Last night I was at the Las Campanas Observatory (LCO) observing with the Henrietta Swope 1m Telescope. The observing program was aimed at detecting optical counterparts to X-ray sources which were serendipitously seen in other observations. Basically, we see X-rays from a region of the sky, but because we don’t have sensitive optical imaging, we cannot see the galaxy which is the source of the X-rays. So this is a multi-step process to characterize those X-ray sources. First, we need to find the optical galaxy counterpart (these Swope Observations). Then, once we’ve located the galaxy and know its approximate brightness, we can take optical spectra to determine its redshift, and use that to infer a distance. With the distance, we can calculate how luminous the X-ray source is, and the optical spectra can also help us tell what type of source it is (likely an Active Galactic Nucleus of some sort).

I flew to LCO on Thursday morning and hitched a ride up to the mountain that afternoon. The first evening was relatively relaxed – I got settled in before joining Markus Rabus on the Swope 1m, to see how the telescope worked before my run on Friday night. Swope is a bit different than most major telescopes in that there is no telescope operator provided. Typically, there is an operator who oversees the telescope’s physical operation and can provide some assistance to the astronomers who are collecting data. Generally, this includes opening and closing the telescope dome, focusing the telescope, moving the telescope to new targets, and so on. This leaves the astronomer to control the science instruments and monitor the acquisition of data. In Swope’s case, no operator is supplied, so the astronomer also needs to take care of the general telescope operations. I think it is a lot of fun to get to do those things, so I was glad to have the chance. But it also means more work and more things to do. So, I spent half of Thursday night watching Markus observe (well, most of it was spent waiting for the clouds to clear so we could open the dome), before heading to bed around 1am.

On Friday morning I rested as much as I could until lunch time, since I would have a long night ahead of me. After lunch I went to the telescope to take some calibration data and go through the motions of setting up for the night’s observing run. Unfortunately the weather was not looking promising, but I could at least make sure we would have all the necessary calibration data!

Image for Telescope Area

All telescope control rooms are cool, but this one had an extra special treat. The original 1970’s control panel was still an integral part of the telescope’s operation.

Image for Swope Control Room

The dials on the panel were all functional and could be used to determine where the telescope was pointed (though it is easier to use the digital readouts on the telescope control computer). The lower portion of the panel contained switches and knobs to control the telescope dome opening/closing, lights in the dome, telescope tracking, etc. Very cool.

Image for Telescope Control Panel

After some time taking calibrations and another quick training session from one of the LCO staff (thanks, Francisco!), I returned to the main lodge for dinner. At this point, the weather was not looking good, but one always needs to go to the telescope in case things clear up during the night (which, fortunately, they did).

Image for Hazy Evening

Observatories generally provide cars for the purpose of driving between the lodging, cafeteria, and telescopes, since they are generally not right next to each other. But I always prefer to walk to/from the telescopes. It is a nice opportunity to enjoy being in the mountains and take in the scenery. On the post-dinner walk to the telescope, I was treated to the view of two hawks soaring on thermals above the mountain, with the moon behind them.

Image for Hawk Soaring

The evening was fairly cloudy but we opened anyways, hoping we could get some useful data despite the clouds. If they were thin enough, we would still be able to see stars and galaxies, but measurements of their brightness would be less reliable and it would take longer exposures to see the galaxies.

Image for Telescope Looking Out

I love a good sunset, but good sunsets require clouds, so good sunsets at an observatory means bad observing conditions.

Image for Sunset at the 1m

But, I pressed on anyways. The start of the night was pretty bad. The clouds passing through often obscured the (bright!) star I was using to guide the telescope, so several frames were lost when the guide star was covered and the telescope started wandering. Fortunately the clouds thinned as the night progressed, though they never fully cleared. But I ended up getting good data on several targets.

The data will be used to look for galaxies which are likely distant and so appear small. But, occasionally a field has a big nearby galaxy in it, which makes for spectacular pictures. Here’s a raw image which includes the nearby galaxy NGC 4945 (12 million light-years away). It is a nearly edge-on disk galaxy; the dark patches are where dust in the disk is blocking light from the stars in the galaxy behind those clouds of dust and gas.

Image for NGC 4945 from Swope

Eventually the Sun began to rise, so it was time to go to bed. I finished a few more calibrations, closed up the telescope, and began the walk back to the dorms for a few hours sleep before my trip back to Santiago. Once again, my choice to walk was rewarded with this gorgeous view of Mercury and Venus rising over the domes of the twin 6.5m Magellan Telescopes

Image for Mercury and Venus Rising over the Magellan Telescopes

Five hours of sleep and a quick lunch later, I was riding down the mountain, to La Serena and my flight back to Santiago. Despite the cloudy start to the night, good data was acquired, so we will hopefully be able to identify a few more galaxies hosting active galactic nuclei discovered in the X-rays.

More photos from the observing run are available in the “Swope Observing” photo set.