Uncle Rod’s Astro Blog: Issue 607: Star Nests in Cygnus

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Uncle Rod’s Astro Blog: 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.

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