Sunday, October 09, 2016
Issue #512: More Messier Madness!
|M87 shows off its jet to my Stellacam...|
What better time is there for chasing Ms? The nights are cooler now and their skies are clearer (you hope). Down here, I may only have to douse myself with one gallon of Deep Woods Off instead of two. And, oh! the Messier beauties you’ll find lurking now. The mid-late summer objects are still on display and lookin’ good. A glance to the east, though, will show the Autumn wonders are on the rise—look how high M15 has gotten—and if you’re up late you’ll begin to witness glories of Winter climbing as well.
Yes, fall’s a great time for a Messier hunt, for crossing them off your Life List. For this week’s edition, however, we’re taking the WABAC machine back to spring as we navigate through the countless faint fuzzies that comprise the great Coma-Virgo cloud of galaxies.
Yes, Coma – Virgo is wonderful, but what makes it wonderful? The sheer number of galaxies on display here and their pairings and groupings. When you stop to think about it, many, many are ellipticals without much detail to offer. Tons of ‘em are certainly easy enough to see with a medium size telescope in the backyard, however, including Messier 85, a magnitude 10.0, 7.6’ x 5.9 S0 elliptical galaxy. And you get a bonus galaxy to up the interest level; M85 is in the field with a dimmer companion, magnitude 11.6. 3.6’ x 3.5’ NGC 4394.
To find M85? While goto or DSCs are the way I’d go in these latter days, M85 is not too hard to pin down. It lies about 1.5-degrees outside to the northeast of a line drawn between two prominent stars, Diadem, Alpha Comae, and Leo’s Denebola. A magnitude 5 range double star, 11 Comae, is just a smidge over a degree to the west of the galaxy.
In the backyard, you’ll want at least an 8-incher to make this object easy on the less good nights. M85 is a galaxy that can be bright in small apertures on good evenings, but dim to the point of toughness on poorer ones. Above all, despite the fact that this is a lenticular with an oval, elongated shape, expect to see nothing more than the good old “round galaxy with a brighter center.” In other words, much like an unresolved globular star cluster. In order to see elongation in M85, I normally require 12-inches of aperture and a halfway decent dark(er) site.
How about the companion, NGC 4394? While it is small, it’s not tiny and is approaching magnitude 12. The 10-inch Dobsonian, Zelda, will show it on a nice night, albeit sometimes with difficulty. It is about 8.0’ northeast of the main galaxy. Medium high magnification can be a help here. In the backyard, what you can expect to see if you can see NGC 4394 is a relatively faint, round glow. From dark sites with larger apertures, this barred spiral galaxy begins to reveal its arms.
|The Face lookin' atcha...|
M86, an elliptical galaxy in nearby Virgo, as I mentioned in the last installment, together with its companion galaxy, M84, never fails to elicit a chuckle from me. This grouping is “The Face.” M84 and M86 form the eyes, a little elliptical galaxy, NGC 4387, is the nose, and a near edge-on galaxy, NGC 4406, is the mouth. At magnitude 9.8 and with a size of 10.0’ x 7.4’, M86 is quite prominent in 8-inch and larger scopes even from a relatively compromised backyard.
As I said in the last M-edition concerning M84, “There are so many bright galaxies within the arms of Virgo that it’s hard to know which one you are on. Luckily, the field here is pretty distinctive. If you simply must find 84 the old fashioned way, it lies halfway along a line drawn between Epsilon Virginis, Vendemiatrix, and Denebola, Beta Leonis. Positoned there, look for two bright fuzzballs about 17.0’ apart.” Which one is M86? It is the northeastern-most of the two brightest objects in the field. It is also more elongated than M84, being a Hubble Type E3.
As above, the cartoonish Face is the attraction here, that and the fact that this is the western terminus of Markarian’s chain, the mind-blowing line of galaxies stretching off to the east. But M86 itself? Sorry, pards; it is just another bright elliptical. Very noticeable but very featureless.
And so on to Virgo’s monstrous old fat-daddy spider of a galaxy, M87, for more of the same. This is one of those “been there” objects: there’s not much to see; all you can say is you’ve been there. Actually, there’s a little more to it than that. The knowledge that this is an awesome giant of a galaxy, a titantic elliptical with a mass of a trillion Sols, makes its sight thought provoking and even moving though there is no detail to be found.
The best way to get M87 in your eyepiece is to get on the distinctive M84/M86 pair first. Then, slew your scope a degree and a half southeast. Go slowly and examine the field carefully, but despite the galaxy crowded nature of this part of Virgo, M87 stands out well. In an 8-inch in the backyard it will be fairly hard to miss, and should be duck soup for 10s and 12s.
No, there’s not much to see of M87 other than a bright fuzzy ball. The field? Not too much here either for a small scope from the suburbs. There are two magnitude 12 range galaxies, NGCs 4476 and 4478, about 10.0’ to the northeast, but while they are small, they really need a 10-inch to bring them out of a bright sky background. In my C11 from the OK but not perfect skies of the old Georgia Sky View Star Party at Indian Springs State Park, M87 was…
Basically a diffuse round glow like a bright, unresolved globular cluster in a 3-inch telescope. With TeleVue Nagler Type 2 12mm, 233x I occasionally see hints of a condensed core, but it's mostly a featureless ball.
So that’s it? How about THE JET? M87 is possessed of a supermassive black hole at its core, and this is the source of an incredible jet of matter spewing out of the center of the galaxy. This jet is so huge and luminous that it can even be seen with amateur telescopes. Alas, those amateur telescopes need to be at least in the 20-inch range and stationed under dark skies. Ironically, my humble Stellacam II deep sky video camera in my C8 had no problem showing the jet with a 10-second exposure under suburban conditions.
M88…M88…which one is that? Oh, yeah, back over in Coma Berenices. It’s a bright enough Sb with an intermediate inclination to us that reminds me a lot of M63 (in photographs) with patchy spiral arms similar to those of the Sunflower Galaxy. At magnitude 10.1 and with a size of 6’54” x 3’42, it is not terribly challenging for a 4-inch when your backyard conditions are anything better than putrid.
The best way to land on M88 is to follow Markarian’s Chain, that great river of galaxies, from its beginning at M84 and M86 for about two degrees to the northeast to its conclusion. Luckily for us, M88 lies right at its northeastern end and is the most prominent galaxy in the immediate area. Take your time and move slowly; this is indeed the Realm of the Galaxies, and in a 10-inch or 12-inch, even from the suburbs, there are island universes all over the place. This is a rather star poor area, but there is a 7th magnitude sun half a degree to the northwest of the galaxy, which provides a good guide to M88.
When you are convinced you have M88, give it a nice long look, sure, but don’t expect too terribly much. Even larger apertures from good site only reveal that it is strongly elongated with a brighter center. The dusty spiral arms are really for the eye of a camera.
So you want to see M89, do you? Well, I salute you for charging through the fuzzy laden waters of Virgo. And this is not a bad one. It’s another round elliptical like many of the galaxies here, but is bright enough at magnitude 9.75 and small enough at 5’06” x 4’42” that it is a reasonably easy catch for your backyard 4-inch. If you can find it. Or, more properly, figure out exactly which fuzzball in the eyepiece is it.
Not sure exactly what to tell you if you have to star-hop. This object is just outside the heart of the Virgo cloud, and there are really no guide stars to help you on your way. If you’re star-hopping with a finder, the best way to go is to move your scope 1-degree northwest of M58, which is substantially easier to locate.
The best way to position the telescope on M89, though? The way I used to navigate Virgo-Coma in the days before computers: I’d galaxy hop. Using a 12mm Nagler eyepiece in my 12-inch telescope, I found it remarkably easy to move around the area by hopping from galaxy to galaxy with the widefield eyepiece and a (very) detailed computer chart. Back then, I used Megastar. Today, you’ll probably want to use SkyTools 3’s Interactive Atlas.
When you’ve arrived, you’ll find that while it is almost featureless, M89 is not entirely so. According to its specs, M89 is slightly oval, but in the eyepiece it looks entirely round. Otherwise it has a fainter halo and a brighter center. However, on an OK night with at least an 8-inch, you may see that it has an intensely bright, star-like nucleus, and that brings M89 into the realm of “very attractive.”
In images, M90, a magnitude 10.10, 9.5’ x 4.5’ spiral, is very pretty indeed, with a bright, oval central region and prominent dust lanes outlining tightly wrapped spiral arms. Unfortunately, once you get outside the central part of the galaxy, its surface brightness is low, and the arms are mostly for imagers, though they can be glimpsed with 10 – 12-inch telescopes on outstanding nights at outstanding sites.
Locating M90 is quite easy if you are already on M89. Just eyepiece hop, following a chain of 10th magnitude stars north for 40’ and you are there. An 8th magnitude star is 14.0’ southeast of the galaxy if you need more help, or just want to be sure you are on the correct galaxy.
When you are on M90, most of the time all you will find is the object’s strongly elongated middle part. And it may not be quite as bright looking as you expect given the galaxy’s fairly generous size. This is a galaxy to keep coming back to on superior evenings, however, since under the best conditions it can begin to give up respectable detail to medium sized instruments.
Oh, how wonderful M91 looks--in pictures. Even in fairly short exposures, this magnitude 10.9, 5.4’ x 4.6’ shows off a classically beautiful barred spiral shape with far-flung, open arms. In the eyepiece the story, as it often is, is somewhat different, but this is still a Messier, after all, and worthy of your attention for sure.
If you wanna get to M91, my advice (for the computer deprived) is to continue your eyepiece hopping, moving 1-degree 22’ west – northwest from M90. Take it easy, since this one definitely looks a little on the dim side. There is a magnitude 8.8 star just 17.0’ west of the galaxy.
I hate to be a bring-down, but even with fairly large telescopes under quite dark skies, about all you will see of M91 is an elongated something, and you may need averted vision to see even that much. On particulalry nice evenings, you may pick up a stellar nucleus. On the other hand, the camera loves M91, and even a 10-second exposure with my Stellacam 2 showed its basic shape:
As befits its status as M91, this is a marvelous galaxy, big, with a bright round core, a long bar, and easy to see, graceful arms that give it a classic barred spiral "S" shape.
And that, as they say, is that. Fun is fun, but done is done.
But we are not quite done with the Messiers here, though we are in the homestretch now, no denying it. How about your own observing program? If you haven’t caught ‘em all, resolve to do that over the coming year. I am hearing from quite a few of you who intend to do that very thing, and some who even say (my blushes) they are going to print out this series of blog entries and use them as their guide. That’s flattering, certainly, and though I don’t doubt there may be better guides to the M-objects than these articles, one thing is sure: the price is right!