Observing in Chile - My First Night

Tonight was my first night of observing at a real telescope - the Magellan 6.5 m Clay telescope, in Chile! The telescopes are a short 3-minute drive from the dorms. On the ground level is a nice lounge and kitchen (!), and on the upper level is the control room, from where a door leads into the telescope dome.

In the control room, we met up with the Instrument Specialist in the early afternoon. The Instrument Specialist set up the instrument we were using: he put in the slits we wanted to use for spectroscopy (by changing the position of the slit on the sky, you change the angle the light hits the grating, and thereby optimise the grating to function more effectively at a different wavelength), as well as multi-object masks.

Each of these masks have lots of tiny slits cut into them, which we will align with stars in the sky, and then take spectra of the galaxies we have carefully chosen the slits to fall upon (taking care that the resulting spectra from different objects do not overlap). These masks are cut from sheet aluminium using a laser, based on mask files that my advisor sent to the observatory a month in advance of our run.

Next, the instrument specialist cleaned the primary mirror of the telescope, something that is done every week. We thus got a glimpse of the 6.5 m mirror in its full glory, as it was turned nearly face-on to

us! Here's a mugshot of me posing with the Clay telescope.

Next on the agenda was some calibration. We took some images of the blank dome during the afternoon, with the aperture wheel in various positions, to make sure that the slits and masks were mounted in the wheel in the order that the instrument specialist said they were. Then we imaged He-Ne-Ar lamps, to check that we'd set up the slits to give us the right sort of wavelength coverage. Finally, we took some bias images and headed back for dinner. Boy, it feels like we're always eating...

The afternoon brought some clouds, and we were a little worried that things would be bad at night. Thankfully, they blue over :) and everything has been clear all evening. We started the evening with twilight flats, followed by spectrophotometric standard stars for flux calibration. We then imaged some GRB fields, and took spectra of host galaxies. Excitingly, I got to image a GRB host galaxy that I have used in my research! The individual i-band frames do not show any detection at the expected location of the source, but stacking will tell so much more. We also used the masks tonight. He're a picture of my advisor and colleague, Wen-fai, getting the next mask ready, after I'd taken spectra with the first one. It promises to be a fun three days!