When I originally started this blog, I had intended to give each observing session its own entry, in order to give a sense of the individual character that each session has. As free time (and energy) has diminished, updates to the blog became less individual and more grouped together by dark cycle, following in part the artifice of the manmade calendar. This means, of course, that updates have been less frequent; it also means that—given that some updates are 20,000+ words long—more time passes between updates, and therefore the memory palls a bit when trying to recall the events of a certain months-ago period of time.
This may explain why I simply forgot to write, in my last entry, about what was the biggest observing event of the March Moon-dark run: the Messier Marathon, this year occurring a couple of weekends too soon, on the night of March 12-13. It was the more-successful of my two attempts at this deep-sky challenge (simply due to the fact that the sky conditions were good throughout the night), although it fell rather stupidly short of full success. However, given how tantalizingly-close we were to full marathon-hood, it certainly has the EAS Irregulars stoked to try again in 2022.
The Messier Marathon—for those unfamiliar—is an all-night observing event based upon the astronomical quirk that, for one weekend late in March, all 110 objects in Charles Messier’s famous catalogue of deep-sky splendors can be seen in the course of a single night. This is due to the placement of the Sun in the sky; as our local star resides in the western half of the constellation Pisces, the nearest Messier object (M74, in eastern Pisces) is nearly 30˚ away… giving just enough time after sunset to catch M74 before it also sets. And the last object in the marathon—M30, in Capricornus—rises a mere 45 minutes before the Sun, making it extremely difficult to catch in the morning twilight.
The early days of the Messier Marathon brought some of the most overwrought, hilarious criticism imaginable from those who felt that it reduced observing to a rote scavenger-hunt type of activity. “I certainly hope no-one gets caught up in this Messier Madness,” wrote one finger-wagging critic in Deep Sky magazine. “It’ll cost you more than you know,” scolded another, leading to my invention of the phrase WTF?. In the days since, the Messier Marathon has become something of a fixture of March astronomy events, most of the critics left to huff ineffectively on the sidelines.
I had attempted the Messier Marathon only once before; on that occasion—with Fred Isberner down in the Crab Orchard National Wildlife Refuge, between Carbondale and Marion, IL—we netted 87 objects in five hours, as the first few hours of the evening were cloudy and the last few hours before dawn were also clouded out. That time, during the mid-Marathon lull (between the end of the Virgo/Coma galaxies and the rise of the summer Milky Way objects), Fred and I were startled—to put it mildly—by the noisy, intense battle between two large predators, occurring less than 70 yards away behind a copse of trees.
There were two basic differences between that previous attempt and the current one, aside from the location and the company: the skies here were clear, and the weather was cold. Back at Crab Orchard, we’d had unseasonably-warm weather for staying out all night; in fact, we’d been treated to a spectacular display of fireflies in the hours after sunset while the sky had still been cloud-riddled. Here, there were no fireflies, no clouds… and no warmth.
Jerry was there, of course, and Dan B; Loren was there, too, but wasn’t planning to stay all night and kept to his carbon-star agenda. Jerry had previously done 109 of the 110 Messier objects from a place in southern Arizona; Dan had never tried a marathon before and was eager to give it a go. For my part, I had somewhat forgotten that we had discussed doing a Messier marathon that particular night, and was less prepared than I like to be for an observing all-nighter.
03/12/21 LINSLAW POINT SUNSET: 6:16 PM MOON: New SEEING: 7 TRANSPARENCY: 7 SQM: 21.35 (at 8:30); 21.67 (at 3 AM) NELM: not checked WEATHER CONDITIONS: temps to mid 40s; moderate dew; slight breeze OTHERS PRESENT: JO, DB, LR All observations: 12.5″f/5 Discovery Dob, 24mm Meade 5000 SWA eyepiece (66x, 1.04˚ TFOV)
I didn’t take real notes; there was no opportunity to do so. Things moved too quickly for that. (Astro-sketching guru Jeremy Perez once did a Messier Marathon in which he sketched every object—a stunning accomplishment.) My notes for the night simply recorded the time I spotted each object, and the observer in whose scope I observed it. The latter was important, as I wasn’t set up in a position to get all of the early evening Messiers; we shared views of some of the earliest ones as a way of observing all 110. As sunset faded, I tracked down M74—the most difficult object in Messier’s list, under even normal circumstances—while Jerry picked up M77, allowing us to cover both critical objects the moment the sky darkened enough.
Rather than my usual eyepiece for finding things—the 14mm Explore Scientific Nagler “clone”—I used the 24mm Meade Series 5000 SWA, which was a clone of the 24mm TeleVue Panoptic. (Had I known at the time that these eyepieces were ripoffs of TeleVue’s designs, I’d have bought the real thing.) The 24mm had a distinct field-of-view advantage, and as I wasn’t really going to be examining the Messiers closely, I didn’t need the extra magnification that much. The 24mm was a fine eyepiece, so the views it gave lacked very little in terms of clarity and sharpness anyway.
A number of fanatically-devoted observers perform what’s called the M3, or “Messier Marathon by Memory.” In this version of the marathon, no charts or apps can be used to find the objects; it all has to be done strictly from memory. I can find perhaps a third of the Messiers by memory, most of them winter or summer objects. This allowed me to work out of sequence from the Pennington list, sweeping up those objects I didn’t need extra time to track down as time and the sky dictated. This included the Orion objects, the Auriga clusters, M46 and 47 in Puppis, the Crab Nebula (M1), the Leo Trio, several of the Ursa Major galaxies, and of course the naked-eye clusters, the Pleiades (M45) and the Beehive (M44).
The Virgo Cluster is always the most challenging segment of a Messier Marathon—not just finding the galaxies, but identifying which is which. In this, using a scope like the 12.5” is almost a disadvantage, as it reveals a great many more galaxies beyond merely those Messier discovered, and it’s necessary to ID them properly. I had done this segment of the marathon before, using the Virgo Cluster chart in Sky Atlas 2000.0, but that was the unlaminated edition of the atlas, and I’d had a transparency with the Messier galaxies highlighted and numbered that I used as an overlay. I still have that atlas and the overlay, but I hadn’t thought to bring them this time; I only had the laminated edition, which was somewhat smaller, and I had no table to put it on to use (my table being at home with a partially-completed jigsaw puzzle on it); I was stuck with Sky Safari, which is a fantastic but less-elegant method of planning an observing session. As it was, starting with M84 and M86 at 10:54, I wrapped up the last member of the Virgo/Coma Cluster, M85, at 11:37 PM. (Pennington’s sequence, oddly, puts M85 at 37th in order, continuing the rest of the cluster at 53rd with M61. Given that M84 and M86 are the most-easily found members of the Virgo/Coma Messier group, there’s no good reason not to begin with them when attempting a Messier Marathon without the Sky Atlas 2000.0 chart.)
We worked our way through the list, checking off chunks of it at a time. Jerry had provided copies of the list he used—from Harvard Pennington’s The Year-Round Messier Marathon—which was considerably different from the list I regularly used (from a long-ago internet source I don’t even recall). The two sequences were similar, but had some significant differences; Pennington has the Cygnus/Lyra/Sagitta/Vulpecula objects before those in Ophiuchus, for example; his sequence of the Coma/Virgo galaxies is also, as already noted, quite a bit different. Nonetheless, we plowed on; as distasteful as it was to consider the cosmic splendors as objects to be checked off of a list without any description or study, there was some satisfaction in watching the blanks fill up with times and initials.
From first spotting M74 at 7:30 and ending Coma/Virgo at 11:37, it was a scramble until 1:07, when I picked up M5 in Serpens. At that point, with the Realm of the Galaxies behind us, we waited for the summer Milky Way objects to rise. As I did at Crab Orchard, I spent part of the lull searching fruitlessly for Omega Centauri. I did manage to spot NGC 5128, the Centaurus A radio galaxy, but it was such a weak sighting through the horizon muck and light pollution that I wouldn’t count it as being “seen.”
The summer objects—in Lyra, Cygnus, Vulpecula, Ophiuchus, Serpens, Scorpius, and northern Sagittarius—took a little over two hours to finish, putting us at just after 4:30 AM. Ten objects remained, most of them low in Sagittarius; one was in Pegasus, three in Aquarius, and one—Messier 30—in Capricornus. M30 was always the most difficult in the Messier Marathon, as it rises so soon before the Sun. But with our attempt at the marathon taking place two weeks before the optimal date, even the Aquarius objects were essentially impossible; morning twilight would blot them out before they were in an observable position. As it was, I needed about half an hour for the remaining Sagittarius globulars (M #s 54, 69, 70, 55, and 75) to rise above the horizon muck for a decent view. Rather than wait it out in the cold, I went back into the Caveman-Mobile to do a bit of reading, alarm set to prevent dozing off or losing track of time.
I woke up with dawn smeared across the sky. None of the curses I shouted made it through the van’s walls, fortunately, but there were many of them. Getting out of the van, I realized that even getting the Sagittarius objects was a lost cause: the Milky Way, Sagittarius, Pegasus, and all but a few dozen of the brighter stars in the entirety of the sky were gone, swallowed up in the breaking morning. The 2021 Messier Marathon was over, and falling asleep had left me stuck at an even one hundred objects.
My log sheet from the 2021 Messier Marathon, frozen eternally at 100 objects.
The lightening sky illuminated what we had glimpsed in the darkness: the valley below the crag had filled with fog during the night, leaving us “stranded” on a dry redoubt of clear sky. Across the foggy valley, a few other high spots poked through, looking for all the world like islands on a misty sea. Passages from William Hope Hodgson and C.S. Lewis rolled around in my brain; certainly, we had become dawn treaders after our long night’s endeavor.
Morning. Photo by Jerry Oltion.
The three of us who remained—Jerry, Dan, and myself—briefly compared notes. Jerry had hit 103 objects, Dan 97 (many of which he’d never seen before). That put us at a perfect average of 100.
Having lasted the night, running this most unusual of races, there was nothing else to do but pack up for the sunlit drive home.
Australopithicenes, like humans, are generally non-hibernating animals; activity may slow during the winter months, but it rarely ceases altogether. Even among those of the astronomy persuasion, sufficient stargazing opportunity is enough to drag the weary out into the cold and/or damp to partake of the starry panoply.
The winter of 2020/2021 provided none of those opportunities. After the September wildfires in the Willamette Valley, we had one observing session until March, when the crappy weather of the western Oregon winter finally began to break and the heavens revealed themselves once again. Had I not finished the Herschel 400 and Herschel II programs the previous spring—had the winter of 2020 not been unexpectedly generous in clear nights—I would be stuck until 2022 before I would have an opportunity to close out those two long-running projects.
Now, of course, I had other projects to work on… most notably, the Astronomical League’s Planetary Nebula and Flat Galaxy observing programs. And while the flat galaxies beckoned, it was the planetary nebulae that needed more urgent attention after the constant rains of the previous five months.
I. And so it was that, when the first Clear Sky Chart forecast came through showing a Moonless night free of clouds and having decent transparency, the astronomers of the Willamette nearly fell over ourselves getting out of town. We convened at Linslaw Point; Mark was set up already, prepping his imaging gear; Jerry and Dan R had the 20″ TriDob, Loren his 18″ Obsession, and I brought Bob the faithful Dob, the better to try to finish the planetary nebula observations I needed before repeating them all with the 20″ Obsession. Dan B and Alesha had his refractor/11″ SCT combo, as he’d sent his 16″ Dob mirror off for recoating at Spectrum. As darkness fell, we managed some wilderness socializing; most of us had had numerous get-togethers during the long hiatus, but it had been a long damp spell as far as social observing went. And when the magic hour of astronomical twilight arrived, it was back to “work.”
03/11/21 LINSLAW POINT SUNSET: 6:14 PM MOON: 28 days (set at 4:32 PM; 2% illuminated) SEEING: 7, 5 TRANSPARENCY: 7 SQM: 21.49-21.53 NELM: not checked WEATHER CONDITIONS: temps to lower 50s; no dew; mild breeze, pleasant OTHERS PRESENT: JO, DB, AF, MW, LR, DR
All observations: 12.5″ f/5 Discovery Dob, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV) or 7mm TeleVue Nagler (225x, 0.36˚ TFOV) unless otherwise noted
7:46 IC 418 (Lep): Got a full house here at Linslaw: Loren and Mark and Jerry and Dan and Dan and Alesha; this is the first time this year that I’m observing with the intent to take notes. We’re starting off with a nice look at IC 418 in Lepus, which I’d taken notes on before at Steve Rogers’ house in Murphysboro. It’s fairly small, but nowhere near as tiny as those stellar-sized planetaries; as seen in the 14mm with no filter, this one’s 10” in diameter, quite round, and has a very bright central star relative to the nebula. The central star (not accounting for extinction from the nebula) looks to be about 10th magnitude. The color of the nebula that’s so noticeable in photographs isn’t quite there visually, at least for colorblind me; it’s definitely not the color that you would expect from a planetary: there’s definitely a trace of color, even if it’s not really identifiable, it’s almost brownish or tan. Due F the nebula by 2.5’ is a 12.5-magnitude star, and then S somewhat P that star by 1.5’ is a 13.5-magnitude star. NP the nebula by 3.5’ is another 12.5-magnitude star that has a 13.5-magnitude star NF it by 0.5’, and those two stars look vaguely fuzzy, like there are unresolved stars in the area, but even in averted I’m not really able to pick anything up [There’s a 16.8-magnitude galaxy, PGC 949730, between the two stars—I must have glimpsed it to have made a note of it.]. F slightly N of the nebula by 17’ is a 9.5-magnitude star; there’s a 10th-magnitude star 10’ F somewhat S, and that is the right-angle vertex of a right triangle that consists of those two brighter stars and the nebula. P very very slightly N of the nebula by 10.5’ is a pair angled SP-NF to each other, with the NF one the brighter; those are separated by 0.5’ and are 11th and 12th magnitudes. I don’t know that it’ll be possible to use the 7mm Nagler for much tonight because the seeing isn’t super steady, at least this early; it’s not bad, but down this low it’s probably only 5 1/2 or 6 (which actually isn’t bad especially for Eugene in the winter). Without the UHC filter, there was a sense that the interior of the nebula was irregularly bright and there were areas of darkness within it, as small as it was; now, with the filter added, the interior’s just kind of blown out or “overexposed.” It’s clearly the brightest object in the region, but now the central star really isn’t discernible amid the nebula itself; it’s just very very bright and the quality that it had with the unaided, unfiltered view is kind of overwhelmed: the very delicate spectral look to it is overwhelmed by having the UHC on it, and the color isn’t visible like it was. Let’s just try the O-III just to say that we did it… but I definitely prefer the unfiltered view to the contrast-boosted version the O-III provides. In the 7mm, the nebula is definitely much brighter and more impressive, the central star still very easy. The SF edge of the rim is just a little brighter than the rest of the shell (I did note this in the 14mm as well); there may be a gap in the nebula toward the NF, and I’m definitely getting a sense like there’s a slightly brighter envelope just around the central star between the mottling and the rim, and that the outer rim is slightly broken up or incomplete. The odd color of the nebula is less evident in the 7mm than in the 14mm.
Before my switch from the 14mm to the 7mm, I stopped by Loren’s scope to take a look at Hind’s Crimson Star, one of the deeper-red carbon stars in the heavens. It appeared pale orange to me, in part because it wasn’t at brightness minimum, where carbon stars are usually at their most colorful, but also due to my eyes’ poor red sensitivity.
And then, back to planetaries, and the other one I’d taken notes on from Steve Rogers’ house in Murphysboro those (seemingly) many years ago.
8:35 NGC 2022 (Ori): The Collarbone Nebula—not one of my favorite nicknames, but at least it’s understandable, given that the nebula lies in the collarbone region of Orion. A pox upon the insistence on giving all objects popular names! This is the other one I took notes on (with IC 418) at Steve’s house in Murphysboro six or seven years ago, and this is definitely a more impressive look at it than I had then… obviously, given the quality of the skies there. In the 14mm, the nebula appears 0.3’ across. It has a brighter central region that makes up about 3/4 of that diameter, and a fuzzy outer edge at which the brightness drops off pretty considerably. I’m not picking up a central star, although there are suggestions that one should be visible. There’s no color to note, as with IC 418, just the greyness typical of most nebulae. From time to time I get a hint that there’s a stellaring on the S slightly P edge of it, but otherwise the disk itself doesn’t seem to have any irregularity in brightness; for a few moments I thought I saw a dark streak across the middle of it, but that was likely just illusory. NF the nebula by 1.5’ is a 13.5-magnitude star; there’s a 12th-magnitude star the same direction about 1’ from the 13.5-magnitude star, and then almost due N of that star by 1’ is another 12th-magnitude star. 1’ due F that last 12th-magnitude star is a 14th-magnitude star that’s surprisingly uncertain and difficult to hold. SP the nebula by 3’ is another 12th-magnitude star, and there’s another P slightly N of the nebula by 3.5’. The brightest star in the field is 7.5 magnitude and is P somewhat N of the nebula by 12’; it’s the middle star in a N slightly P-S slightly F line of five stars; the second from the S end of that line is a faint double, and the 7.5-magnitude star also has one P very very slightly S of it by about 1’; that faint double is oriented N-S and the two are about 12.5 magnitude, separated by 0.25’. With the UHC… oh, wow! That brightened the nebula a hell of a lot, actually. It definitely seems like there is an extra brightening on the SP. There’s also an impression here in the UHC that the nebula comes to a brighter point in the center, and I’m not sure I can shake that impression. Swapping in the O-III… the view is similar to that in the UHC, but the nebula’s even brighter. There’s still no central star, beyond a hint that there should be; the central region is another “step” brighter than it was before. With the 7mm Nagler… that’s a great view! At times there seems to be some annularity or a darker center, but I still don’t think it’s real; I did note it in the 14mm, but it didn’t seem certain beyond a fleeting impression. The SF quadrant seems to be a little bit more diffuse than the rest, a little less defined. There also seems to be a little tuft or filament of fainter nebulosity coming off the F side, just a tiny bit to the N; that’s only visible in averted vision. The previous impression of something on the SP quadrant is still there; I’m pretty sure there’s something in the nebulosity at that point—either an embedded star or a stellaring within the nebula itself.
The breeze turned cold, rumbling in the background of my audio notes. Time for gloves to go on, preferably with hand warmers stuffed inside.
During the course of this observation, Loren was observing NGC 1535, the bright Eridanus planetary dubbed “Cleopatra’s Eye,” and our conversation turned to an injury he’d suffered at the site. I won’t delve into details, but will make note of it here for history’s sake; future generations of Willamette Valley observers will speak of it with hushed whispers.
9:17 NGCs 2452, 2453 (Pup): This is a planetary that gets to go on the never-before seen list, NGC 2452 in Puppis, and it’s just south of a fine open cluster [NGC 2453]—how these did not make the Herschel 400 and Herschel II lists, I don’t know. [Possibly because William Herschel didn’t discover them… duh.] The nebula is decent-sized: perhaps 0.3’, and rather faint, but not super-faint; it’s definitely noticeable immediately upon seeing the cluster. These two are in a very nice Milky Way starfield. The center of the nebula is very slightly dimmer than the outer edge, but there’s no notable central star, and there’s certainly no real color to the nebula. (Seeing’s not great down here; we’re pretty low.) Due S of the cluster by 5.75’ is a double star or pair separated by 0.3’, and these are roughly P-F to each other; they’re pretty equal at 11th magnitude. There’s also a 10th-magnitude star 8’ SP the nebula. The brightest star in the field is P slightly N by 13’ and is 9th magnitude. The brightest star in the cluster is 9.5 magnitude and lies 9.5’ N very very slightly F the nebula; it’s the N-most corner of the cluster, and has 1.25’ S slightly F it a 10.5 magnitude star; and then S slightly F that star by 1.25’ is an 11.5-magnitude star. In between those two fainter stars, and following those, is the bulk of the cluster in a triangular 1.25’ splatter. The cluster extends from there to the SF by 2.5’, and is much richer on the S and the SF ends, with a scattering of brighter stars over the top of a very dense rich patch, with a lot of stars beyond resolution. But the nebula is the primary object of interest here, so let’s throw the UHC filter in here and see if anything happens. With the filter the contrast makes it seem much brighter, but there’s still not a lot of detail to be had; there’s no sense that there is a central star or anything. I’ve noticed in doing these nebulas that the smaller ones benefit much more from the added magnification of the 7mm Nagler than they do from the filters; I don’t think the UHC helps or even the O-III helps quite as much as just doubling the magnification with the 7mm eyepiece. So with the 7mm, there is a very faint star just outside the edge of the fringe on the N, just outside of the nebula. The nebula itself seems to display a little bit of irregularity in brightness and in internal shape, internal structure; the center seems very vaguely dimmer than the rim. That star to the N, the threshold star, almost seems nebulous in and of itself; obviously it’s not, but it almost seems that way. Every so often I get a trace of darkness in the nebula’s interior, and there does seem to be some irregularity to the shape of the internal disk. It’s a nice little nebula at this magnification.
It was during the previous observation that I noticed something glowing in the rough patches of ground near where I was set up. It turned out to be a glowworm, possibly from the same species as the one Jeff L had discovered at Eureka Ridge during a previous observing session. I watched the glowworm to make sure it didn’t come my way, where it could get injured accidentally. It eventually wandered the opposite direction, and I went back to observing with my full attention on the sights in the eyepiece.
The next few objects required sitting on the ground, getting lower and lower in the sky. Given the poor transparency down that low, and the presence of the Roseburg light dome, it was difficult finding even naked-eye guide stars, let alone the ghostly shells of dying suns.
10:13 Mi3-6 (Pyx): Sitting on the ground here (as usual), with the small, not overly-impressive, but nonetheless interesting Minkowski 3-6 in Pyxis. It’s quite small, but still, even down this low, it’s still pretty obviously not stellar, maybe 8” across. It has a number of faint stars N and P it, including a pair of which one is due P by 1’, and that is 12.5-magnitude; there’s one of almost equal magnitude, just slightly fainter, P very very slightly N of that star by 0.67’. 22’ F somewhat N of the nebula is a bluish-white 7.5-magnitude star. N very very slightly P the nebula by 14’ is a double: a 9th-magnitude star that has 5” S very slightly P it an 11th-magnitude star. From the nebula S slightly F by 5.5’ is the brighter of another pair; those may have only 7” separation, and consist of an 11th-magnitude star with a 12.5-magnitude star S very very slightly F it. 7’ S slightly P the nebula is another 11th-magnitude star. With the UHC, the nebula brightens considerably and gives even greater evidence of its non-stellarness. It seems like it might be very, very slightly oblong, elongated SP-NF slightly, but it’s very very difficult to tell at this magnification. Oddly enough, in the UHC, I almost get a sense that the central star is visible; it could just be the interior of the nebula, with there being a very, very small faint outer halo or outer rim around that interior.With the O-III, I’m not really getting much of a distinction from the view in the UHC, at least at first glance; it’s still definitely one of the brighter objects in the field now with the increase in contrast. The nebula seems almost smaller in the O-III than in the UHC, as if there was an outer halo to it before that’s gone now, and the sense that it’s an extended object isn’t there anymore either. With the 7mm… that’s the way to look at it! It’s plain as day non-stellar; this is by far the best view of it. Again, it seems like there’s an outer fringe or halo to it that wasn’t certain at lower power. The elongation seems to really be there, NvvsP-SvvsF; it’s 8” x 5”—very slight but definite. Maybe there IS a central star visible… perhaps in averted vision it’s visible, but it may be that the center of the nebula’s just that much brighter now. This is definitely the best view of the nebula.
Spurred on by my success in finding a non-NGC planetary so far south, I pressed my luck further.
10:26 NGC 2818 (Pyx): OK, I’m gonna pat myself on the back for this one, because I did not think I was gonna be able to find it from here at this latitude. This is NGC 2018 in Pyxis, for which the designation works for the cluster and for the planetary; we’ll argue about that one for a while, but the cluster, down this low, is very, very hazy, very faint; the individual stars are considerably faint for the most part; there’s a scattering, especially on the N end, of star-pairs, the majority aligned N-S. But the nebula is visible about 2/3 of the way from N-S in the cluster. The nebula’s elongated almost due P-F and spans 0.5’ x 0.3’. It’s pretty faint and very diffuse down here and might be mistaken for a faint galaxy. 11’ P very very slightly S of the nebula is a star that looks to be about 9th magnitude [it’s actually 9.5], but extinction is a problem here. 3.75’ NP the nebula is an 11th-magnitude star, and again that’s probably kind of a false magnitude. The cluster is very ambiguously-defined and looks to be about 10’ x 6’ P-F; due S of the nebula by 2.75’ is a knot of stars just on the edge of resolution, and there look to be about four or five stars there of 14th and 14.5 magnitude. F very slightly S of the nebula by 2.5’ is a 12th-magnitude star; again, it’s probably a lot brighter. There’s no real hint of a central star to the nebula, and no color in it but gray. Nor is there much in the way of a central brightening to it here at this magnification unfiltered. So we’re going to throw the UHC on it. (I’d still like to have time enough to go for the Eight-Burst, but I’m going to show off this one to show Jerry and Dan when I’m done.) The cluster is going to disappear because it’s relatively very faint, and it’s gonna just leave the nebula. The UHC really brings the nebula out; it’s still not great. The nebula is brighter N-S on the N-S axis than it is on the major axis, and the ends of the major axis are rather indistinct. I’m going to say that it’s more like 0.67’ x 0.3’. It really really looks like a galaxy from this latitude. I want to try the O-III and see what we come up with. In the O-III, the cluster even looks better suddenly. The cluster is kind-of detached, with a huge range of magnitudes and lots of unresolved background glow; there are probably 18 actual members plus the background glow. The nebula’s definitely brightest on the S end of the minor axis, but it’s really hard to tell anything else because the O-III just kills it. With the 7mm… oh, wow. It almost has a rectangular shape to it. That change to the 7mm is a huge gamebreaker here. The nebula’s kind of vaporous on the ends of the major axis, and still no hint of a central star. A great view, considering how far south this is and how mediocre the seeing is. If this passed overhead, these would be a really famous pair of objects!
I had to check my recording app during this set of notes, fearing that I’d forgotten to start recording. Having done so once, I wasn’t taking chances with these more-difficult objects; who knows when the next opportunity to observe them will arise?
I also made sure to tell Jerry and Dan R to take a look at the NGC 2818 pairing; they were fans of the M46/NGC 2438 combo in Puppis, so the opportunity to see another planetary/open cluster pairing was a rare one. They were more than interested, even if it required sitting on the ground to look.
The next target was one that I’d seen decades before, with only my 70mm Pronto, on a memorable trip with not-yet-Mrs. Caveman and her then-landlords from Flagstaff. It would be a good one to end the evening on, too… if I could find it with no visible guide stars.
11:07 NGC 3132 (Vel): This one is the last of what’s been a very productive night, and it’s one I’ll again pat myself on the back for finding—this is NGC 3132 in Vela, the Eight-Burst Nebula, as seen from 44° North latitude, so hey, congratulations to me. I can’t believe I found it down here, basically with no guide stars! It’s an impressively large nebula– still smaller than I anticipated it being, but also very very impressive nonetheless. I’m using the UHC at the moment; I’m almost literally scraping the horizon here to find it; we are about 5° above the horizon, judging from the Telrad. So the nebula does not show a whole lot; it’s fairly bright but there’s not a lot of detail forthcoming. I did find it without the UHC, and the central star is still visible regardless. The nebula is elongated NvsP-SvsF and is much more indistinct on the N end than the S; on the N end, it kind of fades out gradually. It’s about 0.75’ x 0.5’. I’m just astounded that this thing can be seen from up here; I did see it from the Panamint Valley a long time ago (25 years ago!), in the Pronto, but it was tiny then, obviously. It’s very very diffuse on the edges, especially along the major axis. No color is visible… hardly a surprise given how low it is, and the fact that it’s near the meridian but still in the light dome from Roseburg. (I’m taking the filter out to get some notes on the field.) The central star is really bright; I’m sure my estimate will be way off, given the amount of extinction down this low, but it appears to be about 10th magnitude. SF the nebula by 2.3’ is the more N of a pair of 11th-magnitude stars, separated by about 1’ from the second, which looks a little tiny bit brighter and lies about 1’ SvsP the first. PvsN the nebula by 5.75’ is the P of a P-F pair, of which the P is considerably the brighter at magnitude 10.5, with an 11th-magnitude star F by 0.67’. NsF by 10’ is what I would normally say would be a 9th-magnitude star [it’s 9.5]; it’s the P-most of an arc of three that proceed FvsS and then SsF in 4’ increments; due S of the nebula by 16’ is the brightest in the field, which is probably an 8th-magnitude star [it’s 8.5]. In the 7mm Nagler, this is a really fine planetary nebula (even for this far south), with what looks like a lot of gauzy internal texture in the central region, which is not quite 0.5’ around the central star, and then the ends of the shells extend farther from it. I can only imagine what this one is like from about 15° farther south (since my only other sighting was with a 70mm scope). It reminds me a little bit of NGC 1501 in Camelopardalis; it also has a little bit of NGC 1514 (the Crystal Ball) in it. That is a really awesome nebula!
Loren had left, and others were following. Having showed Jerry and Dan the Eight-Burst, and with all of us in agreement that it had been a fantastic night, we packed up, leaving Mark to finish his images underneath a still-starry sky.
II. Our next observing session took place on the other side of New Moon; as expected of March, clouds and clear skies took alternating turns throughout the month. The Clear Sky Charts for the region showed the Oxbow as the site with the best observing conditions, so off we went on the difficult, winding drive down to the southwest. I wasn’t totally focused this particular evening; I had an endoscopy the next morning, to figure out the source of my random choking episodes. I was also annoyed by my phone’s insistence on switching back to Standard Time at random intervals (as we’d just switched to PDT), which meant that I had to keep track of the start times on my observation notes so that they were accurate. And at some point while we were setting up, Dan commented that my winter gear made me look like Yukon Cornelius from the old Rankin/Bass Rudolph the Red-Nosed Reindeer. It was a gag that stuck around all night.
I was working at higher declinations tonight—fortunate, given the uneven southern horizon at the site. Conditions weren’t great, but the stars beckoned.
The Oxbow crew (L-R): Jerry’s 12″ binoscope, Loren and his 18″ Obsession, Dan B and his hybrid 11″ SCT/5″ refractor rig, and yours truly with Bob the Dob. Robert A had not yet arrived. Photo by Jerry Oltion (hence his absence from the photo).
03/16/21 THE OXBOW SUNSET: 7:21 PM MOON: 3 days (set at 10:50 PM; 8% illuminated) SEEING: 6 TRANSPARENCY: 7 SQM: 21.56 NELM: not checked WEATHER CONDITIONS: temps to upper 40s; no dew; breezy
OTHERS PRESENT: JO, DB, LR, RA All observations: 12.5″ f/5 Discovery Dob, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV) or 7mm TeleVue Nagler (225x, 0.36˚ TFOV) unless otherwise noted
9:04 J320 (Ori): Back at the Oxbow. We still have a waxing crescent moon hanging out for another couple of hours in the sky, but we’re looking at some bright little planetaries tonight, so I’m making it work; the very first one of the night, which I’ve been tracking for quite a while, is Jonkheere 320 in Orion, and after several nights’ attempts at getting this one I’ve finally done it. This is quite a small nebula with just a tiny bit of N-S elongation, around what’s either a very bright central region or a central star that’s just overpowering everything (I suspect the latter). That central star looks to be 10.5 magnitude. The nebula spans 7” x 4”; it’s distinctly non-stellar, but between the moonlight and everything else, it’s kind of hard to get a fix on the actual nebulosity. The nebula makes up the NP corner of a pentagon that has kind of a “king’s crown” shape to it; it’s flattened at the top and very wide. The nebula is also the NF vertex of a small flat isosceles triangle, and is on the following end of the long side of that triangle. Due P the nebula by 1.75’ is a 13th-magnitude star; there’s a 12th-magnitude star about 1.5’ SP that star, and those are the stars in the little triangle with the nebula; the nebula and the 12th-magnitude star are separated by about 3’, and then S somewhat F the nebula by 4.75’ is a 9th-magnitude star; and that star and the nebula make up one side of the pentagon. F the nebula by 16’ is an 8th-magnitude star which has another 8th-magnitude star S very slightly P it by 3.75’; the two 8th-magnitude stars make up one side of the crown-pentagon, the nebula and the 9th-magnitude star make up the other, and the point, the top of the crown of the pentagon, is a 10.5-magnitude star F somewhat N of the nebula by 9’. The nebula shows a little more character in the UHC; if that’s the central star, it’s just as bright with the filter, so I don’t think it’s actually the central star, just a tiny bright central region within the nebula. That’s a difficult pickup; there’s no color or anything in terms of detail at this magnification. With the O-III, the nebula is equal in magnitude to the 9th-magnitude star, so the filter boosted the contrast for sure, but it hasn’t improved the view much otherwise; it’s slightly fuzzy but still not super-easy to pick out as a nebula at first glance. Seeing just is not good enough for the magnification of the 7mm Nagler, but once again, the 7mm does more than the filters in the 14mm do. It’s definitely a nebulous object now, and I couldn’t say that with certainty at 112x at first glance. There’s still just a little bit of N-S elongation here even in the poorer seeing; maybe 7” x 5” (so basically the same dimensions as in the 14mm), but there’s definitely a faint central star visible in addition to the brighter central region.
I made a note to start using my 4.8mm Nagler on these smaller planetaries, in addition to the 7mm; the 4.8 would yield 328x with a 15-arcminute field. (True to form, as of this writing, I still haven’t done it.)
Loren’s current agenda is the AL’s list of carbon stars, and he and Dan were busy tracking down FU Monocerotis, which was near minimum and proving to be a difficult find (as it would be, among the rich starfields of Monoceros). This led to a spate of “FU, Mon” jokes throughout the night.
10:02 J900 (Gem): Sticking with our Jonkheeres here; this is J900 in Gemini, and it was a bugger to find, too. It is just above stellar, and without working from a photograph I could not have found it; as it was, it took me quite a while. The nebula is no more than 7” and has a 12.5-magnitude star just outside of it on the SP. There’s no color. As with J320, J900 has either a central star that overwhelms most of the nebulosity or a very bright, very small core; in this case, I think it’s a visible central star. Our seeing appears to have steadied up again, too, so I’m now able to get a much better focus. I’m also higher in the sky than I was here up in Gemini. The nebula is third from P in a long line of 8th- and 9th-magnitude stars that stretches pretty much across the entire field; at the P end is the brightest in the line, which is P the nebula by 14’ and is 8.5 magnitude; there’s a 9th-magnitude star 5’ P very very slightly N of the nebula. F very very slightly N by 9’ is a 9th-magnitude star. Due F the nebula by 15’ is a 9.5-magnitude star that is at the S very slightly F end of a 2’ long line of fainter stars. I fished the O-III out of my pocket first, so we’ll start with it: OK, that’s almost too overpowering for the nebula; it really greatens the contrast, but doesn’t really help distinguish it from the background stars that much; it eliminates the 12.5-magnitude star almost entirely, but doesn’t do much else. It’s distinguishable as a nebula mainly by its lack of focus… although the filter does make the halo around the central star seem brighter, as opposed to the whole outer envelope; the central star/nexus of nebula is much, much brighter. Changing filters, I think the UHC does a better job here because it doesn’t brighten the nebula as much as the O-III, but doesn’t strip away the obvious nebulous character to it; it works as a nice middle ground. It’s distinctly more nebulous here than in the O-III, and the 12.5-magnitude star is still barely visible. This is the best view of it in the 14mm; I might’ve recognized it as a planetary without knowing it was there in the field. With the 7mm: this is absolutely the best view; it really separates the 12.5-magnitude star from the nebula. This is also the best view as far as identifying it as a nebula; it displays much more nebulous character in the 7mm. The seeing is still not great, but the nebula is definitely nebulous here in ways that it wasn’t at 112x: it has actual, tangible size to it now. There’s still no color in it, but it’s unmistakable as a planetary here in the 7mm, even with the UHC added.
Historical tidbit: Robert Jonckheere was a French astronomer (likely of Flemish extraction) who specialized in double stars.
It had started getting legitimately cold on the rough, paved outcropping of the site, and the breeze had turned more distinctly into wind. I bundled up further. Jerry, Robert, and Dan were busy comparing notes on the Orion Nebula, and Loren was still engrossed in the carbon star hunt, so I don’t know if I looked even more like Yukon Cornelius after adding more winter clothing.
10:46 Mi1-7 (Gem): Staying in Gemini with Minkowski 1-7, but this one is much more difficult than the Jonckheeres. Sky Safari lists it as 0.3’ x 0.2’, but I’ll be damned if I see it as anything but an out-of-focus spot; it has little dimension to it beyond an averted-vision 6” spot. I don’t see it elongated, but it has a very distracting 10th-magnitude star 1’ PvsN it and a 14th-magnitude star F it by 0.75’, and those two really confuse the eye. NP by 14’ is a 9th-magnitude star that has a long string of eight 12th-/12.5-magnitude stars that extends almost due F it; it’s not a perfectly straight line; six of the stars are in that line and two are kind of out of line. S of the nebula by about 8’ or 9’ each (SP and SF) is a pair of stars; the pair to the SP is separated by about 0.67’ and the one to the SF by about 1’; then S very very slightly F by about 13’ is a little scalene triangle of stars with its major axis N-S. Let’s try the UHC here and see what happens, because Sky Safari’s measurement is pretty far off while even the photograph doesn’t show anything beyond just a tiny tiny tiny substellar disk. Let’s take a look and see if there’s anything to be had there with the UHC (this is a Minkowski, so it’s not likely to be as poor as some of the other barely-above-stellar planetaries). The UHC definitely boosts the contrast; the nebula’s fuzzy, and the central star/bright core of the nebula is distinctly brighter than it was without the filter, so I’m thinking that’s a core region rather than a central star. No change in color. It’s impressive how much brighter the nebula is with the filter, because this one is really, really tough for a Minkowski; without the filter, I would not have even really thought of that as a nebula. This one might be able to take the 7mm. With the O-III, yeah… that’s the best view so far. The nebula’s definitely at least 6” across, possibly as much as 8”; it does not really want to come to a crisp focus, but with the O-III and averted vision, the central region of the nebula is almost as bright as the 10th-magnitude star 1’ to the P very very slightly N. Even in the O-III, averted vision helps quite a lot; looking straight at the nebula definitely suppresses it. In the 7mm, it has a hint of a trace of a central star, but not much. It’s distinctly a disk in the 7mm; the brighter center or central star, whichever, of the nebula seems skewed towards the SP corner of it, and the little halo around it stretches a little further in the other directions. In blinking it with the UHC, that impression that the center of the nebula’s skewed to the SP is a little stronger; it feels like there’s a central star there, but I’m pretty sure there isn’t one detectable. That’s actually a really nice nebula—the nicest one so far, and it was the least interesting in terms of the 14mm view, so that was a great improvement. (I wish I could use the 4.8 Nagler on these more often, but the seeing breaks down too easily here in the valley.)
Robert decided he’d had enough, with work in the morning and a long hour’s drive back to civilization. (It was amazing how isolated one could feel on the edge of a substantial road.) As he headed out, I realized how cold I had gotten sitting there, picking these tiny nebulae out of the inky March sky. I decided to set off in search of bigger quarry, with the early spring sky now at the meridian: Abell 31 in Cancer, one of the largest of all planetaries as seen from the skies of Earth.
The nebula lies across the southern half of a diamond of bright (8th/9th magnitude) stars, and though I found the diamond, I wasn’t able to glean more than a photon or two of the nebula, no matter what eyepiece-filter combination I used. (And it would need to be a lower-power eyepiece anyway, given the nebula’s huge size [15’!])
After twenty minutes of futile searching, I gave up on Abell 31, turning to one of its less-known Abell brethren, which had been discussed the previous day on the CloudyNights forum. It turned out to be one of the most-difficult observations I’ve ever made:
11:15 Abell 20 (CMi): Inspired by a thread on CloudyNights, I decided to go after this one anyway, despite its difficulty and the fact that it’s not on the Astronomical League Planetary Nebula program list. This is Abell 20 in Canis Minor, and there’s no way I would’ve seen it without knowing exactly where to look; this is just above the level of “an impression.” The nebula’s 1’, maybe 1.25’ in diameter. But it takes real work, even in averted vision. There’s a couple of faint stars to the SP, and maybe a central star (?).Those two faint stars are SP the nebula, one SP the other by about 0.3’, and then P very very slightly S of the nebula by about 3’ is a 10th-magnitude star that has a 12th-magnitude star 2.25’ P somewhat S of it. From the nebula SP by about 20’ is a double star, or pair, of 8.5 and 11th magnitudes, with the brighter S of the fainter by 0.5’, and then following that pair/double for about 7.5’ is a string that kind of resembles Cygnus, with the pair where Albireo would be. That star that looks like it’s the central star for the nebula is probably is 14.5 magnitude at best, maybe 15th; it may not even be directly in the center, and it looks like it has an equally-faint star N of it by about 0.67’. The O-III doesn’t help that much at all, although there is some improvement; I can hold the nebula fairly well for moments, it’s a super ghostly disk… barely, barely there. This one almost needs a hood to see, but in averted vision it is definitely there… but it is really hard to hold steady for any length of time. There’s not really a whole lot to say regarding detail, but it is visible at an eye-watering level. The O-III made it definite, but it’s not pulling out any extra detail. With the UHC, it’s still definitely there, but not quite as strongly as with the O-III. It’s not really visible with direct vision at all, but in averted, it seems like the nebula might be a little stronger on the F edge, as opposed to the P, but not a lot of other detail is visible. Surprisingly, the 7mm gives a dramatically better view than does the 14mm; I didn’t expect this to be the case with a more-extended nebulous object. It’s definitely more visible in averted here than in the 14mm averted. Filters in the 7mm are too much, though, and even the UHC makes the nebula even harder to see. Returning to the 14mm… once again, the nebula’s not very distinct at all. The unfiltered 7mm offered the best view of this ultra-faint planetary.
And with that—and a lingering look at M42—we collectively called it a night.
III. Two weeks later, we were back at Linslaw, catching some of the few dark hours before Moonrise. Although we would spend almost as much time getting to and from Linslaw as we would observing, there was no reason to waste a clear March forecast, or the camaraderie that comes with being humbled by the grandeur of the universe.
I had roughly an hour and fifteen minutes between astronomical dusk and Moonrise; with the Moon being almost full, its effects would be noticed even before it rose. I spent the falling darkness trying to track down NGC 1886, a flat galaxy in Lepus, but it was already past meridian and very low in the sky, showing next to nothing as I waited. So it was onward to planetary nebulae, then, and whatever the sky had in store.
I had, however, forgotten to take a previous target—Minkowski 3-6—off of my Sky Safari list since I had observed it two weeks before. This led to a repeat observation; while there was nothing inherently wrong with taking another set of notes on a planetary with the same scope, it took time that I might’ve used on an object I hadn’t seen (or at least taken notes on) before.
03/30/21 LINSLAW POINT SUNSET: 7:38 PM MOON: 17 days (rose at 10:27 PM; 96% illuminated) SEEING: 7 TRANSPARENCY: 7 SQM: 21.54 NELM: not checked WEATHER CONDITIONS: temps to low 30s; no dew; some substantial breeze;” cold but not unbearable” OTHERS PRESENT: JO, DB, MW, LR
All observations: 12.5″ f/5 Discovery Dob, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV) or 7mm TeleVue Nagler (225x, 0.36˚ TFOV) unless otherwise noted
9:14 Mi3-6 (redux)(Pyx): I’ve already failed to find anything to write about with NGC 1886, a flat galaxy in Lepus (which, to be fair, is well past meridian), but I’m doing better here with Minkowski 3-6, a small not-quite-stellar planetary in Pyxis. We’re sitting on the ground here and the nebula is, while not obvious, at second glance you definitely notice that it’s not stellar in the 14mm with no filter. The seeing’s not horrible down this low; I’d say it’s probably a six, so it’s about as good as I could ask for. This is a reasonably bright nebula; it’s about 10th magnitude, maybe 10.5, and it lies at the F end of a P-F little not-quite-arc of 12th- and 13th-magnitude stars. P the nebula by 1’ is a 12.5-magnitude star, and 0.67’ P very very very slightly N of that star is a 13th-magnitude star. S slightly F the nebula by 5.5’ is an 11th-magnitude star that may be double; it’s hard to tell at this magnification, but I suspect it is—I think the faint companion is S very very slightly F the primary, and there may be another one almost due F the primary, but I’ll get those better when I use the 7mm. N very very slightly P the planetary by 8’ is the more S of a pair that are almost N-S to each other; the N one is slightly brighter, but they’re very very close in magnitude; I’ll say those are 12th- and 12.2 magnitudes, separated by 0.3’. P very very slightly S of the S of the pair by 4.5’ is an 8.5-magnitude star that has a 9.5-magnitude star N very very very slightly P it by 1.5’, and then from the more-N of the close pair (the 12th/12.2 pair) N slightly P by another 5.5’ is an 8th-magnitude star. The brightest star in the field is F very very slightly N of the planetary by 21’ and is 7.5 magnitude. I want to say the nebula is 8” diameter; it looks round, does not look elongated at all, but it is very plainly not a stellar object. With the UHC, it’s definitely got some size to it. It has a very small, bright center which could be a central star, but it also has a little bit of an envelope. It’s very bright now; with the UHC, it’s the equal of the 9.5-magnitude star, and it’s got a nice field to help find it tooWith the O-III in, the field is almost intolerably dark; other than the 7.5-magnitude star, the nebula’s the brightest thing in the field; it definitely gives an appearance of maybe swelling up to about 10”, with the filter pulling in the nebula’s envelope a little bit. With the 7mm… I was right about the star SsF the nebula; it’s a double with another very faint star due F it by about 0.5’. And between the planetary and the close pair to the N very very slightly P, there’s a little almost-isosceles right triangle of 12th- and 13th-magnitude stars, with the right angle vertex closest to the planetary by 2.75’; the right angle vertex is the brightest of the three of them. The planetary definitely has a brighter core, versus a central star that’s outshining the rest of the middle of it, so there is an interior region that’s brighter as opposed to a point source with an envelope around it. With the UHC, at moments, it almost looks as if there are two brighter elements to the middle of the nebula, almost like it’s got a bright edge and the central star peeking through; it’s kind of hard to hold it that steady. With the O-III, the area around the nebula’s so dark it’s hard to get a good view. I’m still getting the sense that there are two different brighter elements in the middle of the nebula, like a central star and something else, but I’ll need a better image because the POSS plate isn’t good enough. With the O-III, there’s definitely an increase in the fringe on the outside edge.
At the very least, it was a more comprehensive set of notes than the previous entry.
As I was taking notes, Loren used a term that had caught my linguist’s ear more than once before: “boughten,” as in an alternate past participle of “buy.” This was a construction I had only ever heard from Mrs. Caveman’s cousin, and was indigenous to North Dakota, as far as I knew; Loren being from North Dakota, this made perfect sense, and added a data point to my informal survey of the word. Jerry chimed in, however, that he knew of people in Wyoming who used that construction as well. I needed to make a more-formal inquiry about it, apparently.
I had time, I thought, for one more object. So it was back to Gemini, for one of the larger planetaries in the sky: Abell 21, the Medusa Nebula. But the Moon was already making its presence felt, and its extra illumination—even while still below the horizon—caused havoc with this huge, faint, tenuous object. So after several minutes of notes, I abandoned the effort. While I wanted to capture my impressions of the Medusa, it needed to be under sympathetic conditions. And these were decidedly not. The next night’s forecast looked promising, so perhaps I would get another chance.
IV. I didn’t actually get that other chance the next night—while the forecast was for average-to-above-average conditions, the reality wasn’t that good. My plans were for the Medusa, the Headphones Nebula (Jones-Emberson 1) in Lynx, and the Owl Nebula, in addition to further attempts at Abells 35 (Hydra) and 36 (Virgo). The latter two had eluded me in the 20” in better conditions than this particular night was offering, so it was time for a change of plans.
When the transparency is poor, high-surface brightness objects should be the order of the day (night), and those planetaries listed above didn’t qualify (with the exception of the Owl, which was pretty high up and is actually pretty bright). Although the night didn’t quite reach “poor” levels, I rated it a 5 for transparency, which was absolutely the barest minimum level at which I would take notes on an object. Not wanting to waste an early spring night, I changed tactics and settled on a few of the small, bright planetaries still in optimal observing position.
Apparently, there was a sense of urgency among the group, as we had another full house up on the point tonight. Jerry and Dan R were there with the 20” TriDob; Mark and Loren had their regular gear, and Dan B and a coworker had Dan’s 11” SCT—Dan’s 16” Dob primary was significantly delayed in getting recoated.
03/31/21 LINSLAW POINT SUNSET: 7:39 PM MOON: 19 days (rose at 11:47 PM; 83% illuminated) SEEING: 6 TRANSPARENCY: 5 SQM: 21.4 (early, probably poorer later) NELM: not checked WEATHER CONDITIONS: temps to mid 50s; insignificant dew; mild breeze; many mosquitoes; felt colder than it was OTHERS PRESENT: JO, DB, Isaac, MW, LR, DR
All observations: 12.5″ f/5 Discovery Dob, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV) or 7mm TeleVue Nagler (225x, 0.36˚ TFOV) unless otherwise noted
9:32 IC 2149 (Aur): It’s been a frustrating start tonight; the sky is pretty cruddy, so I’m not doing the larger Abell (and similar) planetaries as I’d planned, but I am looking at the moment at the very bright, quite small IC 2149 in Auriga. I struggled a bit with this one; for some reason, it took me forever to figure out the field orientation—I flicked the nebula with the UHC and O-III filters a few times to know that I had the nebula identified, but I was at sea trying to identify my cardinal directions. The nebula has a very bright central star or bright inner region; I’m gonna call it 10th-magnitude, although it could even be 9.5; it’s considerably bright. At first glance, it’s not really obvious as a nebula at this magnification; averted vision really brings out the nebulous character to it. It appears to be about 9”, and has no color beyond Planetary Nebula GrayTM. It’s in a very active field, with a number of little triangles and pairs; due S of the nebula by 12’ is a small triangle, the N-most vertex of which is the faintest at about 11.5 magnitude; it has a 10th-magnitude star 0.75’ SP it, and from the 11.5-magnitude star F slightly S by 1.25’ is a 9th-magnitude star; continuing that line from the faint star in the triangle through the 9th-magnitude star and extending it out and a little further S by another 1’ is a faint pair, roughly N-S to each other, separated by about 0.25’, and those are both 14th magnitude. S slightly P the nebula by 8’ is a 9.5-magnitude star; there’s another 9.5-magnitude star N very very slightly F the nebula by 7.5’. The brightest star in the field is due SF the nebula by 18’ and is 7th-magnitude. P very very slightly N of the nebula by 15’ is the F-most vertex of another tiny triangle; that star is 11th magnitude and it has a 9th-magnitude star P very very slightly N of it by 1’, and that star has a 12th-magnitude star N of it and very very slightly F by 0.5’. Adding the UHC really brightens the nebula up; unfortunately, it didn’t make the seeing or transparency any better. But the nebula is now the second-brightest object in the field after the 7th-magnitude star, and is distinctly non-stellar now even at first glance. In fact, I think it’s grown in size… to the point that the stars all seem to have a little bit of gunk around them, but the nebula certainly has more so, and more tangibly so; it may be 0.25’ now, and the inner 8-9” is a brighter central region with the rest a faint fringe around it. With the O-III, the nebula is now almost tied with the 7th-magnitude star as the brightest object in the field; it’s just a little bit fainter than that star. It’s definitely brighter and having greater contrast than in the UHC; it’s still really hard to get a fix on a central point, focus-wise, so I’m not convinced that there’s a central star there; that may just be a brighter inner region. The outer halo is a little bit overwhelmed, I think, by the filter, because it’s now a little harder to see it. With the 7mm Nagler, that is a nice little nebula—in fact, the detail it shows in the 7mm is roughly equivalent to the UHC view in the 14mm. Here, there definitely seems to be a central star buried in there, because it’s coming to a much-finer point at center; I’m skeptical that that’s all nebulosity in the middle. But at this magnification, the inner region is definitely a surrounding of the central star of several arcseconds in size, with an outer envelope pretty plainly visible around it. The brightest vertex of the little triangle to the due S, the F-most vertex, also has N of it by 0.3’ a 13th-magnitude star. Adding the UHC filter to the 7mm requires me to pull the eyepiece out to reach focus. Although it was difficult at first glance in the 14mm, the outer fringe is much more shaggy or “fringey” in the 7mm. The central star is blotted out by the filter and the nebula-induced contrast gain, but there’s a brighter interior region of 8” or so in the center. With the O-III, it’s even harder to focus; the addition of that filter overwhelms the fringe and reduces the nebula down to little more than the brighter interior.
I caught myself singing bits of Prokofiev’s Peter and the Wolf throughout filter and eyepiece changes here—surely that was more of a Böotes thing than an Auriga thing.
We also had a second brilliant pass of the ISS for that night while I was taking notes on IC 2149. Much as I’m generally dismissive of man-made space stuff, there’s nothing quite like watching a Venus-bright object coursing silently across the sky; there’s something decidedly eerie about an object that bright and fast moving with no sound. (Incidentally, I’m giving up noting the presence of satellites during my observations—there are just too damned many of them, and they’re rarely noteworthy anymore.)
Something Loren said prompted a “Carbon Star Wars” joke, which should’ve fallen flat but didn’t.
10:23 IC 3568 (Cam): Although this one is right above the Little Dipper of Ursa Minor, it’s actually in Camelopardalis. This is an easy, obvious planetary; there’s no doubt about this one, even at first glance. It’s similar to IC 2149 in Auriga, the one that I just finished taking notes on, but this one is even more obvious. It’s 12” in diameter, with a bright whitish interior and a fuzzy exterior/outer envelope; there’s either a stellaring or an actual very faint threshold star on the P very very slightly S side of the nebula. Due S of the nebula by 1.75’ is an 11.5-magnitude star; the nebula itself is about 10th magnitude. There’s another 11.5-magnitude star P very very slightly S of the nebula by 4.5’, and the two stars and the nebula form a very narrow isosceles triangle, with the nebula on the N end of the base. F the nebula and slightly N by 7.5’ is a 10th-magnitude star; N very slightly F the nebula by 1.5’ is a 14th-magnitude star, and then SF by 5.25’ is the middle star in a little Sagitta-like asterism; that star is 13.5 magnitude. F slightly N of that star by 2.5’ is a 12.5-magnitude star, and from the middle star (the 13.5-mag) SP by 2’ is the N component of a double star or pair; those are N very very very slightly P-S very very very slightly F to each other, separated by 0.25’, with the N one being slightly brighter, and those are 13.5 and 14th magnitudes. With the UHC in, there’s clearly a central star shrouded in the interior. This seems very common with these smallish planetaries, at least visually—a buried central star with a bright interior region around it– and the UHC does a nice job brightening (or increasing the contrast of) the brighter interior. In averted vision the outer fringe is also a little brighter, and maybe that’s actually what effect the filter is having—it’s brightening the fringe enough that it’s harder to differentiate it from the bright interior. With the O-III, the nebula is clearly the brightest object in the field. It’s a little hard to focus, but boy, does the contrast increase brighten the nebula right up! That’s a really nice little planetary! The outer halo on this one accounts for only a total of about 4” of the 12” total; the interior region is much larger with this one, I think, than with a lot of these smaller planetaries, relative to the visible halo. Swapping in the 7mm Nagler, that is definitely a threshold star on the P edge of the nebula; it looks like it might be just on (or just inside) the edge of the halo. I’m pretty certain here is a central star visible there, barely peeking through the brightness in that in the interior of the nebula, that center region. The star just off the P almost has a nebulous character to it. With the UHC added, there’s a substellar point in the middle that’s reasonably bright; it can’t be the central star, but perhaps just a tiny inner portion of the interior. The fringe is much more visible at this magnification, but it’s also a nightmare to get a good focus on. The view in the O-III is very similar to that in the UHC here in the 7mm, but the seeing has worsened, so the O-III is a little less useful at the moment. The boundary between the brighter interior region and the fringe is a lot less defined than it was in IC 2149; it’s really hard to make the distinction between the two, unlike in IC 2149, where there was a much more obvious cutoff. I do think this is the “better” of the two visually, as far as displaying detail, although both of these so far tonight have been underrated little nebulae.
Usually at Linslaw, Mark sets up his astrophotography gear in the middle of the clearing, Jerry sets up on the edge overlooking the road, Dan, Loren and I park and set up next to the sandstone crag, and anyone else fills in where there’s space. For those of us next to the crag, observing north is difficult, as the crag blocks most of the view (but also most of the significant light dome of Eugene/Springfield). It also, as on this night, makes for a bit of paranoia—there were skritchings and scrabblings on the crag all evening, the sounds of small creatures scampering to and fro as they went about their nocturnal business. While not overly worried about getting attacked by something, I did wonder if at some point I’d wind up with a chipmunk or kangaroo rat falling off and landing in my scope.
With my two high surface brightness nebulae done, the transparency collapsing again, and Moonrise on the way, I decided to damn the conditions and turn to an oft-overlooked gem of the spring sky—one that I rarely give the consideration it deserves:
11:00 M97 (UMa): Last one for the night, I think, as we’re quickly losing our transparency. This is the Owl Nebula, M97, and it’s not as crisp as I’ve seen it before, and the famous eyes are not very distinct at 14mm with no filter; at particular moments they stand out more, especially in averted vision. The eyes are to the NP and SF; I think the NP eye is a little more obvious. The nebula is not as well defined as the little ones I’ve been looking at tonight; it’s much more diffuse-edged. I’m not getting a real sense of the central star at all. (I think the seeing and transparency did just get a little bit better.) The nebula is 3.25’ in diameter. N very very very slightly F the nebula, 3’ from the center, is an 11.5-magnitude star; there’s a 13th-magnitude star almost due S of the nebula by about 3.5’, and that one has a 13.5-magnitude star F it by 2’; the star to the N very very very slightly F also has a star F it by about 2.5’. The nebula also has a 14.5-magnitude star F it by 5.5’. NP the nebula by 12’ is the S-most of a line of three evenly-spaced stars that runs from that star N very very very slightly P, and those three stars are each about 4’ apart; those are all 10.5 magnitude. And then PsS the nebula by 19’ is a bluish-white 7th-magnitude star. F somewhat S of the nebula by 11’ is a V-shaped pattern of five stars with the “hinge star” of the ‘V’ at the F; those stars are in the 10th- to 12th-magnitude range, and each arm of the ‘V’ is 5-6’ long. (We’re losing our transparency fairly quickly; I’d say in at least half the sky we’re down to about a 5.) In the unfiltered view, the nebula’s edges are more diffuse than those of the smaller nebulas, and with the UHC this is even more true; the N and S quadrants, especially, are very diffuse but vaguely brighter; just under 3’ diameter of this is distinctly brighter, and the outer 0.25’ is kind of irregular. The eyes are much more obvious. The striations in the outer edges are kind of more obvious on the NP; I’m not picking up the little tendril bits like I was before. I don’t know why I’ve always resisted looking at this nebula as a showpiece, because it deserves it. Using the O-III, the edges appear even more ragged; I can’t say that the eyes are as strongly-visible as they were in the UHC. Even in averted, I think it’s better in the UHC (although this could be specific to my filter, too.) On the SF, in fleeting moments, there’s a little separation or gap between the outer edge and some of the inner region, like a bit of slightly-detached fringe at that spot. I think here the SF eye is a little better-defined than the one to the NP. With the 7mm, everything’s blown out; the nebula’s fainter, but I seem to be getting traces of the central star every so often. [Moonlight rising now.] The eyes are very difficult at this magnification. There seems to be, on the NP edge of the 3’ brighter portion, a slightly brighter area there 0.25’ long. The 7mm view isn’t the way to go, compared to the 14mm; the extra magnification and sky darkness don’t offset the extra blurriness. With the UHC in the 7mm (I won’t have time, with imminent Moonrise, for both filters), there’s an interesting twist: the eyes almost give an impression of annularity that doesn’t exist; it’s hard to get a fix on them with the filter in. On the rim to the N (maybe I was wrong earlier) there is indeed some extra brightness. This is too much magnification, and the UHC doesn’t help much; there are better views in the 14mm with either filter. With the O-III in the 7mm, the nebula is actually hard to see; the filter destroys the field, and the eyes are much harder to see against the rest of the nebula. Moving the scope helps. With the unfiltered view in the 7mm, every now and then, the eyes seem as if they smear together; this refers to my earlier comment about the annularity; there isn’t a ring, but something like a dark diagonal line across the middle. The internal brightness shadings are very complex in the 7mm with no filter.
Meanwhile, Loren was providing views of NGC 3242—the Ghost of Jupiter Nebula—through his 18” Obsession.
I suspected that it was the Moonrise—although the Moon was still below the horizon—that was contributing to the poor sky conditions, with the extra glare scattered across the visible sky. By the time the Moon broke through the horizon, we were already tearing gear down for another fortnight, anticipating better skies when we returned to the sandstone crag.
The Unfrozen Caveman Astronomer 