Instrument & Computer Configuration
INFORMATION PROVIDED HERE IS FOR REFERENCE ONLY
Manuel Hernandez and Hernan Tirado are our Tololo computer specialists and can assist with the computer systems. They will assign you a visitor account number on the SUN computer network. You will be the sole user of this account while you are at CTIO. Each telescope has two SUN computers in the control room. The present configuration is that a SUN 10/41 operates the Arcon, and the data ends up on its disk. (or on the disk on an Ultrasparc). The below examples are described for the 0.9-m, but at the 1.5-m and 4-m the configurations are equivalent. At the 0.9-m this computer is ctioa4. The other SUN computer (at the 0.9-m it is called ctio36) has some of the peripherals (dat, exabyte, laser printer, mag tape drive) attached. You will find in the control room a full set of IRAF manuals, and COOKBOOKS containing advice and directions for reducing your data. Refer also to the manual: "The Arcon-IRAF Interface A Preliminary User's Guide for Direct Imaging".
Each telescope has a telescope control computer (TCS). On the 4-m and 1.5-m this is a VME bus computer with a program written in C. The 0.9-m has a DFM Engineering TCS. The TCS computer will be operated by your Observing Assistant at the 1.5-m but at the 0.9-m you will probably be on your own. Refer to "The 0.9m Telescope"
All hardware functions in the CCD camera head (with the exception of the CCD shutter are controlled by a STD bus computer (actually a PC) mounted on the telescope. The operation of this computer should be transparent to the user. At the 4-m and 0.9-m, the light is reflected from only the primary and secondary mirrors before passing through two filter bolts, and finally a fused silica window before reaching the CCD. On the 1.5-m f/7.5 and f/13.5 there is a fused silica corrector element above the filter bolts. Each filter bolt can hold up to seven 3 inch square filters, which must be less than 1 cm thick, plus a clear position. There are 3 inch square UBVRI sets for use with the Tektronix CCDs. A single 5-position module which holds up to five 4x4 filters can be used if need be. In all cases the CCD is focused by moving the telescope secondary mirror. The filter bolts are contained in a shutter-filter unit, which also holds dark slides (manual), preflash arm and light-emitting-diodes (leds), plus a shutter. Your telescope will be operated by an Observing Assistant who is familiar with the operation of both the telescope and the CCD system. The Observer Support section will have helped in the setup and check out the instrument, and they will respond to any problems that might arise. The telescope should point to better than 10 arc sec rms (0.9- m, 15 arc sec rms) assuming accurate input co-ordinates. If the pointing is much worse than this then you should complain; on the 0.9-m and 1.5-m the collimation co-efficients may not have been re-entered following reset of the Telescope Control System. It is a short (10 min.) procedure to re-determine the collimation coefficients).
Peltier cooled CCDTV cameras are used for acquisition and guiding. The configuration is different for the three telescopes. At the 0.9-m the TV can be scanned in 1-D over an area approx 12x3 arcmin. The useable field is a little less than 4x3 arc min. At the 1.5-m the TV is mounted on an X-Y stage ("the GAM") which can be moved until a guide star is found. At the 4-m, the TV views a fixed position of sky via an f/2.5 focal reducer. The guiding is done in a PC via a program written by Steve Shectman (LCO).
Observers needing further information should consult the following persons, in the first instance contacting people who are actually on Tololo at the time:
- General help on the mountain: Luz Pinto (Mon.-Fri.), Marco Nuñez (Mon.-Fri.). On weekends the paramedic in the clinic can help with general issues.
- Questions regarding observing procedures: the current Telescope Operations Support staff on duty (Hernan Tirado, Manuel Hernandez, and/or Leonardo Paredes), the SMARTS Coordinator Jennifer Winters (GSU), CTIO/SMARTS 0.9-m Observatory Director Todd Henry (GSU)