Telescopes I've Used - Cerro Tololo Inter-American Observatory

Cerro Tololo Inter-American Observatory, Cerro Tololo, IVa Region, Chile

CTIO from the air The southern-hemisphere counterpart to Kitt Peak, Cerro Tololo is situated in the foothills of the Andes, above the Elqui River valley inland of La Serena. As seen in this aerial view, Cerro Tololo isn't a very impressive summit compared to the spine of the Andes, but it's high enough for good seeing and not high enough for really severe weather (yeah, I can say that, not having been one of the astronomers who had to walk down off the mountain following a July blizzard). The site has spectacularly dark skies, supporting studies of galactic structure and the Magellanic Clouds in particular, as well as that part of the deep extragalactic Universe that isn't accessible to the more numerous Northern Hemisphere facilities. The flat mountaintop is very crowded, with the 4-m, 1.5m, 0.9m Curtis Schmidt, 1.0m (former Yale), 0.9m, and two domes for 0.4m instruments, so that the new SOAR and Gemini-South projects are being erected on nearby Cerro Pachon, affording much more real estate as well as probably better airflow and seeing. Several visitors have remarked that the Maya-style buildings and their east-west alignments give a particularly mystical aura to the mountaintop. (Before I hear complaints, yes, I know that the Maya were thousands of miles north on a different continent - but I didn't invent this stuff.)

CTIO domes in twilight CTIO domes by moonlight CTIO domes, and star trails in Crux

Whenever the opportunity presented itself, I've sneaked over to the 0.4m telescope dome (little used these days) and used it for piggyback photography and that perennial favorite of NOAO proposers, visual observations of deep-sky objects. Here are some samples of how dark and clean the sky can be in Chile, limited by my cheap scanner. There's also a nice wide-field view of the Galactic Center taken from a 35mm slide.

Piggyback photo of Orion Piggyback photo of the Large Magellanic Cloud

One bit of wildlife at Cerro Tololo that is especially impressive to most of us is the condors. On most days, at least one can be seen wheeling, gliding for what seems like hours with only slight trim to the wingtip feathers. Occasionally some of the cooks will throw one a whole chicken. It's attention-getting to hear a rapping on the dining-room window, turn around, and see a bird looking you right in the eye. Also noteworthy are vizcachas, which look at first like large grey rabbits until you notice the long, bushy tail and squirrel-like movements. They have a particular habit of appearing at sunset, giving every impression of thoughtfully contemplating sundown from a rocky perch.

Condor eats at Cerro Tololo

4-m Victor Blanco telescope
CTIO 4-meter dome CTIO 4-meter telescope

I used this instrument for imaging and spectroscopic studies of optical jets (and candidate jets, most of which don't pan out). As examples, here's one of the mysterious jets from the barred spiral galaxy NGC 1097, in a summed B+V mosaic shown in pseudocolor covering the area where the northwest jet takes a corner (the galaxy core is several field areas away to the lower right). After adding VLA observations, spectroscopic limits on emission lines, and some soul-searching, several of us concluded that the jets in this case are most likely starlight, perhaps from particularly odd tidal interactions with the close elliptical companion to NGC 1097. Or maybe not.

Dogleg jet of NGC 1097

For comparison, here is a color-composite image of the nucleus of NGC 1097, showing the central ring of star formation (which must be more elliptical than it appears, to lie in the plane of the galaxy), inner bar with prominent dust lanes, and central old stellar population (within which an active nucleus comes and goes, as seen spectroscopically). This was made from short-exposure B and V CCD frames with the Blanco 4m prime-focus camera.

Nucleus and ring of NGC 1097

1.5m telescope

CTIO 1.5 dome by moonlight CTIO 1.5m telescope For a decade the largest instrument at CTIO, this telescope is unusually well-equipped for its aperture. We've used it for identification of faint IRAS galaxies, and recently as a major part of the study Ray White III and I have done of dust in galaxies through the use of overlapping galaxy pairs. There's a law of nature which decrees that the most interesting galaxies in our part of the Universe are found at deep southern declinations. This instrument furnished our best set of overlapping galaxies, of which a couple are illustrated here. I also used it as part of a survey for possible optical jets in southern galaxies, which mostly turned up odd tidal features. A couple of examples are shown here in pseudocolor renditions of V-band images.

NGC 3314 color composite UGC 2942/3 color composite False-color view of AM 2316-272 False-color view of ESO 1438-39

Telescope Collection

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