Smoke and Mirrors

I’ll skip ahead to the end:

August’s observing run should’ve been a good one—skies were clear for more than three weeks straight—but the smoke from endless Western forest fires wiped out nearly the entire month, rendering the clear skies impenetrable for all but the naked-eye planets, the Moon, and a few of the brightest stars. As a result, one of the year’s last useful months for observing (based on past years) was a washout, excepting the first pre-Third Quarter Moon night.

[Small potatoes, of course, compared to what the people actually living through the fires were dealing with.]

I’d intended, during the August run, to make further headway in the planetary nebulae and open clusters of the summer Herschel objects. With a short night that first time out—given the early Moonrise—I’d also planned to take notes on many of the globular clusters in the Messier catalogue that I hadn’t yet taken notes on (fourteen of them!) so that I could say that I’d “gotten” every globular cluster visible from the northern hemisphere barring those in the Palomar and Terzan catalogues (and I’d also observed several of those). Not knowing it was to be my only real observing of the month, I set this first night aside for the Messiers.

Given that it wasn’t Herschel hunting, I also had an additional component to the evening’s plan: to give my newly-refurbished 13.1″ Coulter Dobsonian—my second telescope, bought back in 1990 and christened by Mrs. Caveman as “The Angel of Death”—its second first light, and its first at a “real” dark site. My 8″ Celestron SCT, my very first telescope, had been out to Eureka Ridge already, so it was only appropriate that its bigger brother had a chance to revel in the Bortle 3 skies of the Ridge.

To go along with the use of the old Coulter (and Paracorr Type 0, a necessity at f/4.5), I stuck with my old TeleVue Plössl eyepieces as well. These were a point of lighthearted derision among my fellow observers, in contrast to the higher-tech wide-fields we all usually used. They were also somewhat difficult to get used to after having used 68-82˚ eyepieces as my mainstays for the last fifteen years or so. Nonetheless, the Plössls were (as always) commendably sharp, and their narrower fields of view still quite comfortable to observe with in the old light bucket. In addition to the 17mm with which I took my notes, I also used 26mm and 40mm Plössls to help compensate for the less-accurate pointing offered by the red-dot finder on the Coulter.

08/02-08/03/18

EUREKA RIDGE
MOON: 21 days (71% illuminated); rose at 11:42 PM
SEEING: 7
TRANSPARENCY: 7; MW well-defined; Dark Horse much less so than on previous nights
SQM: 21.4
NELM: not checked
WEATHER CONDITIONS: temps falling to low 60s; considerable dew, clammy

Others present: JO, OG, Leticia, JH (Justin)

All observations with a 13.1″ f/4.5 Coulter Dobsonian, 1.15x original Televue Paracorr, and 17mm Televue Plössl (with Paracorr, 101x, 0.6˚ TFOV).

10:14
M53 (Com): The sky isn’t 100% dark yet (it seems to be a habit of mine to start so early). This is a pretty “tight” cluster, perhaps CC 5; a satellite crosses it as I take notes on it. The cluster is 4.5′ in diameter, with a granular 3.0′ core and outliers stretching out to 9′. The well-resolved halo comes to the core pretty quickly. There’s a row of stars running along the N side of the cluster’s periphery, and on the SF edge of the halo is an area devoid of resolved stars. The core extends slightly into the halo on the NP and SF sides. About 25 stars are resolved in the cluster, with a prominent star just on the NF edge of the core. SF the cluster by 10′ is a brightish pair, 9th– and 9.5-magnitudes, separated by 1.5′, with the fainter the more N-ward; these form an isosceles triangle with an 11.5-magnitude star that’s 3.25′ due F and between them. SP the cluster by 15′ is a 9.5-magnitude star. The much-fainter NGC 5053 is about a degree SF, and is plainly visible despite the not-yet-dark skies.

10:33
M3 (CVn): One of the finest globulars in the sky, and this might be the best view I’ve ever had of it. It’s a glorious hive of stars, much more impressive than M53 (which is an underappreciated object nonetheless). The core, which has many stars resolved across its face, is about 4.5′ in diameter. The cluster’s halo is similarly well resolved and extends to 12′, with outliers to about 15′. The core looks a bit offset toward the SF. Many stars are resolved in M3, with notable outliers to the NP and SF; the halo is “not in a hurry to get to the core” (according to my notes), giving a CC of about 6. The cluster sits inside a right triangle whose right-angle corner is a 9.5-magnitude star NP the cluster by 7′; an arc of faint stars runs P, then N-ward, from the cluster’s center over to that star; 12′ F slightly N that 9.5-magnitude star is a 10.5-magnitude star; the third vertex of the triangle is an 8th-magnitude star S very slightly F the cluster by 14′. The triangle’s hypotenuse is 21′ long.

10:48
M5 (SerCap): An awesome sight! The old Coulter is reveling in these dark skies, and M5 is a fantastic object for it to dwell on. The core is almost uniformly-bright, 3.25′ in diameter (smaller than M3’s); the halo extends to 10′ but outliers stretch to about 18′. M5’s outliers stretch in chains, one of the most prominent of which stretches to the SP (with an extension to the SF) and another that loops from the core to the NF; a third extends from the NP of the halo toward the N. These give the cluster an almost spiral shape (alert Lord Rosse!). The P side of the cluster seems flatted against the arcs to the SP and NP, like a swarm of gnats hitting a windshield. There are too many stars resolved in the cluster to count. To the S very slightly P (where that SP arc begins) is an 11.5-magnitude star that is 5′ from the cluster’s center; the arc stretches S and then SF and is 7′ long. Another brightish (12th-magnitude) star is due SF of the core by 7′.  A grouping of seven stars runs in a zigzag along the P side of the field, halfway from the cluster to the edge, toward the SP of the cluster. F the cluster and extending to the SF is an arc of four stars that begins at an 11th-magnitude star 18′ F the cluster and runs SP, S slightly P, and then S, ending SF the cluster; the others in the arc are 12thmagnitude. Just outside the field, 24′ SF the cluster, is 5 Serpentis: a 5th-magnitude primary and an 11th-magnitude secondary, with the primary N very slightly F the secondary by 10″.

11:35
M14 (Oph): A gorgeous cluster that’s often overlooked in favor of M10 and M12 to the west, M14 is the personification of a “powdery” cluster, covered in a dusting of uniformly-faint star-points. The cluster is 6′ in diameter, with a core that’s 2/3′ of that diameter and a scattering of about 20 tiny halo stars on a smooth background gradient. Just outside the F very slightly S edge of the halo is a pair of 14th-magnitude stars separated by 20″. NF the cluster by 12.5′ is the right-angle vertex of a triangle; this is the closest vertex to the cluster and is 10.5 magnitude; the other two in the triangle are 10thmagnitude; one is N of the right-angle vertex by 2.5′ and the other due F by 4.5′. NP the cluster by 15′ (on the edge of the field) is a 9.5-magnitude star; N of that star by 9′ is a 7.5-magnitude star. SP the cluster by 13′ is the brighter of a pair: the brighter is 9.5 magnitude and the secondary 11thmagnitude; the secondary is F slightly S the primary by 1′. 15′ S of the cluster is an 11th-magnitude star.

11:55
M70 (Sgr): The last one for tonight, as the Moon is already up (albeit blocked from view by the ridge). This is a small, less-resolved cluster sunk in the bottom of the Teapot. It’s only 2′ across at the halo, with a 20″ core region that’s almost stellar at first glance. A few threshold stars skirt the periphery. CC is perhaps a 6. NF the cluster by 1.67′ is a 12th-magnitude star that has a 13th-magnitude star N of it by 30″. S slightly F and running due SF is a line of four 9th-magnitude stars that’s 6′ long; the P-most star in the line is 15′ S slightly F the cluster and has a 12.5-magnitude companion 12″ N very very slightly P. P slightly S of the cluster by 14′ is an 8th-magnitude star that has a 10.5-magnitude star S very slightly F by 0.67′. N of the cluster is a line of stars extending 15′ to a 9.5-magnitude star NF the cluster; the other stars in this arc are 10th/10.5-magnitudes; one of the 10th-magnitude stars is due N of the cluster by 3.5′.

I filled in the spaces between globulars with casual browsing of some of the usual summer targets. The refurb job on the Coulter—replacing the broken mirror cell (which got damaged upon being shipped from Anchorage, Alaska to Carbondale, Illinois) with a sleeker, more-adjustable version and replacing the original plumbing-parts focuser with a JMI Crayford—had resulted in the scope being extremely top-heavy, so I had Velcro-d a number of counterweights to the bottom end. The scope still needed help staying balanced close to the horizon, so looking toward the center of the galaxy was a little more awkward than I’d hoped. (The next phase of the plan is to move the altitude bearings on the scope to help rebalance it, and installing the 11 x 80 finder that I’d bought for it 25 years ago.) Still and all, the “old red beater” performed superbly at lower powers and none too badly at the higher end.

Had I known that the smoke from the burning West was going to wipe out the rest of the Moon-dark phase, I might’ve felt more urgency to go out the next night, which was also reasonably clear. Or I might’ve brought Bob the Dob out for adventures in Herscheling instead of giving the Coulter some glory. In any event, aside from a few casual moments of stargazing—including catching first light on Robert A’s 3D-printed 8″ binocular telescope at the College Hill Reservoir here in Eugene—that single evening at Eureka was the total of dark-sky observing for August: more than in 2017, when I went back to Carbondale for the eclipse, but nothing like our usual homestretch run. With September always being a crapshoot weather-wise and October usually seeing the beginnings of “monsoon season” here in the valley, August’s smoke out may have brought a close to our large-scale observing for 2018.

 

 

 

 

 

 

 

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