Mees Observatory telescope checklist

Transcription

1 Mees Observatory telescope checklist Last revised 30 April 2003 DMW Startup 1. Turn on all circuit breakers in the breaker box by the front door. (Those with tape on them are always on; don t turn them off.) 2. Plug in computer console in warm room (Figure 1). 3. Check switches on telescope control system (TCS) front panel (Figure 2). The HALT MOTORS button should be pushed in, TRACK/OFF and EXTERNAL COMPUTER/OFF should be set to OFF (switch down). All other switches on the upper row (TRACK/AUXILIARY TRACK, DRIVES, AUTO DOME, DOME TRACK), and the MTR DRIVER CHASSIS switch (locking toggle switch between the fuses) should be in the UP position. The lowest row of switches should have the EAST/WEST switch on EAST, and the HARD LIMIT OVERRIDE switch OFF. Figure 1: computer console in control room. Left to right: the (downstairs) user interface computer (UIC), telescope control system (TCS), CCD camera computer, and Bob Slawson. 1

2 Initial switch settings: In U-D-U-U-D-U U U-off-off Figure 2: the Telescope Control System (TCS) front panel, and the settings that the switches should have before the system power is turned on. U = up, D = down. 4. Turn on system power (middle switch in the lower row). 5. Turn on telescope control computer, which is behind the door that hangs from that hinge visible on the front panel. 6. Let the TCS computer boot. Check the date and time (type DATE or TIME <RETURN>, at the DOS prompt), and correct them if they re off by more than a few seconds. Note that it is universal time (UT) and date that is required (5 hours ahead of standard time, 4 ahead of daylight savings time). If your watch is not synchronized to UT, and you didn t bring a cell phone or a GPS receiver (both of which give you time synchronized to UT), then pick up the phone and call a friend to help you find out. If your friend happens to be sitting by a networked computer, he or she can look up UT for you on the US Naval Observatory website, Make sure you enter times either in 24-hour format, or with a P for PM or A for AM. 7. Make sure the EXTERNAL COMPUTER switch is still OFF and type TCS <RETURN>. The telescope operating system will take a few minutes to initialize, the longest step being the finding of the focus reference point (fiducial). You ll have to wait until it s done initializing the focus before proceeding with instructions to the TCS computer. 2

3 8. Push the HALT MOTORS button, so that it is in its out position; this un-halts the motors. Check upstairs to make sure the telescope isn t moving; if it is, then HALT MOTORS again, turn off the TCS electronics and computer, and start over at step Check the TCS computer s UT, on its monitor display, and set if necessary. (It should be correct, if step 6 succeeded.) Now check it again. Setting the time wrong has been the most frequent error in telescope setup, by far. Offset guider Mirror lever (as shown, the eyepiece is selected) Filter wheel CCD camera Eyepiece Eyepiece positionadjustment knobs Filter-wheel motor Figure 3: the back of the telescope, showing the RIT 4kx4k CCD camera and filter wheel, the offset guider, and its eyepiece, with some crucial features labelled. 10. The necessary focal plane equipment should already be installed. On the back of the telescope you will find the eyepiece and one of several CCD cameras, both mounted on a metal box called the offset guider (Figure 3). The offset guider contains a mirror that can direct light from the telescope either to the camera or the eyepiece by moving the lever on its north side. The eyepiece can be translated around by turning the two offset-guider knobs. If you will be using the eyepiece as you will, when giving tours translate it to the center of its range in both directions, if it isn t there already, and turn the mirror lever away from the eyepiece, to the position shown in Figure 3. 3

4 You may use any of the CCD cameras on which you have been checked out, as long as your observations do not interfere with public tours or approved research observations. Contact Bill Forrest or Dan Watson if you want to learn how to use one of the CCD cameras in your observations. 11. Unlatch both of the locks on the gears of the dome-door mechanism, remove the hooked rubber strap on the doors, and open the dome. Make sure that whatever may fall in (leaves, snow, tourists ) gets cleaned up and doesn t get all over the telescope or instruments. 12. Slew the telescope to the south, and remove tarp and covers. 13. Unless you know for sure that the last observer left the telescope properly at zenith, put it at zenith according to the dials on the telescope base, as shown in Figure 4. The hour-angle dial (the smaller of the three) should read precisely zero. The declination (right-hand) dial should read the observatory latitude: 42 degrees, 42 arcminutes. Make sure you re reading the dial and tick-marks correctly: for northern latitudes the declination increases when the needle moves counterclockwise, and each degree is subdivided on the dial into ten-minute major intervals and two-minute minor intervals. The correct reading is just past 40 on the coarse (small) scale, and 242 on the fine (large), counterclockwise scale. This latter setting is illustrated in Figure 4. As soon as this is done, return to the control room and set the telescope position to RA = sidereal time (ST, found on TCS display, underneath the UT), Dec = latitude ( ): go to the Initialization menu of TCS, choose Set Telescope Position, and type in the ST where RA goes, the latitude where the Dec goes, and the current epoch (e.g for 1 July 2003) where the Epoch goes. The best way to do this is to type in an RA about thirty seconds later than the ST indicated, enter the rest of the information and proceed to the Any changes prompt in less than thirty seconds (during which ST keeps increasing, of course), and hit the Enter key in reply to this prompt as soon as the RA you entered matches ST Figure 4: the right ascension, hour angle, and declination dials, left to right and set correctly for zenith, and a schematic diagram of the high-resolution circle on the declination dial, with an angle of 242 indicated. 4

5 14. You have a choice of two user interface computers (UICs): the one in the control room to the left of the TCS computer, and the laptop that is stored in the gray metal closet in the control room. The one to which the TCS computer talks is selected by the cable switch that sits to the left of the TCS computer s monitor. If you re running a public tour, you will probably want to use the laptop; set the cable switch for Upstairs, and take the laptop and some serial cables (also found in the closet) up to the dome floor. Connect the serial port of the laptop to serial cable #4, found near the base of the telescope on its east (left) side. Now turn on the user interface computer, whichever one you re using, and let it boot into Windows. 15. Run TheSky, using the icon on the UIC s desktop. 16. In the Data menu of TheSky, check the Site Information item to see of observatory position and time are set correctly. (They should already be.) 17. Then in the Telescope menu item of TheSky, choose Link Establish Link. The telescopeposition bullseye will appear on the screen at the current telescope position. If a link cannot be established, check the cable-switch box. 18. Turn the TCS electronics TRACK/OFF switch to TRACK. This should change the RA rate from zero to on the TCS monitor screen. 19. Choose a bright star close to the zenith in TheSky s display: click on it to bring up an information window, center the star in the display if you want (button in lower left corner of information window), and command the telescope to slew to the star (fourth button from the right at the bottom of the information window. If you want to go to an object for which you know the name, use the Edit Find menu item. 20. With the dome paddle, turn the dome slit in front of the telescope. Check visually to see that the telescope is pointing in the right direction: for example, one can stand behind it and look for the target through the dome slit, in line with the telescope. (If the telescope is way off, check again to see if UT is set correctly.) With the telescope paddle, center the star in the field, and focus the telescope. The SET mode (hold down the paddle button with that name) provides a good speed for moving the star within the guider field, and for focusing. If the telescope is way out of focus, the image will not look starlike: it will look like an illuminated image of the primary mirror, with the shadow of the secondary mirror and its supports superimposed. Note the FOCUS position on the TCS monitor display, and write it in the Observing log book. If you don t see the star, zoom the display in on TheSky until the display is just a few fields-ofview across. If there are any stars visible in the field you may identify them by comparison to the display (eyepiece or CCD), and move the telescope to the target accordingly. If not, move the telescope around systematically in a grid pattern of, say, ¾-field-of-view steps, using TheSky s display to guide you, and find your target. If you still can t, then send the telescope back to zenith and start over at step In the Initialization menu of TCS, set the telescope position to the RA and Dec of the star. The current-epoch position of the star is given near the top of TheSky s information window. Now you should be able to point the telescope confidently to other objects (within an arcminute or so), either with TheSky or with TCS. 5

6 Shutdown 1. If a CCD camera is in use, shut down its control program, and turn off the camera electronics and refrigerator (if it has one). 2. Turn TRACK/OFF switch OFF. 3. Slew telescope to the service position, and put covers and tarp back on. 4. On TCS Movement menu, set telescope to zenith (5 <Enter>) and enable slew (7 <Enter>). 5. Once the telescope has arrived at zenith, push in the HALT MOTORS button on the TCS front panel. 6. Move the dome until the slit is directly over the doorway that leads to the deck. Close the dome, lock the gears of the dome-slit mechanism, and secure the doors with the hooked rubber strap. Again, make sure that whatever may fall into the dome when the doors move gets cleaned up, and doesn t get on the equipment. 7. Make sure everything electronic or optical in the dome is protected by a tarp. Pay special attention to covering the CCD camera electronics. 8. Shut down TheSky, and the UIC on which it runs. 9. Turn the TCS SYSTEM POWER switch OFF. 10. Unplug the console in the control room. 11. If you used the laptop computer, make sure it, and the serial cable, is put back in the gray metal closet in the control room. 12. Make sure that ALL of the doors to the rooms inside the dome are closed. 13. Turn off the breakers that you turned on, on the way in. 14. Lock the door behind you. 15. If you went into the Gannett House, make sure that its doors are locked. Even if you didn t, please make sure that the floodlights outside the house are turned off. There s a switch for these lights, between the garage doors, that may be partially hidden by ivy. 16. Make sure the gate is locked securely behind you. Now you are ready to drive home. Be careful of the deer. 6