Lighting the Way to Winter

The Milky Way as seen from Eureka Ridge, through the trusses of the TriDob. Photo by Rob Brown, taken via cell phone.

The first weekend of October opened the month with promise. The forecasts all looked good—given the way Willamette Valley Octobers usually close, however, there was some urgency in the cooling air. Any clear nights in the last three months of the year had to be viewed as, potentially, the last opportunities of the year.

I. Our first session out happened on the first night of the month, and off to Linslaw we went. The sky was somewhat cirrusy and the forecast called for cold, dewy conditions. But there was no passing on the night, as our chances for the year were likely running out—and this was no time to be spoiled.

Dan pulled in just after me, along with his friend Karen; Mark was already there with his astrophotography rig, and Robert A had his smaller binoscope set up. I had the 20″ Obsession, the biggest scope on the field, with an agenda geared for it: flat galaxies and several tough open clusters.

But the conditions just weren’t quite there. My first few flat galaxies had no real presence; the transparency was pretty cruddy, and the seeing was poor. I noticed the poor seeing while examining Jupiter and Saturn as the sky darkened, and M11, M72, and M15 after twilight had faded. Even in the dark sky, we could notice cirrus clouds drifting through low in the south, and in the light dome off to the east. This meant that it was also probably passing unseen overhead, affecting both seeing and transparency, and the early (11:00) SQM reading of 21.20 reflected this. So there was little point looking for flat galaxies, or any faint galaxies, which left my agenda down to open clusters and the occasional showpiece object.

Having spent some time with M15, I noticed that one of open cluster targets was close by. In need of some productivity, I headed the big Obsession up that way.

MOON: 25 days (set at 5:03 PM; 21% illuminated)
SEEING: 5, 6
SQM: 21.20 (11 PM), 21.33 (12: 15 AM)
NELM: not checked
WEATHER CONDITIONS: temps to low 50s/high 40s; quite dewy; air still; felt chilly at times; occasional cirrus rolled through low in the south and east
All observations: 20″ f/5 Obsession Dob, 14mm ES 82˚ eyepiece (181x, 0.45˚ TFOV) or 7mm TeleVue Nagler (363x, 0.21˚ TFOV) unless otherwise noted

King 9; NGC 7245 (Lac): Up here at Linslaw on a night that’s not really turning out to be as good as we’d hoped, but we’re making the best use of it that we can. What we’ve got here is King 9, an open cluster in Lacerta up near Cepheus and Cygnus. It lies very near a larger cluster that’s elongated NP-SF and is SP King 9 (I observed this other one for the Herschels but don’t remember the number [NGC 7245]).  King 9 is a small, quite faint, quite compact cluster approximately 1.5’ diameter, with its brightest star on the due N, and that star is only 13.5 magnitude and is slightly separated from the rest of the group, which lies to the S and is obviously very, very rich but very, very distant. With that star and the rest of the cluster stars, the cluster is vaguely triangular, with a wider base to the S end. There is a lopsided, roughly X-shaped pattern of stars—like a trapezoid with two extra stars—that lies NP the cluster (I used that asterism as my field identifier); the nearest of the stars in that pattern to King 9 is N somewhat P by 5.5’. There is a 9th-magnitude star S very very slightly F the cluster by 3.25’ and an 8.5-magnitude star N very very slightly F the cluster by 10’. The larger cluster lies about 5.5’ SP King 9.  This is obviously quite a rich little cluster, with a lot of granular unresolved glow, kind of lost in the field (so not well detached); you have to kind of sweep it through. 1.25’ almost due P the cluster is what looks like a small knot of two or three faint stars in the 14th- to 15th-magnitude range. SP the cluster by 1.5’ is a 12th-magnitude star. King 9 is a very interesting, obviously extremely-distant object, and given that I looked for it with the 12.5-inch scope when I was cataloging the other cluster for the Herschel programs, I’m disappointed but not totally surprised that I didn’t see it then. It’s in a very, very  busy field, and that star to the N very very slightly F the cluster is the brightest in the field. In the 7mm, there’s clearly the “brighter” star to the north and a couple of much fainter ones on that S end of the cluster; the remainder of the cluster looks to be just on the verge of resolution. That group/knot to the P is a trio; two very close together (the two P-most); a third star is SF the second one. [NGC 7245] is kind of a fine object too, but King 9 is what we’ve been after, up there in Lacerta.

The dew and general dampness of the night air, combined with the falling temperature, conspired against us even as the sky conditions slightly improved. I spent time with Neptune and its large moon Triton (always a thrill to spot, given its minuscule size and vast distance) before moving on to Uranus, whose retinue of moons was entirely invisible on the night. NGC 772 and its companion galaxy NGC 770 were somewhat unimpressive just above the brightest part of the Eugene skyglow, a far cry from their usual poke-in-the-eye brightness. I also took a long look at M31, its two bright satellite galaxies M32 and M110, and its more-distant satellites NGC 147 and NGC 185. I noted M31’s largest star cloud, NGC 206, which on this night appeared merely as a brightening in the galaxy’s southern end. Robert had already gone; with the others beginning to tear down, I took a last lingering look at NGC 891, its needle-like form diminished by both eastern-sky light pollution and humid, hazy air.

With a decent forecast for the next night and everyone else yielding to the conditions, I began to break down and stow the monster scope and its ancillary gear. Even with only one set of notes to my credit for the night, it had still been a worthwhile trip out to the crag, and a better use of the evening than staying home flipping through channels or searching for meaning on the Internet. I arrived home shortly after midnight, hoping for better skies on the second—perhaps last—night of the early-October run.

II. The next night seemed to promise similar conditions, but only at the temporarily-open Eureka Ridge; Linslaw, The Oxbow, and Eagle’s Rest all seemed less than optimal on the Clear Dark Sky forecast. So in search of the best sky, and knowing the gate was open, we convened at Eureka Ridge for a reunion with the old place.

The crew this evening included Dan B and Robert—their second in a row—as well as Jerry and Rob Brown, “the tensegrity guy” from OSP ’16. It was nice being back at Eureka, although it was apparent early on that the night’s observing conditions would be pretty much the same as the previous night (only slightly less dark, given the expected difference between Eureka and Linslaw, the latter having darker skies ninety-nine times out of a hundred). As with the previous night, I was armed with the 20″ Obsession.

It was a slightly-more boisterous evening, perhaps due to our resignation at the relatively-mediocre sky quality. Rob fit into the EAS Irregulars group well—as we were setting up, I decided to park the huge Obsession squarely in the road, unconcerned with anyone attempting to drive through; anyone doing so was up to no good and probably there poaching wildlife, so the hell with them. Rob commented that “I don’t really know you, but I like your attitude.” And so the banter was constant throughout the evening, in contrast to the last night’s more-studious feel.

Although I stuck to the same agenda as on the previous observing session, I was more prepared to abandon it in the face of the conditions. I stuck to the planets early on and throughout the night, the transparency (which affects the visibility of diffuse or nebulous objects more than it does star clusters or planets, and more than does the seeing) being worse to the eye than the seeing was. After a spell of planetary observing, it was on to what should’ve been some straightforward work on the “Herschel remains,” those 1600 or so discoveries of William Herschel that weren’t a part of the Herschel 400 and the Herschel II (second 400).

MOON: 26 days (set at 5:35 PM; 13% illuminated)
SEEING: 5, 6
SQM: 21.10 (11 PM), 21.24 (12: 15 AM)
NELM: not checked
WEATHER CONDITIONS: temps to low 50s/high 40s; extremely dewy; air still
All observations: 20″ f/5 Obsession Dob, 14mm ES 82˚ eyepiece (181x, 0.45˚ TFOV) or 7mm TeleVue Nagler (363x, 0.21˚ TFOV) unless otherwise noted

NGC 7165 (Aqr):
 This observation is a tip of the hat to William Herschel, because I don’t have the slightest idea how he found this, NGC 7165 in Aquarius; I’m working on Herschel IIIs now because most of my October agenda is still too low in the sky and the conditions are kind of soft again like last night. This galaxy is one of the most difficult Herschel-related objects I’ve seen, and I honestly have no idea how he found it from England—I’m using the 20-inch and this is still difficult. The galaxy is elongated roughly P-F, and it’s bracketed by 2’ each to the SF and the P very slightly N by two stars; the one to the SF is brighter (12th magnitude) than the one to the P very slightly N of the galaxy (12.5 magnitude). The galaxy is about 0.75’ x 0.5’ and reasonably well defined but considerably faint. It has a definite stellar nucleus to it; the core is very, very gradually arrived at, and only very slightly brighter than the halo. The star to the SF has a 15th-magnitude star N very very slightly F it by 1.25’, and the star to the P very very slightly N has 1.5’ N of it a 14.5-magnitude star that has 1.75’ almost due P it another 14.5-magnitude star; those three stars form a little right triangle, with the second vertex as the right-angle vertex. The galaxy is quite diffuse, but the P edge is very, very slightly brighter than the rest of it, just barely… and everything with this galaxy is “just barely.” The brightest star in the field is N very slightly F the galaxy by 12’ and is 9.5 magnitude. 

As with the previous night, the sky just wasn’t conducive to faint galaxies; my second target—something of a miracle find in the murky skies—provided ample evidence that it wasn’t a “galaxy night.”

While putting together my agenda for the early fall, I’d decided (as I often do when using the Obsession) to throw in a couple of ringers, objects that were difficult even in the best-case scenarios (as if the flat galaxies usually weren’t difficult enough). One such was PGC 70994, a polar-ring galaxy in Pisces, which I found in Jimi Lowery and Alvin Huey’s guide to such ring galaxies. This galaxy—at an immense distance of nearly a billion light years!–resembles a tiny ‘X’ in photographs due to the offset of the polar ring to the nucleus, and would be one of the most distant galaxies I’d observed… if I could find it.

Narrowing down the galaxy’s field by means of a small right triangle that lies SP the galaxy and a bright star S slightly F the galaxy, I began scanning the spot near the center of the POSS image of the galaxy. Sure enough, an exceedingly-faint, elongated spot, just above the threshold of direct vision, made its presence visible in just the place where the galaxy should appear. I rocked the scope slightly, noting the motion of the object with the foreground stars. Success!

Surprised and a little bit impressed, I watched the galaxy drift through the field repeatedly, recentering it whenever it got within a couple of arcminutes from the edge of the field. After ten minutes, though, I didn’t feel confident in taking notes on the galaxy; it was so faint in the poor conditions that I didn’t feel that the conditions would do it justice. Writing this ten months later, I regret not taking notes on the galaxy, but I would insist on taking a new set of notes on it in better conditions anyway. I switched to the 10mm Delos, noting an immediate but very subtle improvement in the view through the better eyepiece. Still, it wasn’t enough to persuade me to reach again for the recorder.

Rob stopped over at the Obsession, hoping to use it with his homemade spectroscope; he and Dan and Jerry had been using it for much of the evening in their own scopes. (Dan ended up buying it from Rob.) He asked what I was so intently observing; I offered him a look. He wasn’t quite sure he saw it, but was intrigued by my insistence in looking at barely-visible smudges.

I eventually yielded the scope to Rob for the spectroscope. He turned it upon Gamma Cassiopeiae (Navi), the middle star in the ‘W’ pattern of Cassiopeia, prodding me to take a look. I hadn’t looked through a spectroscope before, but knew what to look for—a color spectrum with a series of black lines in it, each line the signature of a chemical element present in the star.

This one was different, and I quickly saw why Rob had chosen this particular star: the star’s spectrum didn’t just contain the black absorption lines, it also contained several narrow glowing lines (particularly in the green end of the spectrum), showing that the star was also emitting radiation in an unusual manner; in this case, Gamma Cass was showing Balmer lines, those that indicated that the star was surrounded by a disk of circumstellar gas, and was in fact the prototype of the Be Stars, those surrounded by such disks.

This felt like actual science, as opposed to merely observing objects (no matter how detailed my notes from the observing). I could foresee myself buying one of Rob’s spectroscopes and spending some of my precious observing time cataloguing spectra. It was a brief chill of revelation, of the thought of contributing data points to the body of scientific knowledge. At a time when science seems to be slipping away from us, this almost felt like something forbidden, in addition to being inherently valuable.

I followed Rob over to Dan’s scope as we checked in on a planetary nebula. Planetaries are particularly good objects for spectroscopes, as the devices can immediately identify a stellar planetary amid a crowded field; planetary nebulae usually emit strongly in the lines of oxygen, (especially the O-III line, which is why an O-III filter is so effective in observing them). The particular planetary we observed was NGC 6752, the Emerald Nebula, known for its strong green/blue color (depending on the observer). Sure enough, the oxygen lines practically leapt out of the spectrum. For someone who’d dreamed his entire life of being an astronomer, this was exciting stuff!

At some point during our spectroscopic musings, I heard the familiar whine of a hair dryer. It hadn’t occurred to me that throughout my observation of PGC 70994, the Obsession might’ve been compromised by a fogged-over secondary mirror, but there was Jerry, drying off the secondary of his scope. Dew had indeed hit us hard; my table, my eyepiece case, and the shroud of the big scope were all dripping with it. I checked on the secondary and was alarmed to find a sheen of moisture across the outer 50% of its diameter. Several minutes with the hair dryer cleared most of the secondary, but there was little doubt that it would return; the beams of our laser pointers and red flashlights revealed considerable water vapor in the air.

Secondary cleared and sky conditions ever-so-slightly improved, I stopped back in on the NGC 7769 trio in Pegasus; I’d made a note to do so with the 20-inch. The view was impressive, although still not as much so as I might’ve hoped. Still, it was a galaxy trio, and a bright one, and seeing an entire distant galaxy in the eyepiece was awe-inspiring (let alone seeing three of them at once). I followed up with some other favorites: the NGC 470 trio in Pisces and the group around the fine double star 1 Arietis. Somehow, I passed up a look at Stephan’s Quintet.

By now, our collective energy level had flagged. it was nearly 1:00 AM; I had no idea how we’d managed to make it so long on a night that seemed so mediocre, if not downright discouraging to our endeavors. A phone alarm had gone off, signifying an astronomical event worth watching—in this case, the ingress of Io’s shadow as the tiny volcanic moon passed in front of the disk of Jupiter.

Transits of Jupiter’s moons across the planet’s face happen all the time; they aren’t rare. I frequently ignored them when we were “out in the field,” as I often had some eye-strainingly faint object in the eyepiece and didn’t want to have to find it again. But with little else of import to observe at the moment—and in fact otherwise preparing to call it a night—I dropped the Obsession onto the field of Jupiter and watched the tiny pinpoint shadow creep its way onto the giant planet’s face.

After a flurry of chatter, the observing field fell silent. The tiny black pinprick shadow drifted onward onto Jupiter; Io itself could be seen, brightly-lit by sunlight, against the darker bands of Jupiter’s atmosphere. The Great Red Spot seemed great again, after years of diminished size and shade, an unmistakable dark birthmark rotating out of view as the quiet minutes passed.

Soon after the GRS’ passage onto the other side of Jupiter, we started deconstructing our gear and observing site. Gear was broken down and packed into its designated slots, Tetris-like, in vehicles whose makers could’ve never considered such use for their creations. Cases were dried off before stowing; mental checklists were run through; oaths were occasionally uttered as parts refused to separate or small pieces hit the ground and hid among the rocks and grass.

I checked the secondary mirror before wrapping it in its foam sheath and shoving it carefully into the bass drum case it lived in. The secondary was so dewed over it looked as if it had been snowed on. The primary was still dry; the mirror box/rocker box was wheeled up the ramps into the Flex, with the drum case loaded in afterwards, fitting between the wheelbarrow handles on the mirror box. I left the lid off the drum case to allow the secondary to dry—never lock moisture in with optics, as glass can mold as easily as food, and mirror coatings are susceptible to the ravages of dew-locked pollutants and tarnish.

The last of the gear stowed, we exchanged notes on the evenings, followed by goodbyes and wishes for safe driving home. I’m sure I wasn’t the only one of us who took a lingering look around the Eureka clearing in a headlight beam—who knew when the gate might next be open for us to use the dear old site again? Places suitable for our esoteric purposes were harder to come by than they seemed, and such places so relatively near to town, yet so sufficiently dark, were rarer still.

The constellations of autumn, themselves such a source of nostalgia in my caveman brain, wheeled silently overhead. The wonders of the night, somehow undiminished by the comparatively-subpar sky conditions, still echoed through my awareness as if ongoing. I paused in the driver’s seat, door open, not wanting to leave the stars behind. Dan waited, his truck running behind me, for me to get moving.

I drove out of the clearing, along the ridge, somehow knowing that it would be a new year before I would again be taking notes on the mysteries of the universe.

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