Canopus Observatory: Notes for Observers v.7.1
By John Phillips, Duncan Galloway, John Greenhill and Paul Cieslik
21st May 2001
Current warnings, problems and tips
- Weather station, coolant pump and dome fans
- Open dome doors
- Powerup telesope
- Turn on computers (5,6) and mirror fans
- Telescope drive computer: Set time, check filters (13)
- Start Cicada and begin temperature regulation
- Turn on telescope drive power (8)
- Turn on monitor (12), focussing gear (3), IIT etc. (9,10)
- Check the Cass TV mirror drive
- Turn on image intensifier (10)
- Check filters via Cicada and Olivetti PC (7)
- Setup ST4 computer
- Start dome position control
- Select star to use for zeroing
- Drive to star
- Center star using guide camera position
- Fine tune position using Cass. camera position
- Set offsets using ALT-O
- Choose C (clear) filter
- Select subframe
- Start auto acquisition and display
- Set voltage to give best focus
- Adjust periodically throughout the night.
- Check ST4 settings
- Take a dark frame
- Initiate tracking
- Select target star for guiding
- Return dome to parking position
- Shutdown Cicada
- Turn off image intensifier (10) and close guide telescope shutter
- Return telescope to parking position
- Turn off telescope drive power (8)
- Turn off mirror fans, computers, and video amplifier
- Turn off dome fans, coolant pump. Retrieve bladder from esky
- Turn off telescope hardware and close petals
- Replace baffle cover and close dome
- Archive data
- File observing report
Current warnings and tips
17/5/01 - Telescope drive in an anomalous state
- Occasionally, usually during start-up, electrical interference puts the telescope controller into an anomalous state with several (usually slew and set or guide) buttons actuated simultaneously. This is a dangerous situation since computer control fails and the telescope keeps driving until the limits are reached and the alarm is triggered. If you see the problem before the alarm is triggered press the large red mushroom shaped Emergency Stop button. The alarm will sound briefly and the telescope should slew down and stop. If the conflicting drive light buttons do not go out you should then press the Reset button under the clear cover. If you hit the limits first the noise will be unnerving so first grab the ear muffs on the wall to the left of the control panel. Then press the Override button. This will stop the noise so you can check out the situation. If you have driven the altitude below 20 degrees you will have to drive the telescope back up in altitude to above about 28 degrees while holding your finger on the override button. Be careful you are driving the right way. It is best to drive first using the set buttons while watching the altitude. If you have driven into the South pier you will need to go into the dome (with ear muffs on!) to check out how best to drive away from the pier. Then go back inside, hold your finger on the override button and drive away from the pier guard wire.
- It is known that the telescope position controller can suffer from spurious mains power borne noise, this has been particularly noticeable when computers and other equipment are turned on in the control room. KB recommends that the position controller be turned on last and off first
- If the dome angle display shows HLP --- there has been a reset probably caused by a power failure. When suspend is turned off the dome will seek the 000 calibration mark and then stop ready for use.
- If the display shows --- --- there has been an unknown interrupt and the controller will need to be turned off then on to reset it (the power switch is on the rear of the box). The auto calibration process described above will then occur. Unknown interrupts should not happen please report this event so some engineering action can be taken.
- In case the automatic dome position control is inoperative, there are manual controls located on the wall of the dome near the drive motor (east wall). These controls cannot be used until the "Manual" button is pressed on the control box. If dome position is to be undertaken manually, the dome position will need to be checked every time the telescope moves to a new source and every 5-10 minutes or so if staying on the one source. Check carefully to make sure the telescope is pointing cleanly out the slit and the aperture will not be partially covered by the edges of the slit.
If pressing the manual button on the control box on the wall of the dome does not bring the green light on, check circuit breaker YELLOW 2 in the second row from the bottom in the switchboard located in the workshop.
- Occasionally when trying to change the Cass mirror (IOP) position the message "Time out for reply from TTC" appears on the Telescope Control Computer. At the back of the new "SHAFT ENCODER PROCESSOR" box (top left, replaces the old MTC controller (1)) there is a DB25 plug on the left hand side of the box (facing the rear). Atop the plug is a white switch, press the switch and wait about 20 sec before trying again.
- Engaging the auxiliary dec drive sometimes causes the telescope to drive south a considerable distance (up to about an inch on the TV monitor (12)). A solution is to line up the field with about the same offset to the north. If engaging the drive does move you south you should be close to the right position. If it does not, you can move south manually using the Guide controls on (15). Note that the auxiliary dec drive is not necessary when using tip-tilt autoguiding.
- There seems to be a problem with obtaining ideal focus. Even with the best possible setting stars are still noticeably elongated diagonally from lower left to upper right. This is probably due to poor alignment of the mirrors and will not be fixed until they are next removed.
- Occasionally the message "NO MTC SERIAL" appears on the telescope control computer. When this appears the RA readout may fail and dome driving may not work. Solutions seem to include doing nothing (the message may disappear on its own - unlikely) or changing the position of the Cass mirror from I to O or vice versa (and then back again). Changing filters and changing back should also fix the problem. Pressing the Reset button on the MTC control (1)
13/5/99 is a last ditch solution as it requires resetting the RA and Dec encoders.
- There seems to be a problem with the topmost north button in the Guide cluster on (15). During drive-to operations it seems to get hung up with this button lit but no movement in Dec. Press ESC on (13) to cease driving and finalise the telescope position manually.
- Remove the cover from the rain sensor and cloud detector located west of the observatory. The switch for the cloud detector is on its base, south is on and north is off. Disable the alarm in the corridor (on the left as you go in) if necessary. Then switch on the coolant pump in the RA drive/ Coude optics room. The motor current should be about 3 amps. Now go into the control room and turn up the Peltier power supply (5) to 3.5 amps using the coarse voltage control knob.
- The dome doors must be opened before the petals on the telescope so that debris dislodged during the roof opening does not fall onto the mirror. Climb the stairs to the platform level with the dome. If the previous observer has done the right thing the dome doors should be accessible from here. To the left of the doors is a box with controls for opening and closing the doors. Hold down the "open" button until the doors reach their full travel. You might like to briefly hold down the "close" button to take some of the tension off the ropes after this. On the right hand side is the infrared control box, turn this on if it is not on. You can now use the remote controller to open or close the doors from anywhere in the dome in case of rain.
- Climb the stairs to the top of the telescope platform and carefully remove the "top hat" cover over the baffle poking up through the petals. You can also remove it from the hoist using the blind roller on the hoist. The hoist must be driven right up as far as it will go without hitting the photometers to do this. Put the hat somewhere safe (wearing it is frowned upon).
- Ride up on the hoist until the floor of the hoist is about level with the bottom of the telescope - the best position will depend on your height! Watch very carefully to make sure that the hoist is not going to collide with the telescope. It gets moved around during maintenance operations and there is no guarantee that it will be in exactly the right spot afterwards.
- Next to the spotting telescope on the left is a vertical power board of mains switches. The third from top switch is for the Leach controller which should remain on at all times. Turn on all the other switches.
- On the right is a frame containing two grey boxes at top and bottom, the SDSU controller power supply, and the peltier cooler power supply. Rotate the voltage control on the top box fully anti-clockwise - it should have been put in this position when last shut down. This turns the image intensifier voltage right down. Then turn on the switches on the two boxes (NB: Some observers leave the switch on the bottom box on always since it is also switched by the bank of mains switches you have already turned on. If a red warning light on the top box comes on, this indicates that the image intensifier has been left on in the control room which is BAD considering you have all the lights on in the dome. Switch off IMMEDIATELY and turn the image intensifier off in the control room before proceeding. Once all is well you can turn the voltage control back to the fully clockwise position. On applying power to the bottom box you should hear a stepper motor driving the Cass. camera mirror. It should stop after 30-60 seconds. If is does not, press the reset button on the left of the lower grey box. Facing you are two pull-cords that open the flaps of the four mirror-air-flow fans. Open the flaps fully and secure the strings in the notches in the plastic string guides.
- Finally open the petals. To make sure they are fully open, pull the two strings tight and fasten them to their string guides. The left cord has a knot that should be pulled through the notch to ensure it does not slip. Then lower the hoist.
- Open the dome ante-room doors and turn on the big fan that blasts outside air through the dome. Follow the power cord from the ante-room to another power point near the south pier.
Finally switch off the dome lights.
Control room setup
Refer to the photo of the control room instrument console to identify the various bits.
- First turn on the computers using the clear covered switch on the auxiliary control panel (11). Also turn on the telescope tube fans and turn off the red dome lights. You can turn on the image intensifier at the same time if you wish. These switches are all located on the auxiliary control panel. The image intensifier (IIT) will not come on unless the dome light level is very low.
- Into the 486 Telescope Control Computer "COORD" (13) enter the current date and the 24-hour time from the crystal clock (4). This needs to be accurate to about 1 second. We use EST time (UT+10) all year. When the COORD display is present type CTRL + F4 and SHIFT + O to select the target list required. In 2001 we use p01.tar
- Camera control is now achieved using a dedicated Sun Sparc 20 workstation which is located on the bench adjacent to the main control station. Log and start Cicada at the prompt by typing cicada. In the small window which appears, select "Start Observing" and "UTAS". The window which is opened is the main observing window. You may get a warning message regarding modified FITS header keywords. Click on "Show", enter the appropriate details (mainly the observer's names) and click on "Apply" followed by "Dismiss". Click on the small thermometer icon at the top to display the temperature control window. Set the desired temperature (e.g. 220 degrees Kelvin) and click on "Set temperature". This will start the temperature regulation process.
You may get timeout errors indicating that the computer is unable to communicate with the camera. JG advises that this is likely to occur only when the Leach controller has been shut down. In this case it may be necessary to shutdown Cicada and turn the power to the controller at the telescope off and then on again. Sometimes this need sto be repeated several times until communication between Cicada and the controller is estblished.
Under the "Preferences" menu choose the directory to save the night's images in. A dialog box should appear warning that the directory does not yet exist. Click on the appropriate selection to create it.
- Switch on the telescope drive power by turning the key on the box with the large red knob (8) clockwise a quarter turn. After a 10s delay this will power up and you can then press the "TRACK", "N/S" and "COMPUTER CONTROL" pushbuttons on this box. Both should light up.
- The rest of the gear is switched on from the front of the equipment racks. Switch on the TV monitor (12); opening the little flap at the bottom reveals the switch. Switch on the telescope focussing gear (3).
- Move the Cass. TV mirror to the IN position by typing I on the COORD control computer keyboard If it doesn't, you may need to reset the TTC connection.
This may not be the only problem which can occur here.
- On box (11) turn on the Image Intensifier, using the bottom red pushbutton marked IIT. Hold down the "OPEN" shutter button until the light goes out. This controls the shutter on the auxiliary wide field telescope which is sometimes needed for target acquisition.
- Science camera filter control is now via the cicada controller. Check the V and I filters on the drop-down "Filters" menu in the main Cicada window and make sure the display on the Filter control computer (16) follows suit.
- Next enter into the ST5 autoguider computer (14) utccdops. Then from the camera menu activate the camera cooling
- Turn on the dome position control in the box (9) above the main telescope control. The two digital read outs below will light, the left is the current position of the dome and the other displays the dome's target position. When first turned on the target position should be displaying "---" which means that the dome is not accepting positioning commands. Flicking the suspend button will toggle the state of the dome to accepting positioning commands. NB this is a quick way of stopping the dome in an emergency.
If there has been a power cut or some other problem the controller may need to be reset.
If the automatic position control is inoperative there is a manual override.
See the other notes regarding problems with the dome controller.
Zeroing coordinates and target selection
The control software on the telescope control computer (13) stores a number of target files each containing 500 objects. You can display the list of targets by pressing ALT-F4. To select a new file, enter (capital) O and the name of the file (no extension necessary). All the 2001-microlensing sources of interest are stored in the file P01.TAR; most other sources of interest are stored in the file COORD.TAR. You can scroll through the list using the arrow keys or PGUP and PGDOWN. Press ENTER once the desired source is found. Alternatively keys F3 and F4 enable you to move back and forth through the current file of source positions without listing the entire contents of the file. The RA and Dec of the source of interest will now be displayed in the middle of the 486 monitor. Before any observing is done it may be necessary to set the RA and Dec offsets. Centring an appropriate bright star with known position and setting the coordinates to that position does this. Note however, that the telescope tracking offsets are built in for targets with declinations between 0 degrees and 40 degrees S Hence, in this region the pointing is relatively precise and the computer will drive the telescope so that the target is well within the field of view of the Cass TV camera (~3x3 arcminutes). Hence it is often not necessary to zero on a bright star when observing in this region.
- While observing stars near the Galactic Bulge choose entry #2 or 3 (?) in the P01.TAR file, d SGR 2.7.
- Once the star has been selected, ensure that the TV mirror is in the "Infield" position (I should be highlighted on the control computer's display) and the strongest neutral density filter is in place ("ND 1000 on the small control box 18"). Now enter CTRL-D to initiate auto driving to the source.
Once the control computer has audibly announced its arrival at the star, press ALT-A to toggle ON the automatic dome positioning. The dome should now start to rotate into position.
- The star should appear close to the centre of the screen. Use the SET buttons on the control panel (15) to position the star at the position indicated by the green dot (marked aux) in the centre of the screen.
- For finer control select the Cass. image tube by pressing the far right hand switch on the TV screen control panel (12). d SGR 2.7 should be visible again after the brightness is adjusted.
- Centre the image at the red cross marked (Cass) on the TV screen (12). This centres the star on the CCD frame. Now zero the coordinates by typing ALT-O.
It may be necessary to re-zero the coordinates periodically throughout the night, particularly if you have difficulty locating a target field. It is not essential to go back to a bright star such as d SGR 2.7 each time, but this is the most foolproof method. When targeting bright stars, ensure that the (ND 1000 minimum light) filter is in place otherwise the phototube may be permanently damaged. If you drive to a bright star and it is not visible on the TV monitor, wait and make sure that the dome has caught up with the telescope before doing anything like going to weaker filters.
Now select your first target object and drive towards it using CTRL-D. Once there, wait until the dome has caught up (check the displays on the box above (8)). Move the Cass TV mirror to the Outfield position and step through the neutral density filters carefully one at a time using the filter control box (18). The caution is necessary in case a bright star is in the field. A star field should appear on the TV screen.
If a transparency overlay has been prepared for your object, place it over the TV monitor screen (12) and tweak the set and guide controls until the stars on the screen line up with the stars on the transparency. Once you are in the right position engage the Auxiliary Dec Drive (green pushbutton on (8)). (See the notes regarding intermittent problems with the aux. Dec. drive).
Before any images are taken, the telescope must be focussed.
- This is best done with no filters, so in the Cicada window under "Filters", select "C" (for Clear).
- Take a short exposure using Cicada, and select a subregion to focus on. This can be done by entering values into the dialog boxes in the main Cicada window, or by just clicking and dragging on the image window to create a box.
- You can now set Cicada to take images automatically by clicking on the "Expose no save" option and entering the number of images in the appropriate field. JG suggests a maximum of 20 images at a time since aborting the sequence may cause problems, including the program hanging and having to be "killed". Note that to display the multiple sub-images the minimum possible exposure time is 3s.
- Focus position is set by the voltage on the control box (3). The correct voltage depends mainly on the ambient temperature, normally measured at the spider (button 6 on box (10)). The ideal voltage-temperature relationship is somewhat variable but the most recent settings will normally be found plotted on a graph kept in the control room. From the spider temperature simply read off the appropriate voltage; JG reports that these voltages give quite good focus without much need for adjustment at present.
To adjust the level up or down set the value on the rotary encoders to say 500 or 1000. The level can be increased by setting the toggle switch to FWD or decreased with REV. Press the Start button to increment or decrement the voltage by the selected amount.
Once the appropriate level is set check the images to make sure the stars come out circular. (See the notes related to current problems with obtaining ideal focus).
An alternative way to check the focus is from a full image. This will of course have many more stars than the sub-field used in the procedure described above and so deviations from circularity may be more obvious.
- As the temperature falls gradually throughout the night you will periodically have to adjust the focus setting. Typically reducing the voltage by about 500 steps every couple of hours will do.
- First check all the settings on the ST5 autoguider computer (14). Go to TRACKING.
- Exposure Setup - should be 3s. Leave "Use Dark Frame" off for the moment.
- Pixel Setup - don't change.
- Relay Setup - Relay Polarities should both be "Reverse". The "Hysteresis" settings should all be zero.
- Correction Speeds - leave 1) and 2) on 0.8; set 3) and 4) to 1.4 or maybe 1.7.
- Max. Move - should be between 1 and 1.2 to 1.3.
- Tracking Control - Min Move is usually 250 - 400 ms; Dead Time should be zero and Move - don't touch !!
- Now go to CAMERA/SCOPE and choose CAMERA SETUP
- Anti-Blooming - should be Disabled.
- Dark Subtract - No at first.
- Camera Baseline - zero. (In poor conditions KMH recommends a setting of 1).
- Gain Exp. - MUST be 4x.
- Now go to GRAB
- Exposure Time - should be 3s.
- Dark Frame - Yes (for a first exposure).
To actually take the ST4 dark frame, press and hold in the SHUTTER button on (10) during the exposure. Start the dark frame by pressing ENTER (on the ST4 keyboard (14)).
- When the dark frame is done return to CAMERA/SCOPE and in CAMERA SETUP, change Dark Subtract to Yes and Camera Baseline to zero. Choose TRACKING and select GO.
- When the first frame appears, use the arrow keys to centre the moveable square on an isolated bright star, if possible. If no suitable stars are available press ESCAPE. Then change the ST4 mirror position with the UP/DOWN switch on (11). The transparent overlays mentioned above usually have a suggested ST5 mirror position (actually it's a voltage) written on them.
When you are satisfied press ENTER and autoguiding will start. The display will show the last 4 corrections in X (RA) and Y (dec) in pixels.
At last, you are ready to take a frame! It's a good idea to take a short exposure with the filter control set to I to make sure the target star is in the frame. Set the controls to "Expose no save" and take a short exposure. Once you're happy with this, click on the "Expose and save" option, set the "Object" field (you can choose from the drop-down menu), set the filename (check the naming convention pasted to the wall to the left of the Sparc 20), set the filter and exposure time and go! (Make sure you have reset the subregion options or you may get a ~600s exposure of the focus region).
Image acquisition and display
As soon as a frame is completed it will be displayed in the associated image window. You can vary the brightness and contrast by holding the right mouse button down and dragging the pointer across the image.
You can use the Graphical Interface Tool (with the unfortunate acronym of GIT) to get an estimate of the seeing. One pixel corresponds to 0.436".
Initiating an Automatic Sequence
Running a series of exposures with the same filter is easy. Just enter the number of exposures into the appropriate field in the main Cicada window and click on "Expose". The image number is automatically updated and added to the filename.
Life is more complicated if you want to change filters in the middle of the series. At this stage I am unaware of a way to do this.
What to do in case of cloud or rain
The environmental computer (6) display shows various meteorological parameters including the sky temperature as measured by the cloud sensor, graphed over the last couple of hours. For cloudless sky, this is around -20 degrees Celsius. If it clouds over, you will see this voltage increase and hit the top of the display. At this point you can wait around for it to clear or go to sleep. Switch the cloud alarm "On" and the level to -12 or so. This way, you can go and have a kip in the flat and when the cloud does clear and the level drops below -12, an alarm there will wake you. If this is driving you mad press the "Mute" button on the box to the left of the door (on the kitchen cupboards). Now you just have to hope that it will remain clear for long enough to get some observations in. If you do go to sleep it is essential that you close the dome doors in case it starts raining on the telescope while you are slumbering. With the dome shut you can cover the rain sensor too so that you do not get woken because it is raining rather than because the clouds have cleared!
If the rain detector goes off you will hear the dulcet tones of Tony Sprent warning you to close the dome. Get into the dome as quickly as possible and close the doors using the remote controller. If Tony's singing isn't quite your scene the "Mute" button will shut him off, at least temporarily. If the rain persists beyond a few spots, to prevent the alarm sounding continuously, try replacing the plastic cover until it clears again.
- Type ALT-A on the computer control computer to turn the autodome function off. Type ALT-D and enter 358 degrees for the dome parking position. Press return to send the dome on its way. Once the dome has arrived, flick the toggle switch on the dome controls to "Suspend". See the notes about the dome position controller.
- On the Sparc 20 choose "File" and "Exit Cicada to close the Cicada window.
- Turn the image intensifier (11) off. If possible wait for about a minute after this before turning on the dome lights. Shut the Guide Telescope Shutter on (11). Wait until the closed button lights up.
- Drive the telescope to Dec. = -42.50 degrees and an Hour Angle of zero. Elevation should be 90 degrees. NB there is usually a star in the target file called "home", "Home James" or something similar. Selecting this star sets the dec to -42.50 and if you set the RA equal to the LSMT by using the arrow keys to position the grey update box, this allows you to auto drive the telescope home, with only minor tweaking needed.
- Exit the telescope control software (13) off by typing F10. Turn the telescope power controls off. Press ESC to get out of the environmental monitor display (the keyboard is conveniently located under the desk). Choose "Quit" in the ST5 menu. Historical tradition would have you type PARK at the prompt of the ST5 computer before turning off, but I don't think this is still necessary. Perhaps better to be safe than sorry...
- Turn off the Filter control program by typing "Q" on computer 16 Now power down all the computers using the covered clear button on the auxiliary control box 11. Switch on the red dome lights and switch off the dome fans - both on the auxiliary control box
- Now turn down the current on the Peltier power supply (5) to 1.5 amps using the coarse voltage control.
- It is now safe to turn on the lights in the dome. Turn off the main fan and close the anteroom doors. Turn off the cooling pump at the power supply in the small RA drive room just inside the dome.
- Go up on the hoist and reverse all the switching on operations. Remember to leave ON the third switch from the top -otherwise you will have to restart the Leach controller next evening and that is a pain. As you close the petals, keep the left hand string taut. This will enable the petals to shut snugly.
- Replace the "top hat" on the telescope. Close the dome using the manual controls and switch the IR relay box off.
- Back in the control room, compress the nights images on the workstation into a single archive file using zip. E.g.
zip -2rT may1399.zip may1399/
This compresses the data and stores it in a zip file called may1399.zip. The "T" option tests the compression. rcp this file to bok, directory using
rcp may1999.zip bok:/data/data/new/data/data/new. Finally on bok type
This will send the data back to xray02 at the university. This normally goes by the microwave link but leave the modem link hooked up. This way bok can be accessed from the University if need be. If you do need to disable the modem link for whatever reason, type
- Finally go to the Planet homepage and enter your observing report.
Finally, as you leave, lock all the doors, re-arm the alarm, put the covers back on the rain sensor and cloud detector, not forgetting to turn the cloud detector off, and lock the compound gates.
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