So Fair the Sky

Between the first weekend of October and the last weekend of February, stargazing in the Willamette Valley largely ground to a halt. Intermittent breaks in the clouds and rain allowed some of the other EAS Irregulars to sneak in some observing breaks, but these were mostly short and had lesser skies than our spring or summer sessions. And with my work schedule, I couldn’t even get out for those.

I watched the e-mail list with envy as the sky for those five months occasionally took pity on photon-starved Oregonians and gave them succor—those nights that proved to be both clear and Moonless always happened during the week, when I had work the next morning. (Yes, the sky did get dark early enough that I could eke out a few hours’ observing before it got too late, but I was usually too tired from a 5 AM wake-up call to risk an hour’s winding drive home in the dark.)

So I waited for clear skies, absent Moon, and weekend to coincide. And, finally, they did.

It took until the last weekend of February, and the forecast gave us only a few hours before clouds were to take over again. But a few hours would do; I had three planetary nebulae to take notes on from the Astronomical League list and one from the Deep Sky Forum, and any other time left over would go toward the winter/early spring highlights that I hadn’t seen in a whole year. The Eagle’s Rest amphitheater site had the best Clear Sky Chart, so off we went.

I arrived first; Dan B, Jerry, Loren, and Robert also made the trek out, and we kept one eye on the still-cirrusy sky as we assembled telescopes and staked out our small individual spaces in the roadside clearing.

All of my “required” nebulae were in the Index Catalogue (IC), which was a supplement to the better-known New General Catalogue (NGC). Two of these were in Perseus, as was Bohm-Vitense 5-3, an intriguing planetary that featured as the Deep Sky Forum’s Object of the Week on January 9th. The fourth nebula for the night was IC 2165 in Canis Major, for which I’d taken a sparse set of notes several years ago.

EAGLE’S REST (amphitheatre)
MOON: 24 days (rose at 3:32 AM; 28% illuminated)
SQM: 21.2
NELM: not checked
WEATHER CONDITIONS: temps to 29F; no dew; air still; cold
OTHERS PRESENT: JO (20”), DB, RA, LR (18”)
All observations: 12.5″ f/5 Discovery Dob, 14mm ES 82˚ eyepiece (112x, 0.7˚ TFOV), 7mm TeleVue Nagler (225x, 0.36˚ TFOV), or 4.8mm TeleVue Nagler (323x, 0.25˚ TFOV) unless otherwise noted

IC 2003 (Per): Here at the amphitheater with the 12.5-inch, and I’m looking at IC 2003 in the back foot of Perseus; it’s surprisingly not just easily visible, but easily visible as a non-stellar object a few arcseconds in diameter, perhaps 8”. The nebula very clearly has a brighter center that looks stellar, and at first it seemed to display a little bit of maybe bluish (maybe greenish) color; it’s so small it’s hard to tell, but it seems like it did have some actual color to it. It also has a faint star just off the P slightly S which is 13.5 magnitude, and also due N of it by 1.3’ is another 13.5-magnitude star that has N slightly P of it by 0.67’ a 13th-magnitude star. The nebula and its companion star form the S-most vertex of a diamond: due N of it by 5.25’ is a 10.5-magnitude star; from the nebula almost due NP by 3.25’ is an 11.5-magnitude star, and then N slightly F by 2.75’ is a 10th-magnitude star that has an 11th-magnitude star F very very slightly S of it by 0.75. SF the nebula by 2.25’ is an 11th-magnitude star that’s an outlier from the diamond. N very slightly F by 17’ is the brightest star in the field, which is 8th magnitude. The UHC filter really brightens the nebula; it’s now the brightest object in the diamond, just slightly brighter than the 10th-magnitude star to the N slightly F. It’s still very much a non-stellar object, and I’m still not totally sure, as with the unfiltered view, that there’s anything fuzzy or diffuse to be seen there. This is going to be another one with which the magnification makes all the difference. So with that said, let’s try the O-III. 

The conversation, as it usually did, took numerous convoluted paths as we observed; somehow, as I was swapping filters, it ranged from new names for the Eskimo Nebula (NGC 2392) (my suggestion was “The Itel’men Nebula,” after the Itel’men people of Kamchatka, whose language I had studied quite a bit while working on my Master’s degree; mentioning Kamchatka of course required a digression on the game Risk) to the new astronomy ladder I’d gotten for Christmas, to the obscenely-high power Jerry was using on NGC 2392, to a quality assortment of Monty Python references, and all of it caught on my audio recording. And in all of this, I managed to not only lose the nebula, but to make the mistake that had been inevitable for so long: I got my O-III filter stuck in my 14mm Explore Scientific Nagler clone… which just happened to be my workhorse eyepiece.

The amount of profanity that ensued would’ve made George Carlin or Frankie Boyle wince. Dan, Jerry, and Loren all took turns trying to extricate the filter; we even used a pair of pliers, writing the old filter off as a loss. Nothing worked—the filter remained stuck. One planetary in and I was ready to call it a night. Fortunately, Dan came to the rescue, loaning me his 14mm Explore to use in place of mine. I went sans O-III for the night, not thinking that I simply could’ve swapped my own eyepiece in when the time came to use the O-III, using only the UHC for filtration. Magnification always beat filters anyway, in my experience, so perhaps I could make it work.

It took me several minutes to recapture the nebula, cursing all the while. I apologized to the others later.

With the O-III stuck in the 14mm, we move straight to the 7mm, where the nebula is very much a non-stellar object with some real dimension to it; it definitely has a bright core region, but my certainty that there was a central star is no longer quite as obvious. There’s now a fringey halo visible, but the distinction between the brighter inner region and the fuzzy outer halo is not that great, even at this magnification—not like they are in some of these; this one just kind of smoothly bleeds from concentrated to unconcentrated moving outward from center. The 10th-magnitude star to the N slightly F has a 13.5-magnitude star 0.75’ P very slightly N of it  (this is a lot more visible with this magnification than in the 14mm), and the P-most vertex also has S very slightly F it by 15” is a 13.5-magnitude star (which I don’t know how I missed earlier). That’s a really good little tiny nebula; I wish they were all this good at higher powers! With the UHC, the inner region definitely brightens up in relation to the outer parts, so it’s definitely showing that distinction better, and there’s no real chance to say that there is a central star in there with the UHC in. I feel as if one should be visible among all the middle region there, but I just can’t ferret it out; it’s probably only just a shade brighter than that core region. With the 4.8mm… oh yeah, that’s excellent! Focus is fiddly at this magnification, but this is a great very small planetary, one of the better ones I’ve seen. The fuzz is just all the more obvious at this magnification. It almost appears to be a little lopsided on the N slightly F edge, as if there’s an embedded stellaring or very faint star there. Wow!

With my groove slightly back, it was only a short hop-skip-jump—just over two degrees—to my second nebula, IC 351.

IC 351 (Per): This one, IC 351, is pretty near IC 2003, and it’s somewhat smaller than IC 2003 (6” vs 8”), not much above stellar, but it still in the unfiltered view has a funky non-stellarness and a very slightly bluish tint [rather than an actual color] to it. And it’s very, very slightly diffuse on the edges, unlike IC 2003, which was very clearly pretty well-defined at lower magnifications. This one could in fact be a little more distant version of 2003. I found it using a very small triangle that’s F somewhat S of it, the brightest star of which is about 3.5’ F somewhat S of the nebula; it’s magnitude 9.5, and it has SP by 0.5’ a 12th-magnitude star that has a 13th-magnitude star P somewhat N of it  by about the same distance, and then from the nebula S by 3.25’ (and so forming an almost equilateral triangle between the nebula, the little compact triangle, and the star here) is a 12.5-magnitude star; those stars form an almost equilateral triangle—it’s not perfect, but which of us is? N of the nebula by 6.5’ is an 11.5-magnitude star, and then further N of the nebula by 17’ is a very close pair that has to be a double; the S-most of those two is what I measured from, and those are both 10.5 magnitude, separated SF-NP to each other by 6”. The seeing is just a little bit unsteady enough for me to be unable to tell if one or the other is very slightly brighter. S of the nebula by 13’ is a 9th-magnitude star that has an 11th-magnitude star NP by 0.25’. The UHC filter definitely brightens things up contrast-wise; it doesn’t do much else to the view at this magnification, but the nebula’s now almost the equal of the 9.5-magnitude star to the F somewhat S. So we’ll remove the filter and go with the 7mm, which among other things really brings out the triangle and the non-stellar quality of the nebula, as well as the fact that there’s a 15th-magnitude star P slightly N of the nebula by 0.3’. Even at this magnification the nebula resembles a distant version of IC 2003Adding the UHC filter nets a great contrast gain! The halo is a little more apparent now with the filter; in many of these, the fringe disappears when I put the filter on, but this one responds “normally.” I think the central star is more apparent in this one, but it’s still hard to pick out of the interior. This one has a better-defined core/halo distinction than IC 2003, with the halo standing out much better with higher magnification. With the 4.8mm Nagler, the seeing isn’t helping at all, and I’m not able to focus enough for more detail. That 15th-mag star really stands out better, though.

I noticed that Dan’s eyepiece had no problems with the UHC filter….

I’d intended to pick up Bohm-Vitense 5-3 while in the area; a much fainter nebula, it lay up in the northern regions of Perseus. But it also currently fell right into the Eugene light-pollution dome, which was much worse at the amphitheater than at Linslaw; even if I could manage to winnow it out of the light pollution, it wouldn’t be worth taking notes on it when I could wait and pick it up more on the rise in the autumn. There were patches of cirrus here and there in the sky, too, as the CSC had said there would be; we probably didn’t have long before the sky was crudded over.

I had already done two of the three nebulae I’d had on my agenda for the night, and the third wasn’t really an option. So I swung the scope down to Canis Major and IC 2165, just past the meridian. My previous set of notes on this one wasn’t adequate, so now was as good a time as any to correct that problem.

IC 2165 (CMj): Up near The Greater Dog’s head is IC 2165, and it’s not as easy a find as the previous two; there are fewer landmarks here, and it’s a little less obvious than the others (2003 was the easiest). The nebula still yields up at a cursory glance that it’s non-stellar. It has a Baby-Eskimo profile to it at 14mm. There’s a very bright, very tiny core present with a possible (likely?) central star and a very thin, faint bit of outer fuzz (less than the other two). N somewhat P the nebula by 6’ is an 11th-magnitude star, then N very slightly F the nebula by 3’ is a 12th-magnitude star; there’s a 13th-magnitude star F very very slightly N of the nebula by 2.67’. The nebula and the two stars almost make an equilateral triangle. N very very slightly F the nebula by 1’ is a 13.5-magnitude star. 12’ F very very slightly N of the nebula is the brightest star in the vicinity, which is 8.5 magnitude, and that star is the S-most in a diamond that was my landmark for finding the nebula: 2’ N very very slightly P that star is a 12th-magnitude star; there’s a 10.5-magnituide star 1.67’ F very slightly N of the first star; and from the first star 2.5’ P somewhat N is an 11th-magnitude star; those make up the diamond, and were measured from the brightest/first vertex. So with the UHC in, the nebula leaves little doubt that it’s not a star; the filter really boosts the contrast. The nebula appears concentrated to a really sharp central star or point, and is as bright as the brightest star in the diamond; it’s lost a bit of its non-stellar character, but has a little bit of a “blinking” effect where it becomes more non-stellar the more you look away from it (shades of NGC 6826). With the 7mm, the nebula a lot more concentrated, maybe 2” across, much smaller than IC 2003 and less than half the size of IC 351, with no real color (I wasn’t sure at first). With the UHC added: aside from the contrast increase and the 7mm, the nebula is still not showing any nebulous character (although it’s still obviously non-stellar); although it may be the worsening seeing at fault. Moving to the 4.8mm Nagler really brings out the non-stellar character to its best; the nebula has a very tenuous, fuzzier outer edge, although the seeing is breaking down at this magnification. The central star, which seems like it’s just below the threshold of visibility, is not really discernable at this magnification.

By the time I finished my notes on IC 2165, much of the western sky was under a blanket of cirrus (including M42, the great Orion Nebula, which I hadn’t looked at in nearly a year). I poked around in Leo for a few galaxies—NGC 2903, Hickson 44–and over into Cancer for a brief look at M67, even as the others started disassembling their gear. I made sure to give Dan his eyepiece back before he got his eyepiece cases stowed.

The amphitheater has two advantages over our other sites: it has the most-usable southern horizon among them (a smaller window, but less haze than Linslaw has in the very low south) and the shortest drive home. This latter was particularly welcome on the night, as I spent most of the drive stewing over the damned O-III filter. I was home by 10:15 and on the internet at 10:30, looking for solutions, and by midnight had ordered a filter wrench from ScopeStuff and an Astronomik O-III filter from High Point Scientific (courtesy of a Christmas gift certificate from Dan). The wrench, a 3D-printed open ring with handles, made short work of the recalcitrant filter, removing it intact from the barrel of the 14mm. The Astronomik was briefly backordered (like so much astronomy gear these days, thanks to the pandemic), and wouldn’t arrive until galaxy season was well underway, and few suitable targets were available. Appropriately, our next observing opportunity would also only arrive once galaxy season was underway.

But at least I couldn’t complain about the ancient Lumicon anymore. Now, I just had to do something about the problematic eyepiece barrel….

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