I teased about more astronomy stuff in an earlier post. You see, when I wrote up my trip to Hacienda Los Andes here I thought that that was it for my astronomy adventures in South America. I’ve made the mistake of thinking something I was doing here I was doing for the last time several times now. On the astronomy front, the entire nation, save the far north, was battered by a pretty fierce winter storm starting a day before my trip to Hacienda. Last Tuesday, the sky cleared suddenly, with the clouds blowing out about 2pm. As has happened numerous times, I thought to myself, “if only I had my car, I could get out of the city with the scope.”
Only this time, I realized I had a car. I wasn’t set to return the rental until Wednesday morning, having wanted a cushion on the back end of my Hacienda trip in case I needed it. In fact, things were set up so perfectly that I hadn’t yet even taken the telescope upstairs. It was a simple matter of throwing some clothes in the back and heading out. I was at Los Nogales Roan-Jase by 5pm and had negotiated to pay for a camping spot and to leave around midnight.
Roan-Jase is the place I went to observe on my first weekend in Chile after Buenos Aires. I first stayed there last May (2016) on a “scouting” trip and had sort of imagined I’d go there often. Though it’s only 30 miles away, it’s usually a 90 minute drive. That’s traffic for you. Unfortunately, most of the times I’ve been free to go out there, it has been cloudy. Santiago in winter is not a terribly sunny place.
You may be thinking, “30 miles isn’t far enough to escape the light pollution of a city like Santiago.” And you’d be right. Roan-Jase has a significant light dome in the northeast. But it has a couple of advantages that make it better than you’d think. First, the air in Chile is, usually, pretty dry, which suppresses the effect of light pollution. Second, Roan-Jase is up El Cajon del Maipo, so there is a lot of high rock between the site and Santiago. To be sure, it isn’t a dark site but it is actually better than the place I usually go about an equal distance from Winston-Salem.
If you’re wondering how that can be, it’s because rural United States is much more brightly lit than rural Chile. As I’ve written before, through a combination of economics, lower rural population and the realization that it is stupid to light up places where no one is, the countryside in Chile and Argentina is much darker than back home. My club observing site in the United States is not close to a city like Santiago but there is, essentially, nothing to block the light between it and the smaller city it is close to. Also between the site and the city are miles and miles of lights and numerous small towns lit very brightly. Small towns here don’t seem to have that problem. The only real negative rural Chile has for observing relative to rural United States is that almost all rural homes here are heated by burning wood and smoke can accumulate. I didn’t have that problem in March and it made a noticeable difference in the quality of the sky relative to June.
On Tuesday night, unfortunately, the first factor wasn’t true, either. With the front having just cleared out, it was incredibly humid. This increased light pollution, reduced transparency had drenched all my gear with dew. The dew prevented any imaging but I ended up having a really good observing run anyway and cleared a number of objects from southern Scorpius and the constellation Ara, just south of the scorpion. I also had a final look at some showpieces and ended my southern observations with NGC 6520, a cute little open cluster sitting on the edge of the dark nebula Barnard 86 (click on the link for a picture). It’s long been a favorite but it usually gets no more than 25 or so degrees above the horizon back home. When I caught it Tuesday night, it was about 85 degrees overhead. I’ve explained before, but the closer an object is to the zenith, straight overhead, the less air you’re looking through and the brighter, clearer the object looks. It was a good way to go out.
The weather last week was simply fantastic. Highs in the 70s, lows in the 50s, dry, sunny, clear, and beautiful. I noticed that the forecast was the same for Friday and Saturday night. I found a deal on a weekend rental (more on this in a separate post) and the next thing I knew I was ensconced in a cabana at Roan-Jase just before sunset on Friday. It proved a much better night than Tuesday save for the first quarter moon which was surprisingly bright. I actually lay down for an hour and a half to let it sink a bit. Then I was up until 0530 taking in a number of new objects and finishing a couple of imaging goals (see below) I had.
One big reason I wanted to stay up so late was to complete my tour of the south. When I first went out under the southern sky in February, the Small Magellanic Cloud (SMC), the lesser of the two biggest satellite galaxies of the Milky Way, was well past the meridian (its highest point) and by the time I could put a scope on it in March, it was quite low. At dawn in June, it is at its highest point. Moreover, the 70 or 80 degrees west (“ahead”) of the SMC, I had not seen at all. By staying up so late, I was able to take a look at, for me, a completely new part of the sky. It is my last new sky. I can now say I’ve seen the entire universe.
Okay, that’s a small thing. But I was happy to cross it off the list.
Waking up at 10am, I knew I was done. I had planned to either spend another night at Roan-Jase or visit the Santiago club I joined but never was able to observe with. They have club observations at their site in the mountains every Saturday and every Saturday I was in town was either cloudy, full moon or I was out somewhere else in Chile. So…a bit of a waste of money joining but the one cloudy night I spent out there they proved a fine and hospitable group of astronomers and they have a really nice setup in the El Arroyan. But on Saturday morning, I knew I had nothing left in the tank. I had had two late nights in an otherwise very busy week and, sadly, I’m to a point where that is about all I can do. Ask Mary, I was a wee touch incoherent when we talked by phone.
If you’re at all curious, my last telescopic object in the south was 47 Tucanae, which you can see below. It’s an incredible globular cluster sitting just off the SMC. Like most celestial alignments, it is pure chance. One of them is much nearer than the other. Also like many chance alignments, it works out that your eyes lie. The bigger, brighter object in this case is much further away. The globular cluster is about 15,000 light-years away while the SMC is about 200,000. The image below is the one I wanted to stay up for. Sadly, I ran into technical issues which limited how many sub-exposures I could record. A connector had come loose and was slowly slipping on my photo-rig. Since the whole point of the photo-rig is to counteract the rotation of the earth to keep the stars in the same place on the camera chip, a loose connection is pretty serious and in most of the images I snapped, the stars are little bumpy trails belying the slip. At 0500 in the dark I was not equal to diagnosing the problem so here is what we have. If it had been light, or hours earlier, I’d have probably caught it because it was immediately apparent when I looked at it the following morning. Ah, well.
The SMC is the big blue thing taking up most of the right side of the image. 47 Tuc is the ball of stars in the upper left.
Globular clusters have long been a favorite of mine and I knew, deep down, that the finest glob in the sky was Omega Centauri which barely peeks above the horizon in North Carolina. What had I no idea is that second best is clearly 47 Tuc, which you can never see from North Carolina. Nuts.
The next imaging target was one I had “discovered” while here. Okay, clearly I didn’t actually discover a new nebula. I would have reported that a bit more officially. However, I was unaware of this nebula’s existence until I recorded it on a widefield image from the Atacama desert. The nebula is part of a really busy bit of sky near Zeta Scorpii. I can see this region from home but it never rises more than 15 degrees above the horizon, which is low enough to dim the luster of the several star clusters and completely render the nebula invisible. I had hoped to image the region with my 200mm lens from the Hacienda but was foiled by clouds. On Tuesday, dew blocked me. On this Friday, though, it all came together.
Zeta Sco is the bright triangle of stars on the left. The very fine open cluster NGC 6231 is to its lower right. Following to the right is the open cluster Collinder 316 and then Trumpler 24. On the right edge of Tr 24, pretty much dead center, is the nebula IC 4628 (the red cloud). To the lower right of the nebula is the open cluster NGC 6242. The nebula is surprisingly bright, easily visible with an Oxygen-III filter and my 8-inch scope. From the Atacama it was visible without the filter. Fun little nebula. Also note several dark nebulae peppering the field.
I also completed two other imaging missions though they were lower priority for me than the two above. The first is the open cluster M7, a wonderful sight through the widefield of my 8-inch scope and an easy clump of haze with the naked eye. However, I wasn’t real happy with the appearance in the image so I quickly moved on to the next target which was M8 and M20, better known as the Lagoon and Trifid nebulae. These, too, were amazing sights in the scope and have long been favorites of mine (not that that makes me unique – everyone loves these) and it was a treat to see them at the zenith.
Open cluster M7, just to the lower right of center. The globular cluster NGC 6341 is just above a star to the left. Together, they look like two stars. Again, note the dark nebulae as we look toward the center of the galaxy.
The Lagoon (larger, closer to center) and Trifid (smaller, lower right) nebulae. Open cluster M21 is to the upper right of the Trifid.
So that’s it for astronomy from the southern hemisphere. If I find time, I may put together a photo album of all the images I’ve made down here but there won’t be anything new. The scope is disassembled and about halfway packed. About 3am on Saturday morning, I looked north and saw the Summer Triangle, badly misnamed here where I was shivering in 30 degree weather, standing upside down with Vega and Deneb about 10 degrees off the northern horizon. I realized that it will be very nice to again see the stars with which I’m familiar.