March 18, 2013
First Light For Third 1-Meter Node Of Global Telescope
Las Cumbres Observatory Global Telescope
The first truly global telescope came a significant step closer to completion this month with the installation and first light on three new 1-meter telescopes at the South Africa Astronomical Observatory (SAAO) near Sutherland, South Africa. A team of five Las Cumbres engineers, technicians, and a postdoc, convened at Sutherland for three weeks during late February and early March to achieve this feat.
Las Cumbres Observatory Global Telescope (LCOGT) has installed four other identical 1-meter telescopes to date: an operational prototype at McDonald Observatory near Fort Davis, Texas (April 2012), and a full science node of three telescopes at Cerro Tololo Inter-American Observatory (CTIO) (October 2012).
Annie Hjelstrom, the project engineer responsible for the successful installation, pointed out that, "We had a great installation team, and SAAO and SALT staff were very helpful, but this is also the culmination of eight years of design and development. Each telescope is built, configured, tested, and then dismantled at the Goleta, California headquarters before we put them back together on site."
Usually first light images are fairly dry, and several such images were taken at each of the three telescopes. But for the SAAO node, LCOGT founder and lead engineer Wayne Rosing asked former company intern and accomplished astrophotographer B. J. Fulton to acquire images from three different galaxies using the stripped-down capabilities available during the early engineering phases. Fulton, who is now an astronomy graduate student with the University of Hawaii, produced the images over the first few days of telescope operations.
Edward Gomez, Education and Outreach Director of LCOGT, wrote that Fulton "kept the integrity of a first-light image by not touching up the images in any way." The images were created using command-line tools that work directly on the raw pixel data (e.g., Python, Stiff and ImageMagick). The images do not have flat-fields, darks or biases subtracted. They each combine multiple wavelengths and colors from the use of different filters on the telescope instrument. For example, the images of M104 and M83 each required over 3 hours of exposure time distributed across two Bessel filters with additional exposures using two Sloan filters. For Trumpler 14, Fulton, took over 2 hours of images spread across three Sloan filters. He was able to conduct his observations from Hawaii, while the engineering team in Santa Barbara conducted their tests and the installation team in South Africa completed system tuning and optical collimation steps.
The installation team consisted of Hjelstrom, technicians Mark Crellin from the Birkenhead, England office, Kurt Vander Horst and David Petry from the Goleta office, and astronomy postdoctoral scholar, Abiy Tekola, based at SAAO in Capetown. The telescopes arrived on site on February 18th and were craned into the domes the next day. The telescope in Dome A was assembled with electrical, mirrors, optical tube assembly, and instrument by the end of February 20th, and the telescope went on-sky that night to begin TPOINT runs to set the telescope's polar alignment. The second and third telescopes followed over the next two days.
The trio of telescopes brings the company's total of operational 1-meter telescopes to seven. Two more are planned for mid-May at the Siding Spring Observatory to complete the southern ring, and a second telescope will be installed at McDonald Observatory at roughly year-end to create the first northern node.