The Discovery Channel Telescope (DCT) is a wide-field 4.2-m diameter optical-infrared telescope being constructed by Lowell Observatory and scheduled for first light in mid-2011. The $42M telescope was funded entirely through private donations - largely from Discovery Communications and its founders the Hendricks family - and is located on the dark and high-altitude site of Happy Jack Mountain, near Flagstaff, AZ. In addition to its planned use toward understanding the stellar content of galaxies, star formation in interstellar clouds, cometary dust and gas, and Kuiper belt objects, the DCT is in the remarkable position of being the focal point of an ongoing variety of astronomically-related multimedia programming for an established world-wide audience of more than a billion subscribers.
With support from NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program, Dr. Philip Massey of Lowell Observatory intends to construct a wide-field imager for the DCT using a state-of-the-art CCD that will be the largest single square device possible on the 150-mm silicon wafers used in today's semiconductor foundries. This 6144 x 6144 (38 megapixel) detector will be teamed with corrector optics, a wide assortment of remotely-selectable filters, and guider hardware to make up the workhorse research instrument on the telescope for at least the first several years of use. The imager will also provide the scientific material and large-scale astronomical images to highlight the educational programming on the Discovery Channel and for outreach programs to the 80,000 members of the public who visit Lowell Observatory annually.
The Discovery Channel is renowned for producing entertaining and educational programming relating to scientific discovery and achievement. Their production for the DCT will include a documentary on the construction of the telescope itself, features on the astronomical instrumentation in use, on the research programs underway, and short spots called "Tonight at the DCT". Lowell astronomers will participate in preparing and vetting these programs for scientific accuracy and relevance, as well as in using the DCT for many of the educational programs that the observatory sponsors. The latter range from graduate student research programs, to Research Experiences for Undergraduates (REU) programs, to outreach activities into the public schools of Flagstaff and the surrounding Navajo and Hopi nations.
This grant allowed us to build an optical camera for Lowell Observatory’s new 4.3-meter Discovery Channel Telescope (DCT), which Lowell now operatesin partnership with Boston University, Northern Arizona University, the University of Maryland, and the University ofToledo. The camera is called the "Large Monolithic Imager," (LMI) as it is based upon the largest CCD that can currently be manufactured, 92.2 mm by92.4 mm (about 3.6 inches on a side). The device was manufactured by the e2v corporation in the UK, and our grant helped pay for the non-reoccurring engineering costs involved with e2v developing the first of these, plus the design and construction of the instrument,including the field-flatter, 18-position filter wheel (and 8 filters), and the commissioning of the instrument on the telescope.The LMI is now being used for astronomical observations nearly every clear night on the DCT. Most astronomical cameras are mosaic of multiple CCDs. For instance, the Mosaic CCD camera used on the Kitt Peak Mayall 4-meter consists of eight 2048x4096 CCDs arranged to cover an area of about 125 mm on a side. However, in doing so, there will be smallgaps between adjacent CCDs. Our single CCD has almost the same physical size, but no gaps. This allows us to measure the veryfaint outer halos of galaxies far better than we could with a mosaic, as one needs to dither the telescope to fill in the gaps witha mosaic, and unfortunately the sky brightness is constantly changing. In addition, the use of a single device allows more accuratephotometry, as our one device is much more uniform in its response to different colors of light than eight separate devices would be.Finally, it is our expectation that these large 61644x6160 devices will become common, and form the basis for future mosaics. Our camera was built on-schedule and on-budget, and is being used by Lowell astronomers, faculty at our partner institutions, andtheir students to conduct astronomical research. Programs that are currently active span the entire range from studying near-earthastroids zipping by the earth of 20,000 miles to studies of distant galaxies. In addition to the science component, there is a strong broader impact component as well. First, university students are already usingthe telescope for their research. Secondly, faculty at these institutions are bringing their undergraduate students to observe withthis state-of-the-art instrument. The PI’s own "Observational Astronomy" class at Northern Arizona University used the telescope to take images last November, learned how to process these data, and turned them into pretty pictures. We have also assembled our ownpicture gallery, and make these images available to other astronomers and the public for any (non-commercial) use, including inclusionin text books. This is in accord with the NSF’s goal of increasing the public’s scientific literacy (short but accurate descriptionsare provided with each image), and the increasing the public’s engagement with science and technology. For the past 25 years, Lowell Observatory has hosted the MIT Field Camp in January; undergraduate students from MIT (and now Wellesley)spend three weeks at Lowell working with a mentor. This past January two women undergraduates helped us in our LMI commissioning effortsby characterizing and fixing an issue related to residual images and the linearity of the instrument, learning how to take data, reduce it,and analyze it as well. The NSF supports the full participation by women in the sciences, and this training was in accord with that goal. Our on-line picture gallery can be found at www.lowell.edu/techSpecs/LMI/gallery.html. A few sample images (not at full resolution) are provided here as well.
