Issue 607: Star Nests in Cygnus

 

I had just finished last month’s AstroBlog, muchachos, when I was moved to begin the next one. The way the weather’s been this summer, and the knowledge it will likely get worse as September and October approach, impelled me to get back to work rather than take a break. One late July evening it ‘peared the sky might be good enough for the SeeStar, Suzie, to take a few of her little celestial snapshots. The Gulf beginning to churn with storms, I figgered I’d better get after it. I’d do some visual observing of the objects next break in the clouds. Whenever that was.

“Wut objects, Unk? Wut objects, huh?”  Well, Skeeter, I’ve kinda been on a roll revisiting the chapters of my urban deep sky observing book, The Urban Astrnomer's Guide, so I figgered I’d keep on keepin’ on with that for now. Specifically, with the Cygnus chapter, “Star Nests in Cygnus.” The ol’ Northern Cross would be near-perfectly placed in the east mid evening, and maybe the weather gods would indeed show your ever-hopeful Uncle some mercy.

By “star nests,” natcherly I meant “open (galactic) star clusters.” They were a favorite of mine when Miss Dorothy and I lived downtown in the original Chaos Manor South. They were the one deep sky object I could see easily and well. “Opens” became something of an obsession with moi—one time I set out to view all the clusters in Cassiopeia visible with a 12-inch telescope from an urban backyard (recounted in Urban Astronomer’s “The Cassiopeia Clusters”). That’s a lotta star clusters, campers, but, amazingly, I wasn’t tired of ‘em after that binge and soon went on to survey the Swan’s clutch.

Anyhoo, after checking-in to the Mobile Amateur Radio Club’s Wednesday Night Net, I stuck my head out of the radio shack and had a look. As astronomical twilight came in, it was just as Astrospheric had said: “Mostly clear.” But that blessed clear sky was accompanied by haze and poor, very poor, transparency. Oh, well, as Unk often says, “Ain’t nuthin’ to it but to do it.” I’d see what Suzie could pull out of a milk-washed Cygnus.

I had set the SeeStar up on my old Manfrotto tripod just before dark. She was leveled (a good idea if you want decent tracking) and ready to go. All I had to do was remove the scope cover I’d put over her to ward off the errant shower—they can show up any time of the day or night in the Swamp. Mashed the power button, and The Suze intoned, “Power on! Ready to connect!”

Zelda.

Once I’d connected to the girl with the iPhone app, next step was turning on her built-in dew heater. Sure felt like she’d need it on this night. I also installed the plastic dewshield I purchased some weeks ago. The heater would probably have been enough to keep the wet stuff at bay, but the dewshield also keeps ambient light off the girl’s objective. That was it. I headed inside, plunked myself down on the couch, and enjoyed the glorious air conditioning. Outside it was just under 90F at 2100 local.

The first target would be Messier 39, an old favorite located to the Northeast of shimmering Deneb. To get to it, I brought up the SeeStar’s star atlas on the iPhone, searched for and located M39, and chose “gazing.” Suze performed her usual initial calibrations, and, in a minute or three, headed for the cluster. Our target was obvious even in the short “gazing” exposures. As usual, she had placed it dead center in the frame. I started the exposures, ten second exposures, rolling in, and headed to the kitchen to retrieve some cold 807s (for me) and catnip (for the felines).

All Unk and the cats did for the balance of the evening was choose the next target when the stacked results Suzie delivered to my phone looked good enough. Given the conditions, I didn’t want to go too long. Also, I hoped to cover all the targets in one night, and, so, limited each open cluster to 10 minutes or less. With just a few minutes exposure, they looked purty derned good. I did go a little longer on globular cluster M71 and M27, The Dumbbell Nebula, my pièce de resistance for the evening. Suzie did a nice job given the conditions.

Anyhoo, that was part one of the observing for this one. The next morning, Miss Dorothy asked me if I didn’t miss being outside with the telescope, “Not on a night like that one,” was my quick reply, but, truthfully, I did miss being under the stars. That came some days later when we got another clear—if no more transparent—evening.

Into the backyard went the 6-inch SkyWatcher (who whispered to me her name is “Brandy,” which seems to fit). It was pretty much a semi-scrub. Out there in the humid heat, I refamiliarized myself with the SynScan Pro app on my iPhone that serves as Brandy’s hand control. Once I got the hang of it, gotos were fine, even with just a two-star alignment. But you know what? The punk sky conditions were just too much for the girl.

An extra inch of aperture compared to Charity, the ETX 125, helped some, but not enough. To be honest, it was hardly noticeable. And Charity certainly has a contrast advantage. In the haze, M13 was a slightly grainy blob and M3, which is getting low by 2100 local, was almost invisible. The gap between what I could see with my aged eyes and what young Suzie could see with her electronic sensor was vast. Ground truth? Neither Charity nor Brandy would be good enough this time of year when I wanted to get semi-serious about visual backyard deep sky observing.

I was disappointed, but not much surprised. Thinking back to my initial visual testing in the backyard of New Chaos Manor South a decade ago, that was exactly what I’d experienced. Yes, of course the skies are better than they were downtown. On a good, dry night, magnitude 5 stars are visible in this suburban/country transition zone. On a dry night, which is something we don’t often get in spring and summer (and increasingly, fall) in Possum Swamp. On a humid summer’s eve, the heavens look much like they did from the original Chaos Manor South in the Garden District.

How much telescope is needed for rewarding deep sky observing under these conditions? The aforementioned testing showed that often even 8-inches wasn’t enough. At 10-inches, however, the improvement was marked. The deep sky went from “kinda icky” to at least “interesting.” It looked to me as if the visual scope for work from my backyard would have to be my 10-inch Zhumell (GSO) Dobsonian, Zelda, at least until summer wanes and some semblance of autumn comes in.

Miss Zelda is a great telescope with a surprisingly excellent primary mirror. No, she’s not grab ‘n go in any shape form or fashion, but it’s no problem to leave her outside under a scope cover in our secure backyard as long as violent thunderstorms are not forecast. The only question was whether I could still get her safely into the backyard without damaging her, myself, or both of us.

One mostly clear if hazy afternoon, I found the answer is still “yes.”  To begin, I cautiously removed Zelda from her rocker box—first time I’d done that in several years, I was embarrassed to realize. Heavy, but not too heavy; at least not when just lifting her out and standing her up on her (sorry, girl) rear end. Well, there would be a problem if somebody decided to push the tube over with a paw, which is why I locked the felines out of the sunroom to their outrage.

Moving the rockerbox/groundboard to the backyard was simplicity itself. There’s a nice big handle on the front. Then, I returned to the tube, lifted it with one hand on the rear cell and one arm around the middle of the OTA. It’s harder to describe than do but suffice to say that while I wouldn’t want to waltz Miss Zelda across the dance floor, carrying her ten meters into the yard was no problem, even considering I had to go down three steps.

The verdict? The tube is heavy. Heavier than I remembered. Eventually I’ll likely have to use a hand truck to get the scope into the back 40. But if I must do that, I will do that. The last 30 years, a 10-inch has come to be thought of as a “small” telescope. It’s not. One is a powerful performer on the deep sky.

In the 1960s, and even into the 70s, for the amateur astronomer a 10-inch was a big, even huge, telescope. It is, in fact, the largest instrument used regularly by that sainted dean of deep sky observers, Scotty Houston. As many of us age out of owning or even dreaming about owning 20 or 25 or 30-inch telescopes, I think the humble 10-inch might regain some of its lost glory. Anyhoo, I have no intention of giving up one’s horsepower as long as I can safely manage a "10."

Zelda mostly ready to go, I plugged in the battery pack that powers her cooling fan; she’d been in the air-conditioned house, and, while not as bad as it had been, the weather wasn’t exactly cool as the afternoon waned. Next? A little TV with the cats until the long, slow DST hours between now and astronomical twilight passed…

Nota Bene:  The order of the objects I looked at with Z was the same as in the book, Urban Astronomer.

M39

It took me a long time to learn to appreciate this galactic cluster, which lies well away from the Northern Cross asterism, about nine-and-a-half degrees to the northeast. On a summer’s eve’ as a kid astronomer, I’d maybe take a quick look at it and move on. All it was was a patch of medium-bright stars, with the more brilliant ones forming a triangle. It was soon in the rearview mirror as me and my fellow members of the Backyard Astronomy Society continued our fruitless search for the veil nebula with our long focal length three and four-inch scopes.

As the years rolled on, and I turned more appropriate instruments on M39, my opinion of this magnitude 4.6 cluster began to change. What’s “appropriate”? A scope/eyepiece combo that puts some space around this half-degree size group. Oh, and aperture doesn’t hurt either. Enough dark space to frame it, and enough aperture to begin to show off the magnitude 12 and dimmer stars that lurk inside the triangle of magnitude 6-range suns, and you begin to have something.

While M39 will never be a showpiece, yeah, it is something. How do you look at it? On this evening, it showed off plenty of stars in Zelda with a wide field 13mm ocular, but it just wasn’t pretty.  I knew the solution:  more field, less magnification. Inserting my 35mm Panoptic into Zelda’s focuser rewarded me with the, yes, awful pretty. All those dim stars higher magnification revealed had disappeared, but just as in Urban Astronomer, where I switched from a "big" scope to my old Short Tube 80 (mm) refractor, I thought it was worth it. With plenty of space around it, M39 it looks more distinctive and just better.

How about the SeeStar, Suzie? As you can see, she’s a mite field-challenged for this one given the geometry of her chip. Oh, she shows scads of stars. Everywhere. Yes, the bright triangle stands out. But the cluster doesn’t have much snap. It doesn’t pop out of the background as it does with a wide-field visual scope.

M29

Something puzzled me and my BAS buddies back in the day. There’s only one other Messier object in Cygnus, a rather lackluster galactic cluster that pales compared to some of the other sights in the Swan. Why? Who knows, and be that as it may, with M29, it is what it is.

Once you’re on M29, which lies just under two degrees south-southeast of bright Sadr at the Swan’s heart, don’t expect much. What I had in Zelda with a 13mm Ethos eyepiece was a little dipper-like asterism of stars maybe ten minutes across. I do sound fairly enthusiastic in the book, “Four bright stars stand out extremely well at 48x in the 4.25 inch…I can see seven other cluster members despite scattered clouds and fairly heavy haze.”  And that is about what I saw in similarly heavy haze with Zelda. Oh, a few more dimmer suns were visible, but not many. As I also say in the book, after 6-inches of aperture, M29 doesn’t improve much.

Suze? I devoted a mere 6-minutes exposure to Messier 29, and that was all it took. Even in that snapshot, many dim background stars are visible across the frame that weren’t seen in Zelda. The cluster itself looks much the same; it sure stands out from the background. What helps this magnitude 6.6 group? That small 10’ size. Dare I say it? It’s almost photogenic.

M71

Despite titling this chapter “Star Nests in Cygnus,” I did take some detours, including to nearby Sagitta’s M71, which is 5 degrees south-southwest of its famous neighbor, M27, the Dumbbell Nebula. The only claim to fame M71 has is that while it is a globular cluster, it doesn’t look much like one, appearing to be a rich and compressed open cluster like M11. There was supposedly some debate over its status for a while, but I’m skeptical about that. One look at M71’s color-magnitude diagram says “globular.” And that is what it is, a (very) loose Shapley-Sawyer Class XI glob.

So, what’s it like visually? You’d think this magnitude 8.6 object would be as challenging as Lyra’s M56 or Coma’s NGC 5053. Nope, it’s easier with smaller aperture scopes due to its small, 7.0’ size. It was certainly visible with a 6-inch telescope on good nights. As I observe in Urban Astronomer, though, more aperture helps. In the 12mm Ethos in the 10-inch, it’s an obviously resolved little clump o’ stars.

In pictures, this wee globular is pretty and interesting if not spectacular. Missy Suzy easily resolved hordes of cluster stars set against a very rich background. You know what M71 looks like in Suze’s shot? It looks amazingly like the Wild Duck Cluster. But, no, M71, which I’ve heard called “The Angelfish Cluster” (?) in recent years, is a globular star cluster, y’all.

NGC 6910

And that exhausts the Messiers. What’s left galactic clusters-wise is, yes, NGC clusters. Now, now, don’t take on like that. Some of ‘em ain’t that bad, like 6910 which those long years ago I thought was, “A real surprise with the 8-inch f/5! Very nice indeed for a non-Messier…about 10 – 15 stars visible.” In Zelda with the 150x delivered with an 8mm Ethos, what was in the field was a scattering of dimmish stars around an acute triangle of 9 – 10 magnitude ones. As on that long ago night, there appeared to be around a dozen dimmer stars visible.

In the SeeStar? When looking at an image of a galactic cluster, it’s hard to say what’s a cluster member and what isn’t. Maybe 25 – 30 likely member suns? At any rate, unlike some NGC opens, it is “well detached” from the background. One look at the picture and you see the cluster.

NGC 6866

What did I see when I took a gander at 6866 with my old Meade 12.5-inch way back in the 1990s (it seems odd to say that; lately it seems like yesterday)? “Beautiful field with the cluster looking like a miniature M39.” And that’s still accurate; that was also my impression with Zelda: a vaguely triangular shape of suns (I’ve heard this group called the “Kite Cluster”).  This magnitude 7.6, 6.0’ size cluster is another NGC open that’s easy to see.

Suzie did a nice job on this one in only 5 minutes. Yes, there are hordes of background stars, but the cluster is again easy to pick out. Maybe it even looks a little more like a kite than it does visually, with two curving arcs of stars that aren’t as noticeable visually forming the sides of the kite.

NGC 6819

This is yet another example that makes a lie of the old saw, “All NGC open clusters are the same—boring.”  The somewhat well-known Fox Head Cluster has a combined magnitude of 7.6 and covers a mere 6.0’ of sky. In the book, I pronounced it, “A very attractive NGC open cluster in the 11-inch Schmidt Cassegrain…looked more oval than square.” In Miss Z, the impression was, conversely, a diamond shaped pattern of many tiny stars.

Inexplicably, I didn’t get NGC 6819 on my observing list and, so, didn’t get a SeeStar image.

NGC 6834

For this one, we leave the “cross” area of Cygnus and head towards Albireo. Our quarry is a small magnitude 7.8, 4.0’ across group. My impression in the 10-inch Dobsonian was “small and dim,” and that was also what my old 11-inch SCT showed in the glorious Day: “Small and dim. In the 11-inch scope, I see a 5.0’ oval of faint stars…crossed by a prominent line of brighter stars.

Which is exactly what Suze pulled in in 6 minutes. She did pick up many, many even fainter stars I couldn’t see visually, and in her shot, the cluster begins to assume a more triangular than oval shape.

NGC 6830

And yet another good NGC open star cluster glowing softly at magnitude 7.9 and extending 8.0’.  For this one, I again ventured out of Cygnus to another small nearby constellation, Vulpecula, The Little Fox, home of the abovementioned Dumbbell. In Urban Astronomer, I found 6830 to be, “Very distinct from the rich beautiful field it is set in. Rectangular in shape.” Today? Much the same. A vaguely rectangular or diamond-shaped pattern of a fair number of magnitude 9-10 stars and many dimmer ones. Oh, for some inexplicable reason, some call this “The Poodle Cluster.”

In the Suzie-shot, the cluster is identifiable around a diamond of brighter suns, but, admittedly, it is beginning to recede into the background. In the image it’s still easy to pick out but proceeding toward “not well detached.”

NGC 6823

This magnitude 7.0’, 10.0’ size group is involved with a large complex of nebulosity which was totally invisible in my urban skies. What was visible was a nice enough galactic cluster: “A nice medium-sized open cluster in the 8-inch f/5.” I also observed that the cluster looked like a miniature Scorpius. I didn’t see that on this latter-day night with a 10-inch. What I saw was a rather shapeless sprinkling of magnitude 10 and dimmer stars.

That is what I saw with the SeeStar as well. I didn’t expose for long, and didn’t use a filter, so any nebulosity that might be there wasn’t visible. I do note some star chains that give 6823 a vaguely flower-like shape.

Albireo              

I ended each chapter of Urban Astronomer with a double star. For this chapter, Albireo was obviously it. Now, the lustrous blue and gold “Cub Scout Double” is not an object for a 50mm f/5 scope, but Suze still did a fair job, showing a pair of strongly colored stars.

And that was that.  Oh, on my imaging night, I did send Suzie to M27 to see what she could do, and she did a very fine job for a wee telescope. All that remained was to throw a cover over Zelda (I didn’t feel like—ahem—wrestling with the girl at the tail end of a long and hot evening). She’d be fine in our secure backyard, and getting her back to the Sunroom would be a far less daunting task in the morn’.

So…I saw some cool sights and found I could still (fairly) easily set up the 10-inch.  This night was a win, then, especially since I’d had a good time, and it had brought back some nice memories of my Urban Astronomer runs.

Next up? Another observing article, but we’ll give Urban Astronomer a rest in favor of something (sort of) new.