UNIVERSITY OF CALIFORNIA OBSERVATORIES/LICK OBSERVATORY A BRIEF GUIDE TO THE NICKEL 1-METER REFLECTOR INTRODUCTION BACKGROUND OPTICS TUB TV GUIDER LIMITS DATA TAKING AND ANALYSIS TELESCOPE CONTROLLER AUTOGUIDER 1-M and 3-M COMPARED Introduction ============ The Anna L. Nickel 1-Meter Reflector has been in operation on Mount Hamilton since 1979. It is a highly automated, modern telescope which supports several Lick facility instruments for spectroscopy and imaging. What follows here is merely a brief outline, and is in no way meant to substitute for the telescope manual. For more complete information, please refer to Lick Observatory Technical Report No. 36, which may be available from your local reading room or from a fellow observer. 1-meter observers may obtain single copies for their own use from the Lick Observatory Publications Office (publof@ucolick.org). The 1-meter is available to the University of California astronomical community by subscription. Prospective 1-meter users must complete an observing time request form. The 1-meter is a user-operated telescope. All new users must be checked out by a resident astronomer on their first night. Please ask for this on your time request. Please direct questions to Tony Misch (tony@ucolick.org) or Rem Stone (rem@ucolick.org). Background ========== The Nickel Telescope is one of the newest on Mount Hamilton, but occupies the oldest dome. It was put into operation in 1979, in the dome that, since 1881, had been home to the Clark 12-inch Refractor. The 1-meter was designed by Lick personnel and built in the Lick shops, with funds provided in a bequest from Anna L. Nickel. The Nickel is a highly automated, modern telescope, operated remotely from a control room adjacent to the dome. From an observer's standpoint, it is harder to use than the Shane 3-meter telescope because no Telescope Operator is provided, so observers must learn to safely and efficiently operate the telescope on their own. But thanks to automation, reliable design, and friendly software, it is not difficult to learn. Observers cannot check out other observers; training for new users, or returning users who feel the need of a refresher course, must be provided by one of the observatory's support astronomers. If you have not observed with the 40-inch for some time and feel uncertain about using it safely and effectively, you are urged to ask for refresher instruction on your time request. Optics ====== The Ritchey-Chretien optics utilize an f/5.3 primary mirror of 38-1/2" diameter, and a secondary providing an f/17 cassegrain focus--the telescope's sole focus--with an approximate scale of 12.25 arcsec/mm. About 12% of the light is blocked by the secondary. (An f/17.5 chopping secondary may be mounted for IR work. Please specify this in advance on your time request.) Telescope Utilization Bin (TUB) =============================== The Telescope Utilization Bin (TUB, or more colloquially,tub) is that portion of the telescope below the primary mirror cell. It contains the TV acquisition and guiding system, the diagonal mirror system used to direct a portion of the beam to the guide camera, and a selection of comparison lamp sources (He-Ar, Hg-Cd, and Ne). The tub also serves to carry the cassegrain instrumentation which hangs below it. The tub can be rotated, but for a given instrumental setup, the tub position angle is preset by the maintenance crew to ensure proper balance of the telescope as a whole. Acquisition and Guide Camera ============================ The full field of the TV camera is about 5'40" x 7'20" (arc). Color sensitivity ranges from below 4000A to about 1 micron. The integration time may be varied from a minimum of 0.7 sec to about 30 secs. On a clear dark night, this is sufficient to see objects at the limit of the (old) Palomar Sky Survey. The moon and San Jose often mean one cannot see quite so deeply, however. You can mount single 2" x 2" filters in a plastic holder which snaps into place on the camera lens. Sensitivity of Acquisition and Guide TV Camera (faintest star seen with 1/2 moon in average seeing) ==================================================== minimum gain, no integration 11th magnitude maximum gain, no integration 15th magnitude maximum gain, full integration 20th magnitude Telescope Limits ================ Wind: 50 mph Humidity: When alarm sounds above 0 degrees centigrade, or 95% on the gauge if at or below 0 degrees; or as necessary to exclude moisture Hour Angle: 5h 30m Dec: With spectrograph: +58.5 to -19.5 degrees Otherwise: +67.5 to -30.17 degrees Zenith distance: 65.5 degrees Data-Taking and Analysis ======================== Data taking is done from one of two computers in the control room, depending on the instrument in use. The data-taking software is displayed in three x-windows: 1) a data-taking window displaying a menu-driven system for controlling observations, 2) an image window in which raw images are displayed as they come in from the detector (and in which stored images can be redisplayed), and 3) an accompanying image-control window for simple manipulation and analysis of the image. Most observers find the data-taker to be extraordinarily easy to use. More rigorous data analysis can be done using one of several packages available on the mountain. These include Vista, IRAF, and IDL. For convenience, these are generally run on the computer not in use for data-taking. The disks of the two computers are cross-mounted, giving the reduction software quick access to either machine. The computers, an Integrated Solutions 68030-based workstation and a Sparc 5, run UNIX and X-11. Both are fully networked, so observers can choose to access their home machines for data reduction and other tasks. Netscape is available on the Sparcstation. (Long-term plans call for phasing out the ISI, but hardware restrictions require it for data-taking at present.) Data from all Lick instruments are stored in FITS format. An Exabyte tape drive is used for storage. 8-mm cassettes can be purchased on the mountain. Telescope Controller (Telco) ============================ Telco provides various automatic and automated functions for controlling the telescope and dome. TV and autoguider ================= The autoguider gets its data from the TV camera image. With the autoguider joystick you position a reticle over the guide star image on the TV monitor. The reticle is divided into four quadrants. The autoguider finds the balance of light between the four quadrants, and guides the telescope so as to maintain that balance. Major Differences Between the 120" and 40" ========================================== Many observers come to the 40" with prior experience with the 120" CCD spectrograph, and vice versa. If you are used to the 120" setup, the major differences you will find are as follows: A night assistant is not provided, so you must be a lot more self-sufficient. In general you will be busier, but perhaps that's just as well because there's less outside stimulation to keep you awake! You must learn to do more things, such as entering the star coordinates into the telescope setting program, actually setting the telescope, using Telco and operating the autoguider. It is not possible to switch between direct and spectroscopic modes. At the 40" the TV is not mounted on a movable stage, so you cannot search around for an offset guide star. In spectroscopic mode you must guide off of the slit, and in direct mode you get one fixed offset field in which to find a guide star. There is not a fancy reticle projected onto a pellicle for the guide TV. There are the same three cursors (+) which you can move around on the TV, but most people just mark on the screen with a grease pencil. The line lamps at the 40" are switched from the data taking terminal main menu. The x-stage for the spectrograph is controlled by computer, which makes it easy to change central wavelength during the night. There is a choice of lenses for the spectrograph camera. There are only two diagonal mirror positions at the 40", which correspond to positions 2 and 4 at the 120". FINAL COMMENT: If you are a first time user, PLEASE get the manual and read it, particularly the sections "Step by Step Procedures: What to Bring", and "Arriving at Mt. Hamilton." It will make both your life and ours much easier.