Regular readers know that I spent three clear nights with a telescope at Hacienda Los Andes last weekend. Below, I will describe some of my observations from the weekend. If you’re not an amateur astronomer or really curious about the activities of amateur astronomy, this post may be long. It is an attempt to both relate the observations I made with the scope and give an idea of why and how I do such things. If you get fed up, you can skip to the end where the pictures are. As you scroll through, you’ll see a picture of some of my sketches. That is probably worth stopping for. For a laugh if nothing else.
An earlier point of view: Passion, work and fatigue
I’ve seen the southern sky before. My first good look at the Southern Cross (constellation Crux) and Alpha and Beta Centauri were from a tent on Haleakala in May 2000. I arose in the wee hours of the morning to, well, do what the name of the hours implies, and, as I stood there outside the tent, were the cross and our nearest star. Of course, the cross looks more like a kite and Alpha Centauri looks like a very bright star (it’s the third brightest in our sky). But I was still awed. Mary was a good sport about my waking her up to see them.
My next glimpse of the southern sky was in May 2006 in Salvador, Brazil. I was at a conference, staying in a nice place on the beach. It wasn’t a nice beach and the hotel staff really didn’t want me walking out there alone at night but it was clear and I’d brought binoculars and I felt confident (read: naive) that I could handle myself. As it happened, no one bothered me and I had a fine time picking out open clusters with my binoculars.
There are two types of clusters: open and globular. Open clusters are usually a group of hundreds or a few thousand young stars born from the same ball of gas that will, eventually, disperse. A globular cluster is a tight group of hundreds of thousands or millions of stars that have hung together for a long time. One theory is that they’re galaxy cores stripped of the gas and extraneous stars one normally finds in galaxies.
In May 2011, I was back in South America at another conference in Mendoza, Argentina. This time I did some advance work and hooked up with a guy named Leo online. After the conference, I met up with him and his observing buddies and headed for a park far to the north of Mendoza, in the foothills of the Andes. It occurred to me that meeting a guy online and driving off in the boonies with him is a a good start to a horror film. Once there we observed with his 8 inch reflector and I was introduced to mate and the idea that folks who share a passion can overcome a lack of a common language or, indeed, common anything. It remains to this day one of the finest experiences of my life.
Which brings us to this year. If you’ve followed the blog, you have read about my trip south of Buenos Aires at an airbnb where I spent two clear nights looking at the southern sky on my own. The first weekend in Chile, I spent at Los Nogales Roan-Jase, a fine astronomy inn less than an hour from Santiago. I had a great Saturday night there with my home built Dob and imaging platform.
Wait, I hear you thinking, this was supposed to be an observing report from Hacienda Los Andes. Yeah? And? Get your own blog.
The Hacienda was my first actual planned observation of the trip. I had hoped to squeeze in some sky time before now but wasn’t sure. It’s a job, after all. I got lucky and spent more time under clear skies than I had any reason to expect. But I knew before I left that I had this past weekend free and had booked the Hacienda many months ago. If, after reading the rest of this, you want to book the Hacienda for a New Moon weekend, you should do so at least 3 months in advance.
It seems strange to non-astronomers but we astronomers don’t, generally, want the moon in the sky. Of course, there are many observers who love the moon and want to observe it and there isn’t another object in the sky that shows as much change or detail as the moon. On the other hand, there isn’t another object in the sky that we’ve walked on before, either. In any case, the moon is very , very bright. Its light, especially at Full Moon, tends to wash out fainter objects we like to look at. So, New Moon is a great time to see the universe.
I flew to La Serena and then drove to the Hacienda. I’ve described this elsewhere. In point of fact, it’s equally fast – and more practical – to rent a car in Santiago and make the drive. The hacienda is about 6 miles west of a little town called Hurtado. Both the town and the hacienda sit on the banks of the Rio Hurtado. The observing field, which sits on a hill above the hacienda proper, is at an elevation of 1,066 meters. Lovers of English history will be able to keep that one in mind. I rented the 12.5″ f/5 Portaball with a Zambuto mirror. It was set on a cement pad on a hill overlooking the Hacienda. The pad had outlets for AC power which let me run a computer to control imaging. Some of the other guests had as many as 4 imaging rigs running on their pads.
It’s very dark at the Hacienda. As dark as the skies in the southwest of the United States. I once spent two weeks observing from Natural Bridges National Monument in Utah which was darker. There was a bit of a light dome in the northwest from La Serena and a few local lights. Every now and again a car’s headlights would hit just right and illuminate our hill.
The sky from a truly dark site is incredible. I will go out on a limb and say that most of you have not seen this. You may think you have because you got a few miles from town. But if you live east of the Mississippi in the United States, or anywhere in Europe, you haven’t seen a truly dark sky. We have really buggered the night sky with lights. I get it, we need to be able to see in our driveway. But, look, you should have a light on a switch. When you’re not trying to find your wallet in the footwell of your car, you can have the light off. Light isn’t keeping people from breaking into your house. No one is looking at your house. Burglars could have a five course meal in the bushes outside your front door and no one in an American neighborhood would notice. Light only lets them see their way to your soft spot. Similarly, businesses and used car lots do not need to advertise to people living on the Moon.
At some point, find a really dark place and wait for a clear, moonless night, and go have a look. It’ll change your life.
Last weekend was several such nights in succession. I have seen a lot of dark nights from the northern hemisphere and, without too much modesty, I can say that I know the northern sky very, very well. Despite several nights looking at the southern sky, I’m still a little lost down here. So, sitting with the rented scope, having my imaging rig aligned and ready, I watched the sky darken and totally forgot everything about my life. Well, not everything. I could recall my name and I would have been able pick Mary out of a lineup. But it was an incredible experience. At nightfall in March, Crux is about halfway up the sky in the southeast. Orion is heading for bed in the west. Vela is nearing the zenith. The Milky Way stands out distinctly. I turned the Portaball first to the Large Magellanic Cloud which was about halfway from its highest point to lowest (it does not set from the latitude of the hacienda). At 160x, the Tarantula Nebula is a looping mass of gas that pushes waves of light through the field of view. If you’re an observer and you like nebulae, you owe it to yourself to see the Tarantula through a decently large scope. Neither it nor Eta Carinae are as bright as M42 but they provide much more detail. Given that the Tarantula is actually in another galaxy, it’s even more impressive.
Speaking of Eta Carinae, it’s an amazing complex of nebulosity. No part is super bright but the brightness stays pretty even throughout a degree wide field. It’s enormous. And then there is the dark, dusty nebulae superimposed on the emission nebula. You’ll be tempted to keep the magnification very low. Don’t! The Homunculus nebula around Eta Carinae itself is easily visible at high power and shows definitive color.
Most objects outside the solar system are too dim to show color in the eyepiece. Our eyes perceive color using the center of the eye which is populated by cone cells. But the center of your eye, used during daylight, is what shows color. However, the cones are less sensitive to light and, so, when the light dims, your eyes dilate and the rod cells on the periphery of your eye takes over. These are much more sensitive to light but do not give color. This is why most things look colorless at night. With night vision, everything is greenish-grey. Using this mode of vision well is a large part of learning to be a skilled telescopic observer. The rods also have poor spatial resolution so seeing detail in low light situations is difficult.
Nebulae is the word for “clouds” in space. Some are clouds of hydrogen which are stimulated to emit by stars in their midst which emit ultraviolet light. Others simply reflect starlight. Still others are mostly dust and neither reflect nor emit. These are called “dark nebulae”. They appear as voids in the eyepiece or photographs.
The Homunculus Nebula (google it) around Eta Carinae is plainly visible at 160x and striking at 340x. And it’s orange. Very, very orange. This freaked me out a little. The Eta Carinae nebula (pictured a few times below) is far too large and complex for me to attempt to sketch. However, the star Eta itself is a bright orange-red that pops out at you. As I said above, there generally isn’t a lot of color in the eyepiece. Stars are the exception as the brighter ones are sufficiently bright that we can see color. Eta is certainly in that class. In 1837, Eta underwent a “great eruption” – a brightening – to be the second brightest star in the sky for a few weeks until it faded below naked-eye visibility. It has behaved eccentrically since and there is a good chance that in an astronomically short period of time it will appear in our sky as a spectacular supernova. Don’t wait up. Astronomically short could be a million years easy.
During the Great Eruption, Eta belched out tremendous quantities of gas and dust and that is what we see today as the Homunculus Nebula. It’s small – less than the apparent size of Saturn’s disk – and bright and so we can see some color. This came as a complete surprise to me as I didn’t even know we could see the nebula. In the eyepiece, the Homunculus nebula is very, very orange. (Color is always a matter of some subjectivity; others claim it is orange-pink or orange-red or just red. It depends on the observer and gear used. Much like internet dresses.)
I like to sketch. I’m lousy at sketching. But the act of trying to draw an object at the limit of visibility makes you tease out detail you wouldn’t otherwise. Sketching was, at one point, the only way to record an observation so astronomers needed to either be very good at this or hire someone who was. Today, most of us who do this are trying to increase the amount we can see. There is something about the brain/hand relationship that drawing or writing increases perception of details. Anyway, here are some sketches:
“Redo” means I redrew the object from a sketch at the eyepiece and notes. Sometimes I do this a couple of times. Starting at top left is NGC 3576, an emission nebula in Carina. There were some very bright clumps but lots of faint, subtle detail. A second emission nebula, NGC 3603 with an associated open cluster is visible in the same field of view but was fairly featureless. These are both within a few degrees of Eta Carinae and equidistant to the Lambda Centauri cluster and its nebulosity. I don’t know but my hunch would be that they’re all bright spots of a larger collection of gas.
The Tarantula sketch is to the right of NGC 3576. No sketch could do it justice. It’s both very bright and has lots of fainter wispy bits. Below 3576 is my rendition of the Homunculus.
Below the Homunculus are two small planetary nebulae. NGC 3132 is called the “Eight-Burst nebula” for obvious reasons. The two intertwined rings (a trick of perspective) are clearly visible when the seeing settles at 160x. At 340x there is some detail inside the rings but it was just at the edge of my vision and I couldn’t quite nail it down. NGC 5189 is an odd shaped planetary. Most are round in some fashion. This one looks a bit like a small tornado and the bright leading edge has a twisted look to it. There are brighter clumps interspersed with fainter clumps and a fairly bright tail curving around a star of 11th magnitude or so.
A planetary nebula has nothing whatsoever to do with planets (well, their formation probably results in the destruction of a few but other than that). The brightest ones looked, in olden telescopes, similar to faint planets. Indeed, Uranus and Neptune do fine planetary nebula impressons. But with better scopes the resemblance fails. Planetary nebula form when an old star that isn’t big enough to go supernova puffs out a massive shell of gas. It may do this several times as it ages, being not unlike older humans in that regard. This gas expands and is stimulated to emit light by absorption of the dying star’s light. Often, the shell expands spherically but other times stellar wind and/or magnetic fields warp the gas into fantastic shapes as in the case of NGC 3132 and NGC 5189.
Two other notes: NGC means “New General Catalog” which is now a couple of centuries old. Magnitude is a unit of measure for stellar brightness and is logarithmic in a complex way. Stars with lower number magnitudes are brighter. So, a magnitude 1.0 star is 2.5 times brighter than a magnitude 2.0 star. Five magnitudes is roughly a difference in brightness of one million fold. The dimmest star you are likely to be able to see with healthy, dark-adapted eyes from a truly dark site under good conditions is between magnitude 6 and 7. From my driveway in Winston-Salem, I’m lucky if can see 3rd magnitude stars. Here in Santiago, I can pick out the Cross and Alpha and Beta Centauri, all stars of the 1st magnitude.
The remainder of the objects on the page above are galaxies outside the Milky Way. NGC 5128, pictured below, is also known as Centaurus A because it puts out tremendous amounts of X-rays. Some very energetic things are happening at its core. It sports a very fat dust lane with some detail within. The lane is surrounded by two evenly lit hemispheres. One hemisphere is brighter than the other and one edge of the complex is sharply defined while the other sort of trails off. I’m dissatisfied with my sketch. Too much going on in the dust lane and the halo around the hemispheres, while visible in the eyepiece, is not nearly as bright as the sketch indicates. However, I don’t have the hand to render a gentler drawing.
NGC 4038 and 4039 are interacting galaxies in the constellation Corvus. I’ve seen these many times from home but here they near the zenith (highest point in the sky) where they should be more easily visible. Indeed, they were easy to find and showed decent detail including the bridge between the two. Again, my sketch fails. I have here the opposite problem than with 5128. They are a good bit brighter than indicated with the larger (4039) being noticeably brighter than the smaller. Every time I try to rectify the situation I make them equally bright. I will doodle more.
M83 is another galaxy I’ve seen a lot from home. You’ve seen pictures of this one. It’s a classic face-on spiral galaxy. That is, we are looking down from above it (or up from below it, however you wish to view the universe). With spiral galaxies, that gives us a chance to see their arms. However, usually the galaxy is too dim to show that kind of detail. In addition to not giving us color, the rods do not have good resolution. So, if you’re using the rods to see an object, you are unlikely to resolve subtle details. Again, this is one of the skills an observer needs to learn to fully enjoy using a telescope. I had always read that M83 should show its arms similarly to M51, the Whirlpool Galaxy. But at home M83 is always too low to show up bright or in steady enough air to see detail. It’s always just been a featureless blob. Not so from the Hacienda. I was able to pick out several arms and suggestions of smaller shoots off those arms and the core.
Finally, I show NGC 4995, a spiral galaxy we see edge-on so that it looks a bit like a lens. In this case, the lens is having a gas and dust issue on one of it’s flanks which was plainly apparent in the eyepiece. I knew nothing about it but was guided to the galaxy by my friend Leo’s Southern Sky handbook. I like to look at an object for the first time before reading a description so as not to see things with my imagination. I was gratified to read that the galaxy does indeed have a quarter that is mostly obscured by dust. This may be my favorite (that is I think it most accurate) sketch of the set.
I observed many, many objects I didn’t sketch. I have a lot of trouble sketching star clusters and there are approximately 11 gillion of them in the southern fall sky. The Jewel Box was the showpiece as it is both rich in number and varied in color. With the fine optics in the scope, the stars did indeed seem to be jewels on a black silk field. In addition to the Jewel Box, I have checks by 17 open clusters that I both saw and identified. There were more but I had gotten lost and couldn’t positively identify them. I also have checks next to 14 globular clusters which are my favorite type of object. Omega Centauri (pictured below) is a clear favorite but there were several that were the equal of M13 at home. NGC 2808 was a particular favorite. Additionally, there were 9 other galaxies and 4 other planetary nebula.
I was also able to find and detect the Vela supernova remnant. When a star goes supernova it blows much of its mass out into space. This includes every element heavier than iron which are only formed during a supernova. The outburst is violent enough that over time, the gas density falls to the point where it can be tough to see. This one is very narrow, looking like needles in the field of view. I could really only hold them with averted vision (the art of not looking straight at the object so as to let the light fall on the eye’s rods).
Backing away from the scope as Scorpius rises in the southeast, it’s possible to take in a lot of brilliant Milky Way and many bright stars. I’m slowly learning my way around the constellations. By April New Moon, when I’ll be out again, the center of the Milky Way will be up before dawn. At the end of June, when I hope to get back to the Hacienda, the center of our galaxy will be near the zenith. I’m sure I’ll have more late night poeticals at that point.
While I was at the eyepiece, I let the computer run the camera and came up with a few good shots including some for objects described above. The little tracking mount I have is not capable of carrying a telescope or to track with a long focal length lens for long periods of time. So, while I described looking at tiny objects at high power above, the pictures are of wider fields. I used an 18mm lens, a 50mm lens and a 200mm lens.
If you skipped the observations, here is where you should come back in.
The Milky Way running through the constellations, from left to right, Carina, Crux and Centaurus. The Eta Carine nebula is about halfway from the center of the image to the left edge and halfway between top and bottom. Crux is “upside down” just below and to the left of the Coalsack, a dark nebula that obscures our view of the Milky Way stars behind it. The Coalsack is the dark patch basically dead center of the image. Alpha and Beta Centauri are in a line running from the Coalsack through the dark band on the right edge. Alpha is the more orange of the two and, in this image, the one closer to the top.
This image was made with a 200mm lens which is not nearly enough for the two objects. On the right is Omega Centauri, the biggest, brightest, most impressive globular cluster in the sky. On the left is NGC 5128 which is described and sketched above.
Crop of NGC 5128 from the image above. The dust lane is clear as is some detail in the dust lane. It’s also clear that my stars are not pinpoint even with a short 45s exposure. Nuts.
This is both cropped to Omega Centauri and processed differently to better show the very bright cluster. The camera sees much, much more than we do. However, we have a huge advantage in dynamic range. We can look at a bright thing and a faint thing and see detail in both. A camera basically needs to choose one to highlight. Cameras would have been eaten by tigers by the campfire long ago.
The Eta Carinae nebula with a 50mm lens. Eta is at center. The Lambda Centauri cluster with associated nebulosity is just to right of center at the very bottom. NGC 3576 and NGC 3603 are two faintish, small bits of pink just to the right of a dark nebula about halfway between Eta Carinae and Lambda Centauri.
The Large Magellanic Cloud with a 50mm lens.
Antares (the orange star), M4 (the globular cluster above Antares) and the Rho Ophiuchi molecular cloud with a 200mm lens.
The Large Magellanic Cloud with a 200mm lens. The Tarantula Nebula is to the right of center almost at the very top. The 200mm lens is a bit too much for this one and it doesn’t help that I didn’t get it arranged correctly.
The Eta Carina nebula with the 200mm lens.
The Milky Way from Orion (above center on the very left) to Lupus. Crux and the Coalsack are on the center to the right. This is a mosaic of 4 images shot with the 18mm lens.
If you’re interested in seeing these at higher resolution you can find them here: