Sunday, June 26, 2016
Issue #499, Getting a Black Eye
But in a good way,
as in gazing at the wondrous Blackeye Galaxy, M64. Yep, here is another Messier
installment that features a showpiece, if one that’s maybe not quite as
spectacular as last week’s M57. Actually, we’ve got not just one showpiece this
morning but—count ‘em—three. There
are two other goodies in this group that, while maybe not as pretty
individually as M64, pack a real wallop when seen together: M65 and M66.
‘Course, to see these beauties you gotta have something to
look at ‘em with. I’m not talking about your telescope. We’ve covered that
ground a couple of times already. What I am talking about is something that is
often claimed to be at least as important as the telescope, eyepieces.
What do I like for Messiers ocular-wise? Those who know me
know I am addicted to ultra-wide apparent field eyepieces: 68-degrees,
82-degrees, 100-degrees, more. I just love the sensation of looking through a
gigantic spaceship porthole. And there are practical reasons to embrace
ultra-wide fields. More apparent field brings more true field with it. If
you are using an un-driven Dobsonian, a larger true field means less frequent nudge-nudge-nudging
to track objects.
And especially less nudge-nudge-nudging at the medium powers
that are so useful in the backyard. A 12 - 14mm range eyepiece with an 82-degree apparent
field gives you plenty of space, but enough magnification when used in the average telescope
to spread out that yucky background sky glow and increase contrast a bit.
Unfortunately, heretofore ultra-wide fields came at a price,
a price in money that was too high to allow some of us to experience 82-degrees
or 100-degrees of heaven. That’s changed in the last few years with the
introduction of reasonably priced imported ultra-wide angle eyepieces (actually, even
top of the line oculars are imported today).
How good are these budget priced (well sorta) alternatives?
The 82s have been very good for a long while. Some years ago, I tested the Uwans from William Optics and found
them fully competitive with the high priced spread in almost every way. Since
then, Mainland Chinese 82s have become something of a drug on the market, with
very good ones from folks like Meade and Explore Scientific going for as little
as 130 bucks a pop. How good are they?
Very good. Usually at least as good as and sometimes better than the Uwans of yore.
 |
| M64 |
What if you want MORE though? What if you want
100-freaking-degrees of AFOV? I wanted that very thing some years ago, a 100 in
the 16mm focal length neighborhood. But I couldn’t afford the Cadillac, which
was well over 700 dollars at the time. What my modest budget would allow was
one of the first 100-degree eyepieces to come to these shores from Mainland
China. These were sold wearing a variety of badges including Zhumell, Orion,
and TMB. I ordered the Zhumell, not quite sure what I would get, but being
pretty convinced I would not get perfection for less than a third the cost of
the real deal.
And I didn’t, but you know what? The Zhumell 16mm, a.k.a.,
“the Happy Hand Grenade” wasn’t that bad either. Were the stars at the edge of
that great big field perfect? No. There was astigmatism and other aberrations.
However, much of the trouble had to do with me and my telescope and not the
eyepiece.
A major reason for the ugly looking stars out toward the
field edge was the astigmatism in my eyes.
Another was due the coma inherent in an f/5
Newtonian mirror—no eyepiece, no matter how expensive, will fix coma; only a
coma corrector can do that. All in all I was pleased. The big field was nice
and since I don’t waste my time obsessing about the field edge, I thought I got
my money’s worth.
Fast forward to today and things are even sweeter in the
100-degree arena. Meade (see my review of their 100-degree oculars in the
August 2016 Sky & Telescope) and
Explore Scientific are, again, upping the ante. Their reasonably priced 100s
can, frankly, be astonishingly good. I was especially impressed by the ES 20mm.
My friends and I did a shootout
between it and the competition’s 100-degree 21mm a few years ago on the
hallowed observing field of the Chiefland Astronomy Village and were frankly
amazed. Was one better than the other? Hard, very hard, to say.
And there are new players coming onto the field with their
own Chinese 100s: William Optics, SkyWatcher, and others. It’s an interesting
time to be a dollar-conscious amateur astronomer with an eyepiece Jones.
So, should you pay the extra fare for the “best”? That’s for
you to decide, but I’ll no longer be
paying a premium for a relatively small increase in performance. All else
aside, the “quality” of my vision means getting closer to perfection than what I
get with less expensive eyepieces won’t help me much. Your mileage may vary,
but I prefer to give up a mostly unobservable degree of improvement and use the
money I “save” to pay my inevitable weekly bar tab at Heroes.
M64: The Blackeye Galaxy
Yes, the Blackeye Galaxy is spectacular, but it is a subtle
spectacle. It can be detected in amazingly small backyard scopes—its magnitude
of 8.52 coupled with a large but not too large size of 10’43” sees to that—but
small scopes won’t show the dark patch, the black eye, near the galaxy’s nucleus that most
observers long to see.
 |
| The Trio... |
M64, located in the spring constellation Coma Berenices, is
fairly easy to find without electronics, if not as easy as its predecessor on
the list, M63. The best way to approach it is using magnitude 5.0 35 Comae. The
star is almost halfway along a line drawn between Diadem and Gamma Comae, stars
that should show up—if barely—in fairly poor suburban skies. 35 will
likely require optical aid, but a 50mm finder will reveal it easily. When you
have the star in the eyepiece, move 1-degree northeast and you should bump
right into M64.
Your reward for hunting it down? The galaxy is undeniably
impressive in a 4-inch on a nice night. In a medium power eyepiece, it’s a
large oval of nebulosity that really “looks like a galaxy.” A 4-inch will also
reliably show M64 is possessed of a small, near-stellar appearing nucleus.
Alas, that is about it. Occasionally I’ve been convinced I’ve seen a hint of
the black eye, the dust patch near the object’s center, with three and four
inch backyard telescopes, but it’s just an impression I get when I use averted
vision. Not something I can hold steady with direct vision.
Seeing the black eye easily takes at least an 8-inch. In the backyard, a C8 will turn it up, but it’s still not going to be something you can admire
with direct vision. That will take a 10-inch on a good night at 150x and above.
Wanna kick it up a notch? A larger scope under dark skies will begin to show the
black eye isn’t a round black spot at all, but instead a curving arc of dark
material. My C11 shows that fairly reliably at a dark but not crazy dark site.
One year at the Georgia Sky View star party at Indian Springs State Park near
Jackson, the C11 made this galaxy into an absolute thing of wonder.
M65: The Leo Trio
(with M66 and NGC 3628)
Oh, M65 is good. Don’t kid yourself about that. M65 is
slightly dimmer than M64 at an integrated magnitude of 10.25, but it is also
smaller, 8.1’x2.1’, so it stands out well. That said, in the backyard on a
so-so night, it’s more of a smudge that teases you with hints of detail than
anything else.
M65 is easy to find manually thanks to its proximity to one
of Leo’s bright “hindquarters” stars, Chertan, Theta Leonis. With Theta in
the finder, scan two and a half degrees east-southeast and you should run across
M65 without fail. You will also likely notice the similar (though hardly
identical) M66. Which is which? M65 is the eastern galaxy and M66 is the
western one.
While M65 is easy to see with a ten or eleven inch scope in
the backyard—heck, it’s not really a challenge for a four or five—seeing detail is a little dicier. That takes
dark skies and at least a ten-incher for me. Under suburban-country transition
zone skies, there’s still not a wealth of detail to be seen in the galaxy. It’s
a strongly elongated lens shaped object with a bright center. What it looks a
lot like is a miniature Andromeda, M31. Under the best conditions with a
12-inch I get hints of a dust lane near the periphery of the disk, but it is
not easy.
M66
M66 at magnitude 8.92 and 9.0’ across its longest dimension
appears similar in brightness to M65, but strikingly different in appearance.
The most amazing thing for me is how easy it is to tell M66 from M65 visually even under rather poor conditions with a rather small telescope.
If you found M65, you can find M66, so no worries there.
Once you are on the proper galaxy, what will you pull out? In the backyard, the
most prominent thing is this SAB galaxy’s large, bright elongated, central
region. That and a faint outlying haze is about all I get from the back 40,
though. At high quality observing sites, the 10-inch or the C11 will begin to
reveal at least one of M66’s huge, sweeping spiral arms and tantalizing dark details.
The true joy of M65 and M66 is in their “Leo Trio” guise, however. In addition to the two bright galaxies, there’s a third, dimmer one
here, magnitude 9.48 (but looks considerably fainter than the Messiers)
Hamburger Galaxy, NGC 3628. It’s a near edge-on, and when observed from dark
sites with 10-inch and larger scopes it can show a prominent equatorial dust
lane. If you have an eyepiece that can frame about 45’ of sky, you can get all
three of these beauties in one field. Let me tell you, the view in my 10-inch
Dobbie, Zelda, equipped with a 13mm 100-degree eyepiece, which easily frames all three, is stunning.
M67
As you know, I am not the world’s greatest open cluster fan.
But some I do like, like M67, Cancer’s “other” open cluster. It’s rich and it
is different. It’s quite old for a galactic cluster, on the order of up to five
billion years as a look at its color-magnitude diagram shows. Cool thing,
though, is that this magnitude 6.9, 25.0’ cluster looks its age. M67 is a
sprinkling of gently glittering amber gemstones set amidst Cancer’s lonely
stars. Embers fading away at the end of time.
Finding M67 is as easy as falling off the proverbial log
since the cluster lies near Cancer’s Alpha star, Acubens. While Acubens is not
very bright at magnitude 4.25, it’s usually detectable naked eye from the
suburbs when the Crab is riding high. When you are on it (a zero power finder
working in tandem with your 50mm finder scope
helps), just cruise 1-degree 45’ northwest and you will encounter this pretty
group.
When you have M67, the first thing you’ll notice other than
that it’s a nice, very nice, if somewhat subdued cluster, is that it is slightly
elongated, and, more than that, that it is quite rich. A 10-inch under
reasonably dark skies will easily show more than 100 suns here.
M68
M68 is a very sweet little globular star cluster. Unfortunately,
for some of you this Hydra object is a bit far south, declination -26. How far
south is that? Well, about as far south as M83, the Southern Pinwheel. This is
the last stop before you get to the land of Centaurus and Lupus, y’all. If,
however, you’ve got a good view to the south you’ll like this one. It’s
reasonably bright at magnitude 7.3, reasonably large at 11.0’, and loose enough
to be easy to resolve without being so loose that it is dim.
The main problem for mid-northern-latitude observers hunting M68 without computers is
that more than a few of them are unfamiliar
with this far southern part of the sky. Best way to the glob? Probably by using Beta Corvi and Epsilon
Corvi, both of which are bright. The cluster forms a near right triangle with
the two and lies 3-degrees 30’ south of Beta (Kraz).
If, like me, you can get pretty far south before running into
too much of the trash near the horizon, M68 can be a treat, even in a smallish
scopes, as it was one night with my ETX125, Charity Hope Valentine, from the
club dark site:
M68 is a pretty Shapley-Sawyer
class X globular cluster in Hydra. It doesn't look as loose to me as its X
rating would indicate. What I see is a somewhat elongated, very grainy
appearing core. It is not close to culmination yet and is fairly low on the
horizon and in the haze, but I can see quite a few tiny stars winking on and
off around the edges of the central area. Best at 170x.
M69
This globular, another of those that crowd along the base
of Sagittarius’ Teapot (which believe it
or not is now beginning to climb back into the sky at mid-evening), is middling
good for me at magnitude 8.3 and 8’06” in size. And from more southerly
latitudes than my 30-degrees it must be impressive. I doubt it would be a
showpiece even if it were overhead, though. It’s a
middle-of-the-road glob.
At least it is easy to find. Draw a line from Eta Sagittai
through Epsilon, extend that line for another 2-degrees 30’ and you are there.
Take it easy, though. If you are at a fairly high latitude, the glob might not
jump out at you. Check the field carefully using a medium power ultra-wide
eyepiece if possible.
With M69 in view, you are probably going to be pleasantly
surprised at what you find—especially given me dissing the little guy. This
Class V glob is small enough to remain bright, and not so tight as to be
difficult to resolve. 150x in an 8 or 10-inch telescope from a passable site
will just about always do it.
M70
This Sagittarius glob is in many ways similar to M69. Same
class, V, similar size at 8.0’, but a little dimmer at magnitude 9.06 and
slightly farther south. So, the impression I get is “a lot like M69, but not quite
as nice.” It’s a Messier, though, so “not so good” is still awfully good when
compared to your average NGC globular.
If M69 is easy to find, M70 is Real Easy. Just draw an
imaginary line between the Teapot’s base stars, Ascella and Kaus Australis. M70
is almost smack in the middle of the line. As with M69, don’t get too cavalier.
If M70 is low in the sky for you, it may not be obvious in the field at first
glance.
Despite its couple of minuses compared to the previous glob,
the impression I get of M70 is “much the same.” It might be just a touch harder
to resolve than M69 on a comparable night, but not enough to make much
difference. 150x is a good power for me with the 10-inch.
So, what’s up next Sunday? We may take a week off from the Messiers.
I’ve got a new piece of astronomy software here I’d like to tell you about, the
new version of Deep Sky Planner, and it is my intention to do that next time.
Rest assured, though, we will soon be back on the Messier trail.
Comments:
<< Home
This is a really great series. I have enjoyed it as well as your turn towards dobs and refractors.
Two quick questions:
I have been a casual observer since the 90's and use regularly my old c14 and a orion xt8 dob. I rarely use a 120 omni alt refractor that I bought a couple of years ago. I have been amazed at how large and tall a mount it seems to require if I am not to be on my knees or the ground when objects are near the zenith. I end up using my g11--in which case what's the point?(apart for cleanly spaced doubles etc.).
Is there a technique you have found for observing with a 4-5" refractor comfortably without a tall/strong mount?
Secondly, how would you compare your edge 8's views to your 10" dob? I will likely be replacing an 8" Meade (that I deforked from its lx200 mount when inevitably the electronics failed many years ago) that is getting quite banged up since it was new in the mid-90's. Wondering whether a reasonably sized (10" or less) sct is now close to an 8" or 10" newt for Messier objects.
Thanks!!
Two quick questions:
I have been a casual observer since the 90's and use regularly my old c14 and a orion xt8 dob. I rarely use a 120 omni alt refractor that I bought a couple of years ago. I have been amazed at how large and tall a mount it seems to require if I am not to be on my knees or the ground when objects are near the zenith. I end up using my g11--in which case what's the point?(apart for cleanly spaced doubles etc.).
Is there a technique you have found for observing with a 4-5" refractor comfortably without a tall/strong mount?
Secondly, how would you compare your edge 8's views to your 10" dob? I will likely be replacing an 8" Meade (that I deforked from its lx200 mount when inevitably the electronics failed many years ago) that is getting quite banged up since it was new in the mid-90's. Wondering whether a reasonably sized (10" or less) sct is now close to an 8" or 10" newt for Messier objects.
Thanks!!
I really enjoy this series on the Messier objects as well as hearing your transition to back to dobs and refractors.
Two quick questions:
As a casual observer since the nineties (still loving and regularly using my c14, a more recent xt8 dob and a deforked 8" Meade, after the lx200 electronics inevitably died!) I acquired a cheap omni xlt refractor thinking it would be a light quick set up. I found that even though the scope is small and very light that I end up using my g11 head and fairly large tripod so that I don't end up kneeling or on the ground at zenith. No one talks about this; is there a secret to using a lighter mount, without too much shaking and still not ending up on on near the ground?
Second, how would you compare your edge 8" to your dob in terms of views. I probably will be replacing my (no banged up) 8" from the mid-1990s and am curious about the current views from a good set 8" vs dob.
Thanks!!!
Two quick questions:
As a casual observer since the nineties (still loving and regularly using my c14, a more recent xt8 dob and a deforked 8" Meade, after the lx200 electronics inevitably died!) I acquired a cheap omni xlt refractor thinking it would be a light quick set up. I found that even though the scope is small and very light that I end up using my g11 head and fairly large tripod so that I don't end up kneeling or on the ground at zenith. No one talks about this; is there a secret to using a lighter mount, without too much shaking and still not ending up on on near the ground?
Second, how would you compare your edge 8" to your dob in terms of views. I probably will be replacing my (no banged up) 8" from the mid-1990s and am curious about the current views from a good set 8" vs dob.
Thanks!!!
# posted by 
: 1:18 PM
: 1:18 PM
Sorry for the repeat posts. I hadn't seen my comment on the blog so I though something was wrong--just understood the warning on comment approval.
Post a Comment
# posted by : 1:20 PM
: 1:20 PM << Home
