars made us much aware of seeing during the evening. It was episodic, with intervals a few tens of seconds to a minute long when little Martian surface detail showed, yet there were comparable intervals of much better conditions. During the latter, the diffraction pattern of a suitable star at similar elevation to Mars (and to M22 -- M15 was higher) showed the Airy disc continuously visible but mostly in motion, and the first diffraction ring continuously visible, always in motion, and mostly interrupted; that is, I could not see it as a continuous whole. I observed at 309x (12 mm Brandon) and used the brighter, closer pair of nu Sco for this test; it was well resolved, with much dark space between the two stars. Results with the planetaries were in intervals of good seeing; when seeing got bad, not only the planetaries but also many of the guide stars in the clusters, that I was using, simply disappeared. Except where explicitly stated, the notes that follow are based on moments of good seeing.
Sky conditions: Fremont Peak is not dark like the Sierra Nevada, but transparency was good, and the fog was in on the coastal plain, which much diminished local city lights. These cities have cut back their nighttime lighting considerably -- hurrah for the California power crisis! In any case, sky background brightness was not a factor in these observations, considering the magnifications used.
Aids to navigation: Some time ago, I downloaded the finder charts and images that then existed on Doug Snyder's web site, the home page of which is http://www.blackskies.org. I checked that site while preparing this posting. Doug now has lots more stuff. I have no way to prepare and append graphics to this missive, so I will describe star-hopping and so on with reference to Doug's current images.
With ten inches of aperture, this planetary was harder to find, but much easier to see, than GJJC 1. I started with 464x. Again with reference to Doug's finder images, the boxed "trapezium" of stars on the first image was easy to see with direct vision, as were stars "C" and "D" on the second finder image. Then things got tough, because the background glow of unresolved stars was more obtrusive in M15 than in M22. The effect at the eyepiece was much as in the first finder image.
I made progress by noting that not quite 20" north of the center of M15 is a fairly linear east-west strew of ten or a dozen stars, about 20" long, many as bright as the "trapezium" stars. In Doug's second finder image, the discs of stars in this group range from clearly separated to touching. In the AP-10, hampered by background glow, these stars were difficult to see separately; the effect was rather that of a glowing east-west bar, divided in the middle. The stars were almost as blurred together as in Doug's first finder image.
Going to 618x much improved my ability to see detail in this region, but note that Pease 1 is on the eastern side of a mini-asterism of stars four or five arc-seconds across, all fainter than any in the "bar". Most the stars in this mini-asterism were at or below the limit of direct-vision visibility with the 10-inch, and their half-seen presence lent great confusion to my attempts to view the planetary.
Fortunately, Pease 1 was bright enough to "blink" obviously and immediately with the Ultrablock. I would view the area with averted vision, and see a diffuse glow which (with hindsight) was composed of the merged images of the stars in the asterism -- poorly resolved because I was using a part of my retina not sensitive to detail -- plus the planetary. When I slid the Ultrablock in between my eye and the eyepiece, most of the glow diminished greatly, but a slightly non-stellar patch in the correct position for Pease 1 remained bright. Blinking was immediate, obvious, and entirely repeatable.
I mentioned what I was doing to a couple of people present, but no one was much interested in looking at the planetaries. Most of the local crew aren't as craz- er, enthusiastic, about deep-sky work as I am. Anyhow, it would be difficult to show these targets to a line of people. Each observer would have to spend much time comparing finder images to the eyepiece view, to determine where to look, and would then have to wait for good enough seeing to see the objects.
Without the excellent finder images on Doug's web site, I wouldn't have had a ghost of a chance at finding either Pease 1 or GJJC 1. Furthermore, I cannot overemphasize the importance of good seeing in finding them -- without conditions that made stellar images small enough to see the Airy disc, I am sure that the star-like core of GJJC 1 would have been smeared out and undetectable, even with averted vision, and that the brighter and broader glow of Pease 1 would have merged in with the fuzzy images of nearby stars. I am sure that a lot of credit also goes to the high quality, excellent polish, and freedom from scattering of Astro-Physics's optics -- you can't see the corrector plate on the AP-10 even when you are shining a light on it, the secondary spot just seems to hang there in space.
I hope my remarks are encouraging and helpful to others who may try to view these faint planetary nebulae. It is probably true, that if it were easy, everybody would do it. Yet just because it's not easy doesn't mean it's not possible.
Thanks for your great Planetary Neblae Web Site! It was very interesting for me to find images of all planetary nebulae I had observed this summer. So I could better understand what I have seen. I also found your Ps1 page. Because I am a lucky owner of a 18" Dob, I found Ps1 an interesting target for me. But since I am more often observing with smaller apertures, why not to try it in my 8" f/6 Maksutov-Newtonian.
Of course, I didn't expect much, and I felt no constraint to success, as I went to my first attempt on October 15, 2000. Yes, in a moonlit 3 mag sky, in my backyard, some 50 km north of Vienna, Austria. At 120x I could not resolve much of M15, it was a discouraging view. But I wanted to see what I could do under these conditions, so I went further. At 300x I could resolve more stars, but still couldn't find the trapezium as shown in the finder chart 2 on your web page. I had to use a hood to protect from the bright, moonlit surroundings.
Next I inserted the 5x Powermate into the focuser and pushed the magnification further. At 400x I could locate the trapezium the first time, and now it was easy to locate also the stars C and D and as I followed the line from star A to D I could detect the "finger" of light (as Dave Jurasevich called it in his observing report), protruding out from the dense core of M15.
Now I zoomed in more and more, 600x, 800x and even 1000x. It was possible to resolve the "finger" of light into two clumps of stars, and I had found the location, where to check for Ps1.
At 800x I attached the OIII filter and peered through the eyepiece. At the first moment I could not see anything, after a while the core of M15 emerged as an extremely faint unstructured glow, way too dark. When I reduced the magnification to 600x and 400x, it was still too dark. So I tried the UHC filter at 400x. Mhm, not bad, now I could see some of the brighter stars, to find again the place where to look for Ps1. Now I tried with averted vision, if I could see something there. And, hey, a few times I was able to glimpse a starlike object! I checked again without filter, no there was a clump of stars, but not any brighter star which could have fooled me. I tried again with UHC at 600x, but this was too dim again. So what's up? Did I get it? Maybe, I could go farther than I dared to dream, but I wanted to check again under better conditions.
To get a feeling about the limiting magnitude in my 8" this night I checked the area around M57. At 400x it was not that hard to see a star of 14.6 mag, and eventually at 600x I could even glimpse the 15 mag central star of M57, at all the second successful observation of the 15 mag central star in my 8" (since I first tried it). So I had a feeling how deep I was in at M15, and if I didn't get Ps1, I think I was pretty close.
My next attempt was on October 21, 2000, during an observing session at the Ebenwaldhoehe, a mountain nearly 1000 m high, about 70 km WSW of Vienna. Since I had licked blood, I wanted to tackle Ps1 with my 8" Maksutov-Newtonian. It was a reasonable good night with a limiting magnitude of 6.5 mag. This time my observing partner Walter Koprolin was there, so I had someone to confirm my observation.
As the scope reached near thermal equilibrium and was ready for high power viewing I turned it towards M15 and cranked up the power to 400x. Quickly I had located the trapezium and the "finger" of light. Pushing the power further, to 600x, 800x and 1000x the "finger" was easily resolved into two clumps of stars, as I had it seen during my first "moonlit" attempt. As I inserted the UHC filter I started at 400x. Due to the far better observing conditions now many stars could be seen, too much to isolate the planetary nebula. At 600x I had a good balance, to see enough of the brighter stars for a good orientation. Yeah, and not that hard, where I suspected the tip of the "finger" I could again glimpse a starlike object with averted vision! Eventually the "finger" was visible faintly with averted vision, and yes, the location where I had spotted this starlike object was right!
My observing partner Walter went through all steps again and again and
agreed (to give you a little insight in his observing skills: he was able
this night to glimpse the M57 central star at 300x in the 8"). We concluded,
in the unfiltered view there was no star visible at the tip of the "finger"
in a brightness range that could have peeked through the nebula filter.
The position was confirmed well, so we have little doubt we got Ps1!
We would encourage other observers to try Ps1 with apertures down to 8", and maybe even a good 7" refractor can do it.
One thing is clear to me: without the aid of the finder charts on your web
page and a feeling what to expect from other observing reports I would never
had a chance to succeed with the 8". So it took me 1.5 hours in my first
attempt, and only 10 minutes in my second attempt.
Of course, next time I will repeat this observation with the 18", it should be quite easy now.
As we aimed the scope towards M15 it was quite late, and M15 had already
transmitted the meridian. We had to buckle a bit, to look through the
eyepiece. At 225x we could easily locate the trapezium stars, and also
easily see the (now wellknown to us) "finger" of light resolved into two
groups of stars. As we increased the power to 480x these groups were
nearly resolvable into individual stars, but only in moments of better
seeing. Walter thought, he could see a little disk where Ps 1 is located,
but this is
very uncertain, since sometimes all stars looked like little disks :-)
So we had to do the filter confirmation. When we inserted the UHC filter, the cluster was not dimmed much, so we boosted the power once again to 575x. This gave a better view, and with averted vision, but not very hard, Ps 1 peeked out as a starlike object. We also tried the OIII filter. At this high power the field was very dim. We had to reduce the power to 307x to get a good view. Now we could still see the "finger" of light, and thus exactly locate the position of Ps 1. We got even a better response to the OIII filter, the surrounding stars were very dim, and Ps 1 stood out sharply, although we had to use averted vision to see it.
Having seen Ps 1 now in the 18", we not only have confirmed our observation with the 8", but we have an idea how hard the observation would be for a first time with an undriven scope of this aperture. If we were not familiar where to look and what to do, we sure had to fight against the small field of view at high powers and having to push the scope a little bit every few seconds. So we think a driven scope is not only a benefit, it is nearly mandatory for a successful observation with scopes as small as 8".
Robert Ferguson Observatory, Kenwood Ca. 95452
Christine Churchill, Mike Dickerson, Victoria Brown ( Amateur Astronomers)
Telescope: Fruth 14" F/6 Newtonian at Ferguson Observatory.
Camera: CB245 cookbook ccd.
6 - 60 second stacked ccd exposures.
11 by 9 arc-minute field of view.
Chart used was about 3.5 by 3.5 arc-minutes
In addition to the image (View by Clicking Here), they successfully observed the PN visually on another evening through a 40". This CCD image is also a very good finding aid for Pease 1. Thanks, Folks!
Object Designation: Pease 1 (in M 15)
Object Type: Planetary Nebula
RA/DEC: 21h29m59s / +12d10m27s
Observer: Dave Jurasevich
Level of Experience: 25+ years
Observing Site: Laguna Mountains, 5600 ft. elev., San Diego County, California
Date/Time: August 6, 2000 08:10 UT to 09:48 UT
Moon Illum.: 42%
Moon Rise/Set: 19:00 UT Aug 5 / 06:42 UT Aug 6
Transparency: 6.6 in Area #6 (Pegasus)
Seeing: <1" (Binary BU 75, WDS 21555+1053; 0.82" Sep at epoch 2000.66)
Air Temperature: 66° F
Relative Humidity: <20%
AZM/ALT of Object: 176°25' / 69° 18' at 01:10 PDT
Telescope: 14" SCT f/11 nominal
Eyepieces: 19mm Panoptic, 12.5mm Tak LE, 10.5mm Pentax XL, 7.5mm Tak LE
Magnifications: 225, 340, 390, 545 respectively
I employed a number of eyepiece and filter combinations to find Pease 1, including a 19mm Panoptic, 12.5mm Takahashi LE, 10.5mm Pentax XL and 7.5mm Takahashi LE with and without both a Lumicon OIII and UHC filter.
One of the more difficult parts of this search was getting oriented with the Pease 1 Location Chart 2 provided on the Blackskies website. Finding the highlighted 4-star trapezium lying about 1.5 arc-minutes NW of the cluster core on that chart took several minutes, mainly due to the different image scale of the chart and my eyepiece view. Having found that grouping of stars I then star-hopped my way to the vicinity of Pease I by the following method. Connecting a line from the northwest star (Star A) of the trapezium to the northeast star (Star B) of the trapezium, continue ENE about six times their separation to a star (Star C) similar in magnitude to the two trapezium stars A and B. From Star C follow a line SSE at a PA of about 200° nearly 3 times the separation of the two trapezium stars A and B to a star (Star D) of similar brightness. Drawing a line from the NW star of the trapezium (Star A) to Star D and continuing in a ESE direction about 1.5 times their separation will bring you to the area of Pease 1, which is between 25" to 30" from the center of M15's core at an estimated position angle of 20°. Using a 12.5mm Takahashi LE eyepiece w/o OIII filter, M15 appeared to have a strongly concentrated central core concentrically placed in a generally round but erose and diffuse outer halo having a nominal diameter approaching 3x that of the brighter central core. In the vicinity of Pease 1 on the NNE side of the cluster there appeared a faint "finger" of light jutting radially outward about 5 arc-seconds from the edge of the diffuse outer halo. A few faint stars were resolved at the base of this finger where it merged with the outer halo, as was a stellar point near the tip of the finger. This "finger" area is where I concentrated my search for the planetary nebula.
I initially tried to locate Pease 1 with the 19mm Panoptic (225x) and blinking with an OIII filter but met with no success. Powering up to a 12.5mm Takahashi LE eyepiece (340x) and blinking with an OIII filter I could, after careful study and several minutes of observing finally detect the planetary. It appeared to lie at the tip of the finger previously described and was noted to be similar in brightness to the unfiltered view except that it changed in form from a stellar point to an extended object presenting itself as a tiny round spot of diffuse light when blinked with the OIII filter. With the OIII filter the balance of the cluster dimmed considerably, leaving only the central core and brighter peripheral stars visible as well as a faint glow from the few stars previously noted at the base of the finger. Clearly however, Pease 1 gained in contrast against its background while the balance of the cluster faded with the OIII filter in place. The most pleasing views were had when blinking with the OIII filter and a 10.5mm Pentax XL eyepiece (390x), the extra magnification bringing the nebula out nicely. Once the exact location of Pease 1 was determined, the nebula could be observed with the OIII filter threaded to the 10.5mm Pentax XL barrel end (no blinking), it being held with averted vision. Finally, the OIII filter was blinked with a 7.5mm Takahashi LE eyepiece (545x) to successfully view the nebula, it being held quite easily using averted vision and marginally using direct vision with this eyepiece/filter combination.
Note: A Lumicon UHC filter was also used with the various eyepieces listed above, however it was found to provide a somewhat less contrasted view of the nebula as compared to the OIII filter.
Pease 1 is one of only four known PNe within globulars and the only one which is a reasonable target. A good finder chart is a necessity, though, as the planetary is located is just 25" from the center of M15! At 380x in my 17.5-inch (using an equatorial platform) and the finder chart at this web site it was not difficult to identify a quartet consisting of two easy pairs of mag 14 stars located 1.5' NW of the center. Getting a feel for the scale in the eyepiece compared to the finder chart, I next identified a 30" string of three or four mag 14.5 stars ~50" NE of the center. Pease 1 is situated midway between this string and the center of the nucleus. At 500x, the precise location was pinned down within a small unresolved clump of stars just at the edge of the nucleus 25" NE of center. The PN was apparently buried with this small clump. Blinking with a UHC filter (which dramatically dimmed the cluster), revealed a definite brightening at the NE edge of this clump. With extended viewing this brightening sharpened to a stellar point several times, particularly with the filter attached! It took less than 30 minutes to identify the field and lock onto the position of Pease 1.
I would like to tell you about my first observation of Pease 1 in M-15. On 09/09/99 at Navaho flats,using my 20" scope I gave Pease 1 a try. My friend Larry Cossette printed out a MegaStar chart for me of the field around M-15 which also showed which quadrant Pease 1 was in. Then I used the finderchart shown in #88 april 1992 issue of the Webb Society Quarterly Journal from an article which Brian Skiff wrote on Pease 1. Anyway these charts worked just fine. The Mega Star chart got me very close to the core in the correct quadrant. Then the finderchart in Skiff's article got me right there. At 254X, Pease 1 appeared stellar, requiring the O-III filter and averted vision. There was good response to the O-III & UHC filters. There was no response to the H-B filter. The PN appeared as a star at the end of an extended blob from the core of M-15 when viewed through the O-III filter. The PN would add a point to the end of the extended blob when viewed through the O-III filter and would go away when the filter was removed, leaving the extended blob blunt ended. The real problem observing this PN is how close it is to the center of M-15, about 30". Anyway, Doug, I was really excited about finding it. Also the seeing was not good on that night. Now that I know where to look and what to look for, I shouldn't have problems finding it in the future. Also I think it took me less than an hour to find it. Kent.
We have challenged others in our club and so far no takers.
My partner had attempted Pease 1 two nights earlier with his 22" Dob. We observed at several magnifications, starting at 353x. We scrutinized the target area, blinking in an OIII filter. I was unable to discern a nebula until arriving at 871x, unfiltered. At this power, a small round nebulous patch appeared. We blinked in a UHC which improved the contrast around the edge of the nebula, although we saw no structure in the interior of the nebula. The better view in my opinion was the unfiltered view. We increased the magnification to 1524x, but the image degraded. We retreated to 653x, and the nebula was still apparent, unfiltered. At lower powers, the nebula remained stellar. This exercise brought out a wide variety of Barlows and a few new Radian eyepieces - it was a community effort!
I observe Pease 1 in September 1997 with a 12" Dob and made a sketch.
So here are some details about the observing and its conditions:
Observer: Daniel Restemeier
Skill: Advanced ( many years )
fst: 6mag1 ( visual limiting magnitude)
Telescope: 12" Dobsonian
Object: Pease 1 in M15
I found P1 using a special Finderchart made by the German Deep Sky magazine
"interstellarum". First I saw only the Globular. Then I used the [OIII]
With out Filter there was only a little and faint "starcloud" at the right position. With Filter the outer Areas of M15 disappears and only the center of M15 and the faint glow of P1 was visible. So I was sure it was P1! Another observer saw P1 too. It was one of my hardest observations I've ever made.
But harder was that: This year at the "Bavarian Star Party" I was able to
observe P1 through my 10" Dob too!! The faintest star I saw with naked eye
in Ursa Minor was 6mag4. I used the same method ( filter blinking ) to catch
the very faint glow of P1 with 350x.
I know of nobody else seeing P1 with 10" !
But another German hardcore observer saw P1 with his 14" scope...
So I was very glad to see it with this aperture!
Thank you Daniel for this report and the fine sketch! - Doug
Planetary Nebula Observer's Home Page
Author: Doug Snyder