The July Moon-dark cycle began auspiciously, with clear skies and willing observers from the outset. The Moon hit Third Quarter on July 1st, and several EAS members hit the road in pursuit of dark skies. Robert A, Loren, and Frank headed for the amphitheater at Eagle’s Rest; as it was a Thursday, I stayed home, encouraged by the weekend forecast. A number of the other EAS Irregulars stayed put as well, rather than take advantage of the short but clear night, saving energy for the longer sessions on the horizon. The planetary nebulae—and the rest of the summer splendors—waited patiently for our arrival.
I. Friday night, we split into two parties: a group at the Oxbow (including Jerry, Dan R, Loren, and Robert); and my caveman self, along with Dan B, Alesha, and Mark W, at Linslaw. (Alan had asked to come along but had backed out at the last minute out of necessity.) There had been a serious accident on the road out to Linslaw that had stopped traffic, so we ended up arriving a little bit later than we’d intended. Once atop the crag, telescopes were quickly assembled and electronic gear fired up for the breezy night ahead. Winter coats were donned fairly early as the post-sunset temperatures plummeted quickly, bottoming out in the low 50s (which, after the daily highs, felt pretty damn cold, even without taking the wind into consideration). And as we usually did when our group was split among multiple sites, we intended to gloat about whatever SQM ratings we got, even though the Oxbow might well have equal or better.
My agenda, as it had been in June (despite being interrupted by a one-animal stampede) was to work further through the Astronomical League’s Planetary Nebula program. The end of the first half of it was in sight—I was about 3/4 finished observing the list with the 12.5″ scope, but had the vast majority yet to observe with the 20″. If this weekend’s (and the next’s) forecasts held up, I could end July with only four or five planetaries left to observe with the 12.5″.
Kicking off my agenda this particular night was perhaps the most famous planetary nebula of all, the first one I ever found, and maybe the easiest to find. As soon as astronomical twilight ended, I went to work.
07/02-03/21
LINSLAW POINT
SUNSET: 8:59 PM
MOON: 24 days (rose at 1:47 AM; 29% illuminated)
SEEING: 7
TRANSPARENCY: 6, 7
SQM: 21.54-21.64 (between Hercules and Draco)
NELM: not checked
WEATHER CONDITIONS: temps to upper 50s; some dew; mild breeze
OTHERS PRESENT: DB, AF, MW
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
11:02
M57 (Lyr): Here at Linslaw for the first of what’ll hopefully be a three-night run. I’m starting off (as planned), with M57; this is the first time I’ve ever taken notes on The Ring. [I’m starting off with it because I’m waiting for my two in Sagittarius to rise, and because this one is going to tick a lot of boxes for me in terms of things that I need to see and take notes on.] It’s an embroidery hoop stretched over with gauzy fabric more than it is a Cheerio, or a donut, or any of the other culinary descriptions. The nebula is basically colorless—it’s that trademark planetary nebula gray color—and is elongated P slightly S-F slightly N, 1.25’ x 1.0’. The rim, the ring, the bright portion, averages about 8” to 10” wide, and is very well defined; the interior is fairly regularly bright, and the annularity, of course, is unmistakable—it’s the most-annular planetary after maybe the Helix (I don’t really think even the Helix comes this close). There’s a 13th-magnitude star 1.25’ due F the center of the nebula (the central star is not visible at this magnification, nor is the IC galaxy that’s NP the nebula; it may be visible at higher powers [we’ll go all the way to 4.8mm]). S of the nebula by 5.67’ is an 11th-magnitude star; SP the nebula by 5’ is the F-most, the NF member, of a perfectly-straight SP-NF chain of stars that has five members and a few that are not entirely a part of it; that star is 11.5-magnitude and it has a 12.5-mag star SP it by 1.5’; that star has SP it by 2.5’ a 10.5-mag star; that star has SP it by 1.67’ a 12th-mag star that has SP it by 1.25’ another of 12th magnitude; from the last star F by 1’ is a 13.5-magnitude star, so the SP end of that line is actually a small triangle. P very very slightly N of the nebula by 5’ (so roughly forming an equilateral triangle with the star at the NF end of that line I just described) is an 11th-mag star that has 1.5’ F very very slightly S of it—so between that star and the nebula—a 12th-mag star; those two stars form the S edge of a triangle with the missing IC galaxy [IC 1296]. The brightest star in the field is N somewhat P the nebula by 12.5’ and is 8.5 magnitude. There’s another star N very very slightly P of the nebula by 1.5’, which is 14.5 magnitude and is barely visible at this moment and magnification. Adding the UHC to the 14mm doesn’t overexpose the middle of the nebula like I thought it would; if anything, the rim of the nebula is now much more prominent than the center, suppressing the middle of the annulus; it’s also made the rim less defined and “fuzzier” than it was. There’s distinct addition to the outer glow now that the filter has been added. I can’t pick out specific points around the rim that are brighter; in averted, maybe the SP is a little more diffuse than the rest? I don’t know that I’ve noticed this before; I also don’t know (to my shame) that I’ve really studied the Ring before with this aperture. In both filtered and unfiltered views, the light across the middle of the nebula has a “milky” texture or feel to it. Switching filters to the O-III: oddly enough, the O-III predictably suppresses the field and blows up the contrast of the nebula, but the view is otherwise much the same as with the UHC, although the SP and generally the P side of the nebula have greater diffuseness than the rest of the rim, as was also seen to a lesser degree in the UHC.
IIn the 7mm Nagler, multiple faint stars appear around the nebula; there’s one to the NvsP that might be 15th magnitude; the one I mentioned to the N very very slightly P looks to be double (or a pair). The galaxy still doesn’t show up, even at this magnification. On the F very very slightly N side of the nebula, just inside the rim, there looks to be a concentric dark striation in the rim which is very small; there’s also a greater sense of the diffuse outer edge at this magnification, especially on the P and SP sides; there’s more diffuseness there. [nice to have an eyepiece the filters thread into nicely] I’m not seeing the central star unfiltered, so not that kind of night. With the UHC… the nebula is SO bright… but the filter here does the same things as in the 14mm, making the gossamer quality of the interior and outer edge more evident, almost like there’s dew on the eyepiece around it (but there isn’t). I’m pretty sure I’ve never seen this much of the halo beyond the rim before. There’s also a little added bit of fringe to the NP that’s noteworthy. There’s no central star or visible color; I know others have seen color before, but not me, and not tonight. With the 4.8mm (rather than putting the O-III in the 7mm)… WOW! That’s extraordinarily good! The fringe is all the way around the nebula here unfiltered. It looks like a Romulan plasma bolt (from “Balance of Terror”.) There’s still no central star visible [maybe Jerry will get it tonight?], and no galaxy, either. The nebula’s interior, across the annulus, is darker here than at low power. (Surprising?) This is my best-ever view of this nebula aside from seeing the central star with Jerry. I may be, at fleeting moments, getting the core of the galaxy very very very faintly with averted vision. Just letting the nebula drift through the field is a killer… what a view!
As I finished my notes on M57, I felt a bit of regret: I had no notes from the first time I’d observed it, or any of the other Messier objects. I had nothing to compare my observations to—to see how far my observing skills had grown over the years—and no record of when I’d first observed it. That moment had most certainly been in the backyard of my childhood/young adult home in the suburbs of Cincinnati, and likely in April or May of 1987, not long after I got my first scope (an SP-C8, one of the first black telescopes in Celestron’s line). But my first impressions were lost to time, never to be relived or recovered.
From the “northern” Ring Nebula to the “Southern Ring Nebula.” I had observed NGC 6563 (and several of the other planetaries on my agenda tonight) before, at the Brothers Star Party, and also last month, when I was rudely interrupted by large, fast animal crashing into the amphitheater gate right behind me. But I now had the opportunity for more accurate, more thorough notes, so I was going to reobserve this one and the others I had first swept up in the central Oregon desert four years prior. The seeing down so low in Sagittarius was mediocre and the transparency pretty poor—the brightest part of the Milky Way seemed to terminate right near Baade’s Window, above the “Teapot Spout” of the constellation—and I had to sit on one of my ankles, as the ground was too low to comfortably peer into the eyepiece and my chair (even at its lowest) was too high. But personal discomfort was a secondary concern; there were nebulae to be observed.
11:53
NGC 6563 (Sgr): From the northern Ring to the Southern Ring, NGC 6563, and I’m hoping to get through it before getting charged by an animal this time. This is of course a bit of a letdown after M57; it’s rounder than M57 but without visible annularity at 14mm. (Seeing is not great down here.) It’s a considerably-obvious, reasonably-bright little nebula. It has some P-F elongation to it, spanning 0.67’ by 0.5’. The nebula is colorless, with no central star, no annularity, and no real bright rim; it does seem to be a little brighter on the P side and a little more diffuse on the F (especially to the F somewhat S), and the whole thing is fairly diffuse around the perimeter. The nebula’s in a fairly rich field, as you’d expect being immediately adjacent to the Galactic Center as seen from here on Earth—lots of really faint stars and unresolved starglow in this field. There are a couple of brighter field stars: due S by 12’ is a 7.5 magnitude star; there is a 6th-magnitude star P very very very slightly N of the nebula by 15’, and from that star S very slightly P by 7.75’ is a 7th-magnitude star. 6’ F very slightly N the nebula is a 10th-magnitude star. More in the nebula’s immediate vicinity: almost due N of it by 0.75’ is a 13th-magnitude star. There’s a 12th-magnitude star P somewhat N by 1.3’, and SF the nebula by 1.5’ is a 12.5-magnitude star. 4.5’ SF is the closer of a pair or double, the two stars of which are separated N-S by 10”; those are both 11.5 magnitude, with the one to the S a very slight bit brighter. With the UHC filter… that’s such a better view than the O-III’s going to provide. The filter certainly brightens it up contrast-wise; now, it has a visibly-brighter central region with the diffuseness around it, and that was not really as obvious in the unfiltered view; there was a lot less distinction between the central region and the diffuse outer layer. It is bright, I’ll give it that, especially in the filter; this is probably a superb object overhead in the Southern Hemisphere. With the O-III, the nebula’s expanded to 0.75’ x 0.67’; there’s a lot more visible outer diffuseness to it. It’s definitely more diffuse in the O-III, so that’s pulled in more of the outer envelope. Switching to the 7mm Nagler now; the 4.8mm won’t help as much down this low here. It’s already tough to get a good focus in the 7mm. In the 7mm, the nebula’s really quite impressive, even down this low! Again, I’m not picking up real annularity here for something called the Southern Ring; it’s just not giving me what I expected: it’s bright, quite diffuse on the outer edge, with a more-substantial inner disk to it than at the lower magnification. Even in averted vision, I’m not picking up the annularity. It is a nice nebula, though. With the UHC in the 7mm (and through the horrendous image boil down here), the nebula almost looks like there’s a very small branching, to the S, of the diffuse part of the nebula. In averted, every so often, I get a sense that there might be some irregularity to the brightness in the center, almost but not quite annularity. The O-III should get it, but it just renders the view too dark. It almost looks like, on the S edge of the inner disk, there’s a stellaring present (?). I’m just not getting a good sense of annularity in any filter/eyepiece combo—it’s too dark with the filters and too low for the seeing… a bad combination, even for a planetary.
The breeze had subsided a bit by this point, but the temperature was still falling. I made a note to jump on an Astronomik O-III filter as soon as I could, to replace the old Lumicons I was still using. I think I’ve made this note a dozen times by now.
Before moving on to the next planetary nebula, I stopped by Jupiter to watch the ingress of Io’s shadow on the limb of the planet. I didn’t always bother with transits, when they distracted me from my regular observing agenda. Tonight, though, this one was a welcome break.
I had also observed the next target before (noted at the previous link and here), but not in as much detail. It required sitting on my chair at its lowest setting and craning my neck sideways; I’m starting to wonder if the reduced neck flexibility on my left side is the result of too many observations like this.
12:21
NGC 6629 (Sgr): This one’s also put me in a bit of a bind because of its altitude; this is NGC 6629 in Sagittarius, a small but obvious planetary nebula that very much with the unfiltered view looks like one of those really small ones that’s got the “miniature Eskimo” style, like IC 3568 or IC 2149, where it’s got a very small bright central region and the layer of diffuse fringe around it. It is colorless; I don’t know that there’s a central star visible due to the brightness of the center, which may or may not be shrouding a star. The nebula is 9” in diameter, and round–if it’s elongated, it’s certainly not enough to notice at this magnification. It is bracketed by bright stars in three directions: 7’ due N of the nebula is the brightest star in the field, which is 8th magnitude; 2’ SF is a 9.5-magnitude star; there’s a 9th-magnitude star 10’ P very slightly S of the nebula. 2.25’ N very slightly P the nebula is an 11.5-magnitude star, and S very slightly P that star by 1.25’ is the more N of a pair (it’s probably an actual double); those are separated by 10” NsP-SsF, and are 12.5 and 13.5 magnitude, with the brighter one to the N. With the UHC filter, there’s a tremendous contrast gain. The nebula is not quite as fuzzy now, but definitely more well defined as a disk. I’m going to skip the O-III in favor of the 7mm, which I think will be more useful. With the 7mm, the nebula definitely has that Baby Eskimo hallmark, the IC 2149/3568 look. NP the nebula, just outside of it, there’s either a threshold star or a tiny faint extension of the outer fuzz in that direction. With the UHC added to the optical train, there’s a little more fringe visible now than before (the filter brought it out rather than suppressing it). (Help, help—I’m being suppressed!) With the 4.8 the disk breaks down at this magnification and the fringe takes over. I don’t think that’s illusory, either; the eyepiece really breaks down the border between the disk and the diffuse outer layer, and really makes the nebulous character stand out. This is a good little nebula; it takes magnification really well.
I had intended to head back up into Cygnus after Sagittarius, but it was getting a bit late now, and given the choice between starting Cygnus or finishing Aquila, I opted for the latter. (Regardless, I didn’t get to finish Aquila.) But the planetaries in Aquila had a shorter “shelf life,” being more southerly; I’d be able to work in Cygnus all the way into late October while still having decent enough sky placement for most of them. So Aquila it was, starting with another object I had first “discovered” at Brothers.
In comparing my notes between Brothers and Linslaw, I was surprised to find the Brothers observations hinting at much greater detail. This was no doubt a transparency issue—the two sites were of similar darkness (although Linslaw had the huge light-pollution dome from Eugene Springfield off to the east; Brothers only had Bend), but Brothers had the benefit of being inland farther, away from the humid ocean air that sometimes made Linslaw’s skies murkier than they would normally be.
12:55
Sh 2-71 (Aql): The first one of three remaining in Aquila, and it’s a real trick; this is Sharpless 2-71, and I had to have a photograph to identify it, because it’s really proving difficult here. The nebula’s a low surface brightness glow around a 13.5-magnitude star; the glow is elongated N-S—that’s the easy part, but the visible extent is only about 0.75’ x 0.3’. This is much an averted vision object. To the P side of the nebula is an arc of three stars, of which the one in the middle, the brightest of the three, is due P the nebula by 2.67’; that star is 11th magnitude and is also the right-angle vertex of a little right triangle of which the N-most star is also the N-most in that arc, and that star is N of the right-angle vertex by 1.5’ and is 12.5 magnitude; the third vertex of the right triangle is due P the right-angle vertex by 0.75’ and is 13th magnitude; the third star in the arc is S somewhat F the right angle vertex by 2.67’ and is 11.5 magnitude. From the right-angle vertex P very very slightly S by 3.5’ is a 9.5-magnitude star; from the 9.5-magnitude star SP by 9’ is the brightest in the field, which is 7th magnitude. F very very slightly N of the nebula by 3’ (from the central star) is a 12th-magnitude star, and due N of the central star by 1.75’ is a 14.5-magnitude star. (The arc of three stars has been a big help finding the nebula, both from the POSS and the field itself.) This is one where I believe the filter is going to be a real necessity, so let’s see what the UHC does with it…. The filter makes it distinctly more obvious, but it’s actually quite difficult at this magnification to get a good idea of the shape and size of the nebula; it’s almost football shaped. The filter has definitely brightened it up; the P and F edges are now better defined than the N and S. The central star is still holding barely visible against the filter. The nebula spans a full 1.25’ x 0.75’ with the filter in, and is extremely diffuse even though the P and F edges are more concentrated. The O-III filter definitely helps brighten it even more! I’ve lost the sense that the P and F are better defined; it’s all very diffuse now and the central star has disappeared. The brightness is irregular throughout (hopefully the 7mm will pull this out more). The inner texture seems almost lumpy. With the 7mm Nagler, there’s not much of a sense of the nebula at all. The central star is obvious but the nebulosity really diminishes at this magnification. Adding the O-III to the 7mm, the filter really wrecks the nebula. “Backing down” to the UHC… now that I know where it is from the 14mm, it’s hard not to notice the nebula in the 7mm, even though the UHC overwhelms it at this magnification. I can still tell it’s there, but there’s no detail visible that I didn’t get before. Odd that the 14mm had the best views, but the field is just too dark in the 7mm. Kind of a disappointment, especially compared to my initial view of it at Brothers.
The wind had picked up audibly, creating a nasty rumble on my audio recordings. With Moonrise imminent, I had time for just one more object—one that proved to be a frustrating way to end the night.
1:28
Vy 2-2 (Aql): Racing the moon here, but this is one of the most difficult ones I’ve done in a while, and I needed multiple photographs to confirm and flickering with the O-III filter to verify that this is Vyssotsky 2-2 in Aquila; it is another absolutely-stellar, completely-indistinguishable-from-a-star planetary nebula, with only the barest non-stellar character to it once I’ve identified which one it is. It looks for all the world to be a 13th-magnitude star. There’s no color at this size and magnification, no identifying features like a central star or a visible disk anything like that, just a tiny stellar point. It’s in an active field: P the nebula by 1.25’ is an 11.5-magnitude star, and S very very slightly P (so forming almost a right triangle with the nebula as the right-angle vertex) by 1’ is a 13th-magnitude star. N of the nebula by 1.67’ is a 13.5-magnitude star; F very slightly S of it by 1.75’ is a 13th-magnitude star, and also F very slightly S of it by 4’ is a 10.5-magnitude star. N slightly F by 12’ is the brightest star in the field, which is 8th magnitude; SP the nebula by 11’ is a 9.5-magnitude star. The O-III filter was what I used to flicker the nebula to identify it, and that’s about as much I think it’s the filter is going to do, so we’re going to skip going to the filters in order to go straight to the 7mm Nagler here. (I should probably go straight to the 4.8mm, but with Moonrise imminent, we’ll skip that step this time.) Granted, the seeing isn’t as good as it was before, but even at this magnification the nebula still looks for all the world just like a 13th-magnitude star. But this being what it is, I’m going to go ahead and try the UHC on the 7mm– see if it makes any difference whatsoever. With the UHC in the 7mm eyepiece, the nebula is still as near as stellar. The magnification doesn’t even have the benefit of making it look fuzzy on the edges; it’s just a stellar, stellar point, one that almost even focuses like a star. I’d planned to skip using the 4.8mm due to imminent Moonrise, but I’m going to do it anyway and see if I can get anything at all out of this nebula—it doesn’t have any features whatsoever to make it identifiable as a planetary other than the fact that flickering with a filter does something. All I can say with the 4.8mm is that this may be the most-stellar planetary of all the ones I’ve done; there’s nothing about this that looks nebulous whatsoever. It still even focuses like a star, even at this magnification. Bah! Fie! A pox upon it!
(Yes, I actually used those words in my audio notes.)
With that—and with the Moon having crested the horizon—it was time to go. In a few hours, we would reconvene at the crag for another round of celestial wonders, but for now it was time for teardown and the long drive home.
II. The next night brought more of the same. I still had a target (NGC 6803) remaining in Aquila, but with Cygnus ascendant at sunset and plenty of objects within, I chose to stay amid the Swan, saving the final Aquila planetary for a future date.
The minuscule critters on the sandstone crag rustled and bustled much of the evening. The warmth of the day disappeared along with the Sun; by the time we were ready to start observing—the end of astronomical twilight—I was already wearing my winter coat, and not just because it afforded me extra pockets for eyepieces and filters (although that was certainly a good reason). The brisk breeze threatened to eat through the multiple layers I had put on to avoid getting chilled on the exposed point.
07/03-04/21
LINSLAW POINT
SUNSET: 8:59 PM
MOON: 25 days (rose at 2:08 AM; 23% illuminated)
SEEING: 8
TRANSPARENCY: 7, 2
SQM: 21.42
NELM: not checked
WEATHER CONDITIONS: temps to low 60s; some dew; some wind; fog rolled in at 1:54 AM and shut down observing suddenly
OTHERS PRESENT: JO, DB, LR, MW
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
11:02
Campbell’s Hydrogen Star; BD+30 3639 (Cyg): It’s still pretty early, with fireworks going on and off in the direction of Florence on a breezy night, and we’re already on Campbell’s Hydrogen Star in Cygnus, which I’ve been following for a little while, having backtracked from Psi Cygni. This is an above-stellar planetary that in moments of poor seeing is pretty hard to tell from a star, but when the seeing steadies it’s definitely non-stellar at 112x. It legendarily has a reddish color (I of course don’t see it that way), but it’s definitely an obvious off-white to me. The nebula is 9.5 magnitude and looks composed of a central star with a very small shell around it, maybe 3-4” diameter. Compared to the field stars, it’s just a tiny bit out of focus. The nebula has N very slightly F it by 3.3’ a 10th-magnitude star which has NF it by 4.5’ a 9.5-mag star. S very very slightly P the nebula by 2.5’ is a 12th-magnitude star. P very slightly N of the nebula by 5.5’ is a 10.5-magnitude star; the two 10th/10.5-magnitude stars and the nebula form a small right triangle with the nebula as the right-angle vertex. The brightest star in the field is F somewhat S of the nebula by 14’ and is 8.5 magnitude and is the F-most vertex of a nearly-equilateral triangle with a 10.5-magnitude star 1’ to the P and a 12.5-magnitude star 1’ to the NP. The nebula also has SP it by 2’ the N end of a knot of faint stars 1’ in diameter. There’s a half dozen stars in that knot, which will likely show up better as the magnification increases. I know that UHC or O-III filters supposedly don’t do anything to improve the view of this planetary and H-Beta is the only one that does, but let’s check anyway, starting with the UHC…there is some response, with the nebula brightest of the three (with the 10th- and 9.5-magnitude stars) in the arc. The nebula is slightly more non-stellar than before, but not to a great degree… would still be easy to miss it without knowing it’s there. The color is still not overly distinctive or notable and certainly not reddish. With the O-III, the nebula loses its nebulous character and is indistinguishable from a field star. Now the star at the NF end of that arc of three is the brightest of the three, even with the filter in. Bumping up to 7mm, this is one of these rare objects where the object is as good at 112x unfiltered as in any view I can generate. (Seeing is actually pretty damn good right now). So with the 7mm, the nebulous characteristic is even more pronounced. The little knot of stars contains six or seven members; the nebula also has a 14th-magnitude star 0.5’ almost due S of it. At this magnification, it seems that the nebula has a visible envelope around a central star. The star is shining right through. (The 14mm definitely provides a more-pleasing view of the nebula, however.) With the UHC, the filter preserves the nebulous character; it’s now the brightest object in the field: a couple arcseconds’ diameter, no more than 3-4”, but definitely a disk. (The O-III didn’t work at 14mm, so I’m not going to use it here.) With the 4.8 Nagler, I’m getting a decent focus; seeing’s not great but there are moments when the nebula flashes out. It’s definitely a disk around a central star, and considerably bright at this magnification. A nice view of it.
I’d had Campbell’s Hydrogen Star on my list for years, if not decades; although it was tiny and unimpressive, I still felt a measure of satisfaction at having seen it. The next few planetaries, however, weren’t anyone’s idea of worthy targets.
11:38
NGC 6881 (Cyg): This is the uninspiring and almost impossible to discern NGC 6881 in Cygnus, and up until this the big joke of the night was (for some reason) Bugs Bunny as Leopold Stokowski, but I think this nebula beats it in terms of sheer jokeness because, even in the excellent seeing that we have at the moment, this is nothing more than what looks like a 14.5-magnitude star; it has to have been discovered spectroscopically, because there’s no way anybody except maybe Barnard would’ve noticed this as anything but just a faint field star. It is the P-most vertex in a little irregular diamond with a 13th-magnitude star SF it by 0.75’ and a 14th-magnitude star NF by 0.67’, and then F it by 2’ is an 11.5-magnitude star. The most noteworthy feature of the field, and the brightest star, is almost due NP the nebula by 4.25’ and that star is 8.5 magnitude; it has F very slightly N of it by 1.3’ a 9th-magnitude star, and it also has a 10.5-magnitude star S of it by 0.5’. Also in the field, 3.5’ S very very very slightly F the nebula, is a 9.5-magnitude star; F somewhat S of the nebula by 6’ is another 9.5-magnitude star. F very slightly N of the nebula by 4’ is another 9.5-magnitude star that is the second from N in a NP-SF arc of four; the other three are considerably fainter; that line or arc is about 3’ long. Every one of those little asterisms is more noteworthy than the nebula itself. It has no presence whatsoever. I had to use the O-III to flicker the nebula to even identify it; it’s really hard to pick out even from the POSS plate, and the UHC did next to nothing on it. With the UHC properly threaded into the eyepiece, that little triangle, the bright one to the NP the nebula, actually at least gives you something to lock on to in the field because there’s nothing to identify otherwise. With the O-III… yeah, the filter kills the two fainter stars in the diamond with the nebula, but leaves the two on the P-F axis of it, the nebula and the star F it. There’s just nothing there; no detail, no nothing, just a “star.” [A bird calls.] That bird call? 10 times more interesting than this nebula. It’s just as uninteresting looking at with the 7mm as it is with the 14mm. At least at this magnification, it looks like there may be a really faint star just N of the nebula by a few arcseconds. There, that just made it twice as interesting as it was. Yeah, there’s definitely a star there. With the O-III in the 7mm, maybe now there’s a little bit of something non-stellar to it, but only just; it’s barely brighter than it was. So let’s try the 4.8mm to see if there’s any point to sticking with this one. The sad thing is I bet this one’s on Sky Atlas 2000 taking up space. OK, with the 4.8mm there’s a little tiny bit of presence to the object, a little more than at 7mm. But if that is more than 2”, I don’t know… yeah, it’s non-stellar, considerably more so than at the 7mm. so let’s go ahead and throw the O-III on the 4.8; I can’t believe I’m even going to do this, but I’ve got to be able to say something about it. Nice field, maybe.
It was the first week of July and I had to put my gloves on.
12:18
NGC 6833 (Cyg): This nebula is NGC 6833, another one of God’s little disappointments: just another really, really stellar planetary (at least at the 14mm level). I had to flicker this with the O-III because it’s very, very stellar, looking for all the world like an 11.5-magnitude star. Seeing is excellent and steady right now despite the wind, so the fact that I can’t make this out beyond “stellar” says all that needs to be said about it. The nebula has no color, no real definable quality to it as a nebula; its only quality is “very, very, very stellar.” It’s in a pretty crowded field. F somewhat S of it by 5’ is a 9th-magnitude star; due SF by 12’ is an 8.5-magnitude star. F slightly N by 2.75’ is a 10.5-magnitude star; there’s another 9th-magnitude star 6’ N very very slightly P. S slightly P by 3.67’ from the nebula is the central star of a little tiny ‘Y’ whose stem star is its F-most; the closest star of that Y to the nebula is 3’ S very slightly P and is 13th magnitude; that’s the end of the northern tine; the southern tine ends from the previous star SP by 0.67’ and is 12.5 magnitude. The star at the center of the Y is 0.5’ S of the first star (the N tine) and is also 13th magnitude; the star at the end of the stem is 1’ F somewhat S the first star and is 13th magnitude. The nebula looks to have a threshold star (maybe as bright as 14.5 magnitude) almost due S of it by about 0.3’. Putting the UHC in here to see what happens; again, I had to use the O-III to flicker for it. We’re not going to get much out of this at this magnification, but I definitely want to try the two filters on this object and see what the response is (I already know what it is with the O-III, but not at length). The UHC brightens it up, but there’s no more detail to be had with that filter, just a contrast boost. [I lost the field putting in the O-III; I guess the question would be “do I really give a shit enough to go back to it?” … got it back now, but still don’t know how I lost it.] It still looks stellar with the filter, but now outshines the star to the F very very slightly N by a fair margin. In the 7mm, [and the seeing’s really sharp, even in the 7mm], the nebula still doesn’t have much/any non-stellar character, but has that aforementioned threshold star to the S. The nebula also has another 14.5-magnitude star P somewhat S of it by twice the distance as the one to the S [so 0.67’]. Adding the O-III, we get a 2” diameter to the nebula, just barely above stellar. There’s no way you’d even think to look twice at this as anything but a star. Using the 4.8 Nagler, though probably only unfiltered… almost even a decent focus at this magnification. Still not convinced I’d still be able to identify this as anything but a star without real concentration.
Jerry had identified Pluto within the confines of the dense Sagittarius Milky Way; he was currently giving observing directions within the field to Dan and Loren.
1:10
NGC 6884 (NGC 6776; Cyg): This is the case of mistaken identity known as NGC 6766 (to Sky Safari) or as it’s better known to the rest of us, NGC 6884. This one is very, very slightly non-stellar at 14mm, and it looks to be about 10th magnitude; it’s reasonably bright, just very, very small. It does have a 12th-magnitude star 1.67’ P slightly N. Due S of the nebula by 11’ is a slightly-wavy line of four stars, with the brightest on the F end; that brightest star is 9.5 magnitude; the line runs almost perfectly P-F and is about 3.75’ long. 18’ NP the nebula is the brightest star in the field, which is 9th magnitude and has a very slightly dimmer 9th-magnitude star P slightly S of it by 4.75’, and then from the nebula P very slightly S by 21’ is an 8.5-magnitude star; P somewhat N of the nebula by 9’ a 9.5-magnitude star. NF the nebula by 1.75’ is a 13th-magnitude star; there’s a 14.5-magnitude star S very very slightly P by 1.67’. I’ve already had to do the flicker test on this object as well—this is kind of like the white trash district of the planetary nebulae; these are just really really disappointing. (This’ll hopefully kind of end the white trash district of the planetaries because I’m a little fed up with them; they aren’t as fun as they were last summer.) I’m going to skip the UHC; the O-III really nails the contrast boost and a little tiny bit of the size, particularly in averted vision. It’s now rather Neptune-sized, 3-4”, but with no more detail. With the 7mm, there’s actual legitimate size to this thing now. I think this is another one of those mini-Eskimo types. So let’s try the UHC first in the 7mm. With the UHC, there’s not a lot more detail than the unfiltered view: the nebula’s considerably brighter now (with greater contrast, rather), but there’s no more detail and it’s still just a bright Neptune-esque tiny disk as opposed to something with an outer envelope or anything. I think I can be pretty sure that that’s what it is: just a disk, without much else to identify it. With the 4.8mm, the seeing’s not as good as it was earlier, but there’s still sizable dimension to the nebula, even if just a couple of arcseconds. There’s a faint star 2’ N very very slightly F which is 15th or 15.5 magnitude.
Having seen Pluto, Dan was attempting to dig out Stephan’s Quintet. Mark had gone to sleep in his truck; his laptop was chiming away, warning of impending meridian flip (which would require a major adjustment to his telescope to keep imaging his current quarry (NGC 6946–appropriately, the “Fireworks Galaxy”). The rest of us debated whether we should wake him up; fortunately, he’d already set an alarm for the occasion.
Loren started to pack up, having actual work in the morning. Jerry noted, rather ominously, that the valley below the crag had filled up with fog, visible even in the darkness. I paid it little attention, having settled my scope on the best target of the evening so far: the fine Cygnus planetary NGC 7026.
1:35
NGC 7026 (Cyg): This nebula is the first of the night that’s “worth” something, NGC 7026, also in Cygnus; I want to get a few of these better ones before I go so I can feel rewarded by something. This one’s plainly apparent to the unfiltered view, with a 9.5-magnitude star just F very very slightly N of the center of it. This nebula is brighter toward the center but not with the really intense brightening that a lot of them have. It doesn’t seem to have a central star. It’s a bit oblong N-S, perhaps 15”x 10”. Very diffuse around the edges and even inward toward the middle. It resides in an active field; in fact, there’s a 4.5-magnitude star S very slightly F it by 13’ and a 7.5-magnitude star N very slightly P it by the same distance. P slightly S of the nebula by 7’ is another 7.5-magnitude star that has a 12th-magnitude star 10” NP it; from the nebula S slightly F by 12’ is another 7.5-magnitude star. The UHC definitely pulls out the center of the nebula, increasing the contrast by a huge amount and bringing out the elongation. With the O-III, the 4.5-magnitude star to the S very slightly F has a reddish cast to it, but this could be a residue of the filter on the bright star. The nebula’s distinctly elongated now—this is a fine object! This filter has also “solidified” the diffuseness of the edges and made it more tangible. With the 7mm unfiltered, the elongation looks to be S very very slightly F-N very very slightly P, and the nebula actually looks at times as if it has a dark lane along the major axis, just a thin black slash down the middle. So let’s get a filter in the 7mm; I’m not going to go with the 4.8mm because I’d like to get to 7027 before the night is out. The O-III’s a little too much, but it still gives that impression that there are two separate halves to this nebula on the P-F, divided by a distinct dark lane.
I noticed, while I was observing, that the sky seemed to be fading in the eyepiece. Once I pulled away from the scope, it was obvious why—the fog had left the valley, surrounding us so quickly and thoroughly that I couldn’t even see my observing comrades. I could hear them through the mist, almost gleeful at the opacity and suddenness of its arrival.
There was nothing to do but tear down, completely engulfed in the cold mist. We may have made record time getting off the crag; the drive back down was surreal in the dense fog, and every mile of the trip home seemed like a gamble. It was a relief pulling in to my driveway after almost thirty miles of grey-out, and I wasn’t even concerned that I didn’t get to finish my notes on NGC 7026.
III. The forecast for Linslaw on the 4th of July was clear; we gathered first at Loren’s for a cookout and some fireworks. The others expressed surprise that I wanted to go up to the crag again, after two previous nights. But with a rare three-day weekend, I needed to make every clear night count, even if it was a holiday. Unable to convince anyone else, I went out alone.
There was no doubt where I would begin. Conditions weren’t as good as the previous night had started out, but they were good enough.
07/04-05/21
LINSLAW POINT
SUNSET: 8:58 PM
MOON: 26 days (rose at 2:32 AM; 12.9% illuminated)
SEEING: 5, 7
TRANSPARENCY: 7, 6
SQM: 21.31-21.42
NELM: not checked
WEATHER CONDITIONS: temps to low 60s, but felt cold by midnight; slight breeze that died off about midnight
OTHERS PRESENT: none
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
11:54
NGC 7026 (redux; Cyg): Following up where I left off last night—I’m here alone, with the UHC in the 7mm because I didn’t get to it last night before the fog hit. Seeing’s not as good as last night, but the nebula has still the obvious elongation and dark lane to it, although the bifurcation is much more difficult tonight. There’s a lot of diffuseness around the edges, especially to the N and S. Transparency is much better than last night, as evidenced by the dark nebulae everywhere, including the brightest star in the field—between that star and the 7.5-magnitude star P slightly S the nebula by 7’ or so—between those stars is a long dark mass of decent opacity that’s bordered on its F edge by a 4.5’ long NP-SF-ish string of 13th and 14th-magnitude stars. So the nebula, those two stars (the 4.5 mag and the 7.5 P slightly S of the nebula), and another 7.5-magnitude star SF the nebula form a parallelogram with the dark nebula in the P edge and the nebula at the NF vertex.
Gradually, the conditions improved, even as the temperature fell. I had freshly-cleaned eyepieces, too; I was always reluctant to do any cleaning on astronomical gear, given the risk of sleeking the glass of eyepieces, lenses, and mirrors, but I also needed every bit of contrast I could get for some of these objects, and I wasn’t going to get it with cruddy optics.
My powertank and/or dew heater were a different story. One or the other of them was finally starting to give up the ghost. The indicator lights on both were lit, but somewhere along the line there was no power getting to the dew strip that kept my eyepiece from fogging over. Linslaw usually didn’t have dew problems in the summer, but I hated taking the chance.
I intended to work down “the back” of Cygnus, the area on the constellation’s northeastern end; numerous planetary nebulae lurked here in this dense section of the Milky Way. The next one on my path was Sharpless 1-89, but a lengthy search yielded absolutely nothing. I knew this one would be tough—it was listed on the interstellarum atlas as a target for scopes larger than 12″—but I expected to eventually triumph over it. No such luck. So it was onward to the next nebula, one of Cygnus’ better planetaries.
12:29
NGC 7027 (Cyg): After a considerable amount of time failing to find Sh 1-89, I’ve gone back to this one near C Cygni. This little guy is considerably bright, very small (15” P-F x 12” N-S), and with the faintest tinge of green? This is another of the IC 3568/Baby Eskimo types, with a central star (?), a denser interior, and a bit of outer diffuseness. The inner region is well defined but the outer edge is a little harder to get a fix on. Every now and then in averted vision it looks like the central star pops out; this is difficult to hold steady—perhaps just a bright point-like center? I’ve seen this one at Giant City but didn’t like my notes from it then. The nebula’s in a not-particularly active field for Cygnus; P very very slightly N of the nebula by 2.25’ is a 12th-magnitude star; due P the nebula by 5.5’ is an 11.5-magnitude star; 5.25’ P somewhat N of the nebula is another 11.5-magnitude star; these three stars form a triangle or a capital ‘Y’ with the nebula as base of the stem. NP the nebula by 11’ is a 9th-magnitude star; P the nebula by 0.5’ is a 14th-mag star. There are several 9th/10th-magnitude stars on the S and SF end of the field. F the nebula by another 5.25’ is a small knot or clump of stars of which the two on the S end are the brightest; the clump is about 1.25’ N slightly P-S slightly F by 0.67’ P-F; the star at the extreme S end of that is 11.5 magnitude and it has a 12.5-magnitude star N slightly F it by 0.3’. (Got a lot to say about the starfield; the nebula is a little trickier to find details for.) Adding the UHC makes the nebula the brightest object in the field. Here, there definitely seems to be an outer halo that wasn’t visible before, with the portion of the nebula I was looking at before the brightest portion of a greater whole; it seems to be 0.3’ across with the extra halo. This expanded halo is definitely more noticeable on the P side; it seems to be visible unfiltered and not even difficult once the UHC is removed. (The nebula has such a high surface brightness I could use the 4.8mm no problem, too.) With the O-III: the diffuse circular halo is definitely real in the O-III; it’s quite bright. In the unfiltered 7mm: oh, yeah! Now not only does the whole disk of the nebula pop out more, with the diffuse glow really strong, but the elongation in the nebula really shows up too—it’s elongated P slightly N-F slightly S; I still don’t know if I’m seeing the central star, but there’s a considerably-brighter central region (especially on the P end). That’s a fine nebula; not quite at the IC 2149/3568 level, but a good one nonetheless. [A little wary of animals tonight after the amphitheater experience.] The 7mm also really pops that 14th-magnitude star P the nebula out. With the O-III, the brightness of the nebula just jumps out of the field. It’s really hard to get detail with the filter; it just seems like too much for the conditions and eyepiece. With the UHC: [getting tired a bit] I’m still seeing the halo in the UHC; it’s a little more mottled than in the O-III, with some possible striations in it to the N slightly F and S slightly P. My impression at this magnifiation and with the UHC is that the halo is oriented in a slightly different direction than the “core,” but it’s hard to gauge for certain. With the 4.8mm Nagler and no filter, the nebula is definitely oblong, and the 14th-mag star jumps out. Even the core has an irregular edge, and the transition from core to halo is irregular. I’m also getting a really good impression that the nebula might be pinched in the middle; in moments it seems like the core is bilobial or peanut-shaped. There’s some projection of the core out the P end of the major axis, the core jutting into the halo a tiny bit. A fine object.
1:06
IC 5117 (Cyg): Considerably easier than I expected, this is IC 5117 in Cygnus. It’s very small but not actually stellar; there’s something odd about it that would attract attention when sweeping through the field, and it’s definitely better in averted vision, but it’s so tiny it’s hard to get a handle on it in the 14mm. The nebula seems to be 13th magnitude. It’s the SP vertex of a tiny right triangle; F very very slightly N of it by 0.3’ is a 10th-magnitude star that’s the right-angle vertex of the triangle; almost due N of the nebula by 0.67’ is a 13th-magnitude star. The triangle formed by the nebula and those two stars comprises the S-most (on the S end of the N-S minor axis) vertex of a diamond; at the other end of the N-S axis, 4.5’ N very slightly F the nebula, is an 11.5-magnitude star; P somewhat N of the nebula by 4’ is a close double (?) that is the P-most vertex of the diamond: the S-most component of that double is the brighter; those are separated by 5” and the primary is 10.5 magnitude and the companion is N slightly F it and is 12th magnitude. From the nebula F somewhat N by 3.75’ is an 11th-magnitude star that has a 12th-magnitude star 0.3’ P very very slightly S. (These all comprise the diamond.) There are a lot of other faintish stars in this crowded field. The brightest in the field is SP the nebula by 17’ and is 9th magnitude and has a 12th-magnitude star S slightly F it by 0.3’. Adding the UHC: nice! The nebula is now the equivalent of (or slightly brighter than) the star F very very slightly N of it in that triangle. I can certainly see it better in direct vision than before, although there isn’t much more detail at this magnification. With the O-III, the nebula’s definitely brighter than the star next to it, and much easier in direct vision. I’m not sure I could identify it with the filter in, as the non-stellar quality disappears. In the 7mm Nagler: focus is a little uncertain, but the nebula still has an out-of-focus quality that often comes with these really tiny ones. Going to go straight to the 4.8mm, skipping the filters: there’s a tiny disk visible in the 4.8mm that didn’t show in the 7mm. The 13th-magnitude star to the N of it in the triangle is double, with a 14th-magnitude companion S slightly F the primary. Seeing has gotten better, so I’m going back to the 7mm. I like this nebula—it’s tiny and substellar but does have some presence that many of the other stellar planetaries don’t. With the UHC in the 7mm, there’s just a hint of a disk—not like in the 4.8mm, but there’s a real sense of dimension here, not like there’s a central star or anything beyond a substellar point or the idea that there’s a disk emerging. Swapping the UHC for the O-III in the 7mm, the nebula takes on additional contrast and is the brightest object in the field. The disk-quality is enhanced here. The seeing is steadier; if there was a central star to be found, it might be possible now, but I don’t see any sign of one.
Less than an hour to go before Moonrise. At the pace I’d been working on these AL planetaries, that would leave me two more objects at best, and probably only one. The evening had flown by; no-one else was present to complain about my choice of music (a combination of L.A. hardcore, international non-English punk, some Japanese and Quebecois metal, and a few odds and ends) or my talking to myself (or, rather, my phone), and even the scurrying critters on the crag kept their silence.
I’d expected this last one to be difficult (a la Sharpless 1-89), and was pleasantly surprised—as it seems I often am with these nebulae—to find it a quality target.
1:40
Hu 1-2 (Cyg): A little more something than many of the others I’ve done during this run, this object is very slightly elongated P-F, maybe 6” x 4”, with no color. This nebula doesn’t come to a star-like point; it’s a little more dimensional. It takes direct vision OK but is definitely stronger in averted, and has 0.25’ just SF it a 14th-magnitude star that’s also a nearly-averted object. It also has 1.25’ N very very slightly P it a 13th-magnitude star; due P it by 2’ is an 11.5-magnitude star that’s almost equal magnitude to the nebula; the P star and the nebula form an almost-right triangle with a star S very slightly F the nebula by 3.5’ and that star is 10.5 magnitude. N slightly F the nebula by 4.5’ is an 11th-magnitude star that has a 12th-magnitude star S slightly P it by 0.75’. N very very slightly F the nebula by 7’ is another 10.5-magnitude star; there’s a 9.5-magnitude star 6.5’ P slightly N of the nebula. The brightest star in the field is F slightly S of the nebula by 20’ and is 8.5 magnitude. S of the nebula by 13’ is what looks like a cluster, like a mini Pleiades with the dipper pouring out to the SP; this is about 2.5’ x 1.25’; the SP-most star is its brightest at 11.5 magnitude; most of the rest are 12th-14th magnitudes. I should also point out that the 8.5-magnitude star is involved in a really interesting narrow zigzag of stars with a few bright stars and a lot of dim ones. The UHC filter really brings the nebula out. It’s definitely non-stellar, a little disk with a diffuse outer edge, and may be a couple arcseconds bigger with the filter. It definitely has a brighter, distinct center to it, but not a lot of other detail is visible. This is one small planetary I can say I would’ve noticed right away if it drifted into the field. With the O-III, the nebula is still brighter, with good filter response. Elongation is still noted, but not much else. WOW—the 7mm really adds character to the nebula: it’s elongated P slightly S-F slightly N, and definitely has a brighter central region with diffuse edges around it. The faint star just to the SF it is really popping out now. The nebula comes to a bright point, but I can’t say for sure it’s a central star. A good little nebula at this magnification. [can’t tell if it’s moonlight coming up] That zigzag of stars is so astoundingly regular it has a lot of character here; it’s really noteworthy, the distance between its stars being very uniform. The zigzag has eight stars (one is really faint); the third from S is the brightest (at 7.5 magnitude), but it’s out of the field with the nebula centered; each of the stars is separated by 1.75-2.0’ from each other. With the O-III: the filter just clobbers the field but the nebula brightens a lot. A lot of the outer halo disappears, but you can really see why they call it the Baby Dumbbell (although the view is very unaesthetic with the filter). With the 4.8mm, the nebula is definitely bi-lobed. Nice! Adding the UHC to the 4.8: there’s no way to mistake this for anything but a planetary with the 4.8/UHC combo. It definitely deserves the time I spent with it!
The Moon was still below the horizon, but only just. It was time to go, though; there were other planetary nebulae in need of being scoped out, but this wasn’t the night for them. It had been a rewarding night. Time, now, to call it done and drive home, with the successes of the session left to speak for themselves.
IV. The next Friday—the next night I could get out, given work—found Robert and I at the amphitheater to start, as conditions there were markedly better on the Clear Sky Chart than at Linslaw. The previous night, several of the Irregulars had been down to the Oxbow, but most had reasons for passing on Friday. I was ready for a long session, though—at least as long as I could manage on so little sleep. The sky and weather conditions certainly made the trip worth it.
07/09-10/21
EAGLE’S REST (Amphitheater)
SUNSET: 8:57 PM
MOON: New
SEEING: 8
TRANSPARENCY: 7
SQM: 21.28
NELM: not checked
WEATHER CONDITIONS: temps to upper 60s; almost no dew; air still—almost perfect!
OTHERS PRESENT: 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
10:53
NGC 6803 (Aql): Here at the amphitheater on a night that could turn out to be exceptional—seeing is really sharp, transparency is solid, and we’re at NGC 6803, which has been difficult to track down, although tonight I’ve gotten it before it was totally dark. Unlike a lot (or most) of the other stellar ones, this one has a quality to it that makes it stand out on second glance; you don’t catch it on first glance, but when trying to isolate which star is the nebula, you can do it without a filter, although I still used the O-III to flicker it. Now that it’s dark and the seeing is as good as it is, there’s surely a quasi-stellar appearance to it. It’s in a really fine Milky Way field with a lot of visible dark nebulae around it. There’s a particularly large, opaque dark nebula to the F somewhat N by 10’, and a larger but less-opaque one SP the nebula that runs from S slightly P to N somewhat P the nebula; the darkest part of this one is at the S end. Unfiltered in the 14mm, the nebula may have a very, very tiny disk, 2” at best. It has a 10.5-magnitude star 1.75’ to the N very very slightly P; there’s a 12.5-magnitude star 1’ S slightly P it. Due F the nebula by 6.5’ is another 10th-magnitude star; from that star F slightly S by 3’ is a 9.5-magnitude star. From the nebula N by 14’ is a 9th-magnitude star that has 1’ P very very slightly S of it a 10th-magnitude star that has an 11.5-magnitude star 2.25’ P very very slightly S of it. The brightest star in the field is 20’ F somewhat S of the nebula and is 8th-magnitude, and is on the S end of a 9’ long cloud of stars with about ten brighter ones overlaid on it, including a pair of 10.5-magnitude stars separated by 0.5’ that lie 1’ SF the 8th-magnitude star and form a triangle with it. There’s also a 9.5-magnitude star P somewhat N of the nebula by 13’. I don’t think the filters will help much at this magnification, but we’ll try anyway. With the UHC, the nebula is brighter but also gains a bit of appreciable non-stellarness, maybe to 3-4” size now. That’s all the detail the filter adds; I can’t tell if this is a Baby Eskimo-type nebula or just a bright central star with a faint disk. With the O-III, the nebula’s the second-brightest object in the field after the 8th-magnitude star; it really jumps out, but there’s still no more detail. So with the 7mm, [can lose yourself in these dark nebulae!], seeing is still superb; this is a great view of the nebula. There might be a central star in there, but even averted vision isn’t really helping much to spot it. With the UHC on the 7mm, the nebula gives an (admittedly not great) impression that its edges are not abrupt or a bright rim; there’s more of a diffuse edge (although this is really pushing it). Even in direct vision, you can tell it’s definitely not a star. With the O-III, I’m getting roughly the same impression, but the nebula’s a LOT brighter now. There’s definitely an idea that that’s a Baby Eskimo-type nebula. Still no lock on the central star, although the filter would suppress it anyway. I definitely get a sense that there’s a fringe-covered disk there, although confirmation is still lacking. Moving up to the 4.8mm in the great seeing: there’s a really threshold level star, maybe two, right next to the nebula, one NP and one almost due P the nebula. It’s definitely a fuzzy nebula now, with no solid bright rim; it’s hard to separate a bright central disk from the rest. A fine little object! I was prepared to be disappointed, but this is definitely one of the better stellar planetaries. Adding the UHC filter: there’s a small bright central region that comes to a brighter quasi-stellar point, but no central star is visible. The fuzziness to it seems stronger on the NF, maybe with a bit of elongation that direction as well. A good view of a tiny planetary!
I noticed, as I was setting up, that there was a 1/8″ pinhole in my mirror coating. While not a catastrophe—a telescope optic can take a surprising amount of dirt, grime, and deterioration—it was yet another reminder that I’d been putting off shipping the mirror out to be recoated. I’d be sure to send it off once summer was over. [Narrator: he didn’t.]
I took a break from the planetaries for a while to take notes on one of Herschel’s open-cluster discoveries, continuing in my quest to observe all of Herschel’s objects. From somewhere up the road came a distant gunshot, a not-so-subtle reminder that not everyone out in the woods at night here was interested in scientific pursuits or the aesthetic appreciation of the universe—some just wanted to get drunk and blow shit up.
11:42
NGC 6561 (Sgr): With the planetaries now done for the moment (just for the moment), we’re now looking at more of the Herschel stuff that hasn’t been covered by either of the other lists; this one is NGC 6561, in Sagittarius, which is a sprawling open cluster. It spans 11’ major axis by 8’ minor axis, and has kind of a brightish ‘X’ of stars overlaid on it, near the center of which is a tiny triangle containing two equal-magnitude stars and a fairly considerably fainter one. The major axis is roughly N-S, and the minor axis is not quite perpendicular to that; the minor axis runs SP-NF. The cluster lucida, which I suspect is probably a foreground star, is at the S end of the major axis and is 8th magnitude. At the N end of the major axis is another small triangle that’s much fainter than the one near the center; its northernmost star is the true N end of that axis, and is 11.5 magnitude (as are the other two stars in that triangle); they’re all three very considerably equal. S very very slightly P that star by 0.67’ is another of 11.5 magnitude, and the third lies 0.67’ P somewhat S of the second one, and the first and last stars in that triangle are separated by 1’—so isosceles but not equilateral. The SP and NF ends of the minor axis are composed of two 9.5-magnitude stars; the one on the NF end is a very slight bit brighter. The triangle in the middle consists of two 8th-magnitude stars, of which the S one is very slightly brighter; those are separated N-S by 0.5’, and P very very slightly N of the S of those two by 0.3’ is a 10th-magnitude star; those three comprise the triangle in the middle. Assuming that those are actual cluster members, the cluster has a huge range of brightnesses; there are 35 stars, perhaps, overlaid across some indeterminate unresolved background glow that I think is actually part of the cluster, rather than brightness in the rich Milky Way here. The cluster’s in an area where it’s hard to say that it’s detached from the MW at all, and at first glance it’s sparse enough to not really stand out, so not particularly detached, but is fairly rich and has a large range of magnitudes.
In transcribing my notes on NGC 6561, I noticed a substantial amount of nebulosity strewn around the region in photographs, including a number of patches I probably should have noticed (and certainly would have attempted with a filter had I known they were there). That’s one of the drawbacks of not looking at photos or reading descriptions of objects before observing them; I prefer getting my first impressions at the eyepiece, so as not to color my notes, but it occasionally—like with NGC 6561—means that I miss interesting features that would be worth pursuing.
Although it was still fairly early, I was getting tired. Waking up at 5 AM for work (despite having had a short shift and having gotten a few hours of napping in) was tough on the observing schedule, and it showed in my notes. (Go figure.) I also had the added complication of Mrs. Caveman being gone for university business all week, meaning that I was the beneficiary of the dogs’ restless nights and their need to investigate the yard while it was dark out.
But there was still time to observe, so it was back to planetary nebulae. Having finished Aquila (finally!) and with only one more object in Cygnus (the troublesome Sharpless 1-89, which needed the increased aperture of the 20″ Obsession), it was on into Lacerta.
12:43
IC 5217 (Lac): It’s still fairly early, but I’m here at the very small IC 5217 in Lacerta; this is another planetary that’s actually very similar to NGC 6803 in that it’s a tiny nebula in a populous starfield, but there’s just something odd about it that identifies it, even at low magnification like I’m using here with the 14mm. Seeing is still really sharp, but there’s something odd about this “star,” that when you’re looking at the field, you think “that’s got to be the one.” It doesn’t come to a nice sharp focus, but obviously has a very, very tiny disk, no more than 2-3”. I used the UHC to flicker and identify the nebula, although it’s reasonably identifiable anyway. There’s no color to it. The nebula’s in a busy field in the Lacerta Milky Way; a wide range of magnitudes are present. The nebula could pass as a 10.5-magnitude star at first glance. 1.75’ S very very slightly P it is a 10th-magnitude star; F very very slightly N of the nebula by 2.75’ is a 10.5-magnitude star with a 12th-mag star F very very slightly N of it by 1.25’; from the 10.5-magnitude star S very very slightly F by 0.25’ is a 13th-magnitude star. From the nebula N slightly F by 3’ is an 11th-magnitude star that has an 11.5-magnitude star 1.5’ F slightly S of it, and from the nebula 6’ due N is a 10.5-magnitude star that’s the second in from F on the N and F side of a long ‘V’ shaped pattern; that branch of the ‘V’ contains four stars and runs NP-SF; the P branch, which runs roughly N, is much more populated; the F branch is 7’ long and the P branch about 9’; the point/hinge star is 10.5 magnitude, and the V points roughly N-ward—certainly the P arc of the V does—to the second-brightest star in the field, which is 7.5 magnitude and lies 14’ N very very slightly P the nebula. From the nebula N slightly F by 20’ is the brightest in the field, which is very slightly reddish and is 6.5 magnitude. With the UHC, the nebula is equal in brightness to the star S very very slightly P it, so roughly 10th magnitude; that’s a big contrast boost, although it still remains only very slightly non-stellar. With the O-III, the nebula just leaps right out. It has a little more bulk than in the UHC, a little more substance to the disk. It’ still too tiny to get details, so onward we go to the 7mm Nagler. With the 7mm unfiltered, it’s a little tiny disk, with maybe a tiny halo around it as well. It still responds very well to the UHC: there’s a little central region with an outer halo, a Baby Eskimo-type again. Still no color or elongation, no central star. The O-III provides the best view of the nebula; the outer fringe seems pretty substantial and significant here.
Robert was ready to head out by this point; even if I wasn’t keen to observe at the amphitheater alone, my tiredness and lack of focus made it a good stopping point. I had finished Aquila and Lacerta, and had only one planetary nebula remaining in Cygnus… one which would require heavier artillery than the 12.5″ scope to observe.
Home beckoned.
V. We returned to Linslaw for the final night of July’s observing run—there was still time left in the Moon-dark phase, but we were about to run into another of our seasonal nemeses… forest fire smoke. Although nowhere near as bad as the previous year, the fire season would nonetheless wipe out the better part of six weeks with regard to astronomy and most other outdoor activity (and that’s not even to mention how many homes and properties were destroyed).
For this particular night, we split our group in two: Mark, Bruce S, and I stayed at the normal “upper” Linslaw site on the crag, while Dan B, Alesha, and some of their friends took the lower site below us in the valley. The lower site was more susceptible to dew and fog, but was shielded from the heavy breezes that sometimes afflicted those on the crag.
I had indeed brought the 20″ Obsession, but had made the mistake of not assembling it at home and adjusting the mirror cell. We had cleaned and tuned up the scope earlier in the spring, but had only used it once since then; in the meantime, the mechanical elements of the mirror cell had sat idle and gotten well out of adjustment. Much more out of adjustment, in fact, than I could properly fix by myself in the field. With much profanity and a lot of impatient tinkering, I managed to get the monster scope ion a semblance of collimation, although I was afraid to even sneeze around it for fear of having the whole mirror assembly completely collapse.
While waiting for the sky conditions to improve, for the big mirror to cool to ambient temperature (or at least a passable approximation of such), and for my quarry to rise into a decent viewing position, I went through a list of objects that were already well placed for observing: Saturn (surprisingly decent in poor seeing), the Corona Borealis Galaxy Cluster (of which some galaxies were visible but very disappointing), and NGC 6802 (always a fine sight in a big scope). I also took a tour of globular clusters, from the showpiece M13 and M5, through M4 and M80 in Scorpius (which afforded me the opportunity to sit down and rest my feet due to their low declinations) and M15, rising low in the east. Even M51, the Whirlpool Galaxy, looked OK given the conditions.
Eventually, it was time to work on the one object I had brought out the Obsession for.
07/10-11/21
LINSLAW POINT
SUNSET: 8:56 PM
MOON: 1 day (set at 9:57 PM; 1.1% illuminated)
SEEING: 4-6
TRANSPARENCY: 7 (predicted 8)
SQM: 21.54
NELM: not checked
WEATHER CONDITIONS: temps to mid 60s; no dew; occasional strong breeze
OTHERS PRESENT: MW, BS (DB and crew went to lower site)
All observations: 20″ f/5 Obsession Dob, 14mm ES 82˚ eyepiece (181x, 0.45˚ TFOV) or 7mm TeleVue Nagler (363x, 0.21˚ TFOV)
12:36
Sh 1-89 (Cyg):After repeated attempts with the 12.5” scope, I’m finally getting enough visually to take notes on Sharpless 1-89, a planetary nebula in Cygnus that’s one of the most difficult Items in the entire Astronomical League Planetary Nebula list. It’s fairly mid-sized, actually, as planetaries go, but very, very tenuously held. I’m using the UHC filter at the moment because the nebula was invisible without it; the nebula’s just a little streak, elongated NP-SF 0.75’ by 0.3’, and there’s a star or knot at the SF end that was visible in the unfiltered view with direct vision, and was the only thing that tipped me off that the nebula was there. I’ve looked for this one several times in the 12.5” and have had no luck with it. I know where to look, I’ve had the exact field; the field is only a few degrees from NGC 7026, which I did a few nights ago, but this nebula has been a real bastard otherwise. There’s no color, and not much in the way of definition either; it’s got that spot or embedded star on the SF end, but otherwise, it’s pretty diffuse and pretty hard to get a read on, at least with the UHC at 14mm in the 20 inch. I’m going to actually swap the filters out here; there is nothing of this nebula visible at all with no filter, except for that knot—averted vision maybe shows a very slight bit; but this was not at all visible in the 12.5” the last several nights I’ve been out to look for it. Let me dig out the O-III filter; I want to see what kind of response we get with it, given that this is a planetary that shows more on the red POSS plate than the blue. With the O-III filter there’s actually very little there, and the UHC is by far the better filter for this; it’s just an extremely very very faint diffuse streak with the O-III. The nebula kind of swells out a little bit after prolonged observation with the O-III, looking a little beefier than it was earlier… especially in averted vision, which really helps with this filter on this object. With the filter out now, I can barely tell that there’s something there, but only because I’ve seen it; I would not notice that if I didn’t know exactly where to look. 12’ NP the nebula is a little ‘x’ of 11.5/12th-magnitude stars; it’s about 1.75’ by 0.75’ and has its faintest star on the NP; it’s not a perfect ‘x’, but it’s a good asterism to use to find this object. NF the nebula by 2.75’ is a pair or double of roughly-equal magnitudes; those are 13th magnitude and are separated NP-SF by 10”. F somewhat N of the nebula by 1.67’ is an 11th-magnitude star, and then 7’ F very slightly S of the nebula is a 10.5-magnitude star which is the brightest in the field. I’m glad I finally wrestled this one out; I figured it would take the 20-inch when I saw it in the Interstellarum atlas, but I was hoping for that not to be the case. [I wonder if it would be visible in the 12.5-inch after seeing it in the 20 inch.] The 7mm Nagler is just overkill; it’s not really helping either. The knot or embedded star (I think it’s got to be an embedded star by the way it responded to the filter, which is to say that it basically disappeared)… even unfiltered in the 7mm there’s almost nothing there. I can’t see anything in the O-III filter; this is just not my night. [Actually thought I had the UHC in, as it had been in the wrong box.] OK, well, we know the O-III is not really helpful. But even with the UHC in the 7mm it’s like there’s just too much magnification or something because the nebula’s very difficult. The knot is still visible though, but the nebula itself, at this magnification, just goes away. A really difficult object, maybe the most elusive on the AL list outside of Abells 35 and 36.
I finished my notes at almost 1 AM, stepping down from the ladder and taking a casual assessment of the sky; a quick check of the SQM yielded average scores of 21.54, which were fine, but not as good as we’d seen at Linslaw on some past summer occasions.
With a half-hour teardown and load-in and an hour drive home, it was probably a good idea to call the evening done. I’d accomplished what I’d come to do, and had all but finished the summer planetaries; only a handful of AL planetaries remained in the autumn and winter skies (plus the two Abells mentioned in the notes, which were both late spring objects). Mark and Bruce were still observing, but it was time for me to start getting the giant Obsession disassembled.
My tool-and-optics-cleaning kit was left open for some reason, and a large earwig was making its way along the inside edge of it. I spent an inordinate amount of time trying to evict the creature and momentarily succeeded—it simply crawled back in. I left the kit open until it was time to stow it in the Flex, giving the kit a quick going-through before closing it up. If the earwig was still in there, it wasn’t my responsibility anymore to account for his poor life choices.
Unusually, I was the first one off the crag, I felt a momentary twinge of guilt at leaving so early, but was tired enough when I got home that I didn’t need to justify it.
VI. Ian McDonald died Wednesday. The co-founder and musical genius behind the original King Crimson, McDonald ranked just below Neil Peart, Mel Collins, and Chris Squire in terms of musical influence on my formative days (ironically, McDonald was Collins’ predecessor in Crimson). I suppose there’s truth in the idea that “you know you’re old when the heroes of your youth start dying in waves,” but that hardly prepares one to see the news as it comes across the computer screen.
Few musicians were McDonald’s equal: he played the flute, saxes, clarinet, keyboards, guitar, bass guitar, vibraphone, marimba, dulcimer, and zither with equal dexterity, and added crucial background vocals to both Crimson’s work and that of both Foreigner (of which he was also a founding member) and his own solo work, as well as his work with Crimson drummer Michael Giles. He also arranged and produced In the Court of the Crimson King, Crimson’s breathtaking debut album, in addition to writing much of the music; this music—a melancholic swan song for a history and a world that could have been—has a hold on me to this day, 37 years after I first experienced it.
The Unfrozen Caveman Astronomer 