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C40/CCD Observing Procedures

IMPORTANT: START BY CHECKING THAT WE HAVE THE RIGHT FILTERS IN THE CAMERA: LC-3013 (B), LC-9844 (V), u', g', r', i'

 

  • Initializing systems
  • NOTE: everytime there is an instrument change, e.i., SITe3-RetroCam and vice versa, make sure the TCS SWITCH BOX is set to CCD when SITe3 is to be used.


This switch box is located next to the DATA PC (left)

  • 1. Update UT in DATA PC (located in light blue rack)
    • Please update the UT Time in the data PC. For this, you need to open
      a terminal on Puma. And telnet to the data PC, in this way:
    • Type 'date yyyymmddhhmm.ss'
    • Type 'date' (to confirm entry)
    • Type 'exit' (to exit from data pc)

  • 2. Update UT in TCS computer
    • In TCS computer you need to type 'UT hh mm ss' followed by RETURN
    • Check in the screen that the UT was properly changed

  • 3. Start CCD Control Window in Data Acquisition Computer (Puma)
    • login: obs40
    • password: check label on monitor
    • cd /DATA
    • mkdir 20020914_15 (e.g.)
    • cd 20020914_15
    • cp ../filter.names ./subraster/ccd.macros (or edit file with 6 filter names using "UBVRI" IDs); filter.names file should always bear six lines
    • ccd (opens CCD control window)
    • before the CCD control window appears you have to select 5 parameters from the menu:
      • Curtain
      • Site3
      • 32 SN value -> default value: 16
      • LCO-40
      • LCO-40
    • On the CCD control window select Gain 3
    • Open an IRAF window and change to the recently created directory (20020914_15)
    • Open DS9 window

  • 4. Activate Telescope
    • Turn console ON (rotate key)
    • Turn Power ON
    • Check that platform is clear and in TCC-Guider PC, type 'COVER' (telescope will slew south)
    • Go to the platform, raise platform, and remove the telescope cover
    • Lower platform

  • 5. Initiate Guider
    • Bring telescope to the zenith
    • From any window in Puma computer type command 'rgdr', which will open guider window
    • A new window will appear where you need to enter X and Y values accordingly (next to GOTO box)
    • Click GOTO and SETCENTER
    • Click PARK before taking calibrations
    NOTE: TELESCOPE SHOULD ALWAYS BE AT THE PARK POSITION FOR TAKING CALIBRATIONS AND FOR THE OBSEVATIONS
Calibrations
  • Turn OFF platform lights from console
  • Set focus value, upward, downward before taking flats
  • In TCC-Guider PC, type 'DOMEFLAT' to slew telescope to white screen
  • Turn ON quartz light from grey box over lightblue rack and adjust voltage to ~865 units (check with one integration in g 30s.
  • Check that lamps are pointing to the white screen and make sure that the illumination of the screen is truly uniform
  • In 'ccd' window set exposure time, filter, Loop to 7, Imtype to flat, and object to "Domeflat"
  • Exposure times:
    • B: 120 sec (9000 cts/pixel)
    • V: 30 sec (11000 cts/pixel)
  • Start sequence with START botton
  • It is possible to take the whole sequence of flats with one click. You need to have the file ccd.macros in the current directory.
    Type "doflat" in the MACRO box in the 'ccd' window and click "RUN MACRO".
  • When the sequence of flats is complete turn OFF quartz lamp on grey box
  • In 'ccd' window set exposure time to 0, Loop to 10, Imtype to zero, and object to "Bias"
  • Start sequence with START botton
Opening dome, and Preparing Telescope Control System (TCS)
    Before sunset you must do the following:

  • Turn ON fans in adjacent room (turn ON switch and set reostat near maximum value)
  • Push OBTURADOR on console to open shutter
  • Push PANTALLA on console to lower windscreen
  • Push ASENCION RECTA on console to turn ON tracking
  • In TCC-Guider PC, type 'DOME AUTO' to activate dome rotation
  • In TCC-Guider PC, type 'TP' to activate telescope pointing model (this is not necessary if the model is
    already activated since this is a toggle key;
    check on the TCS screen if the 'TP' flag is on, TP should be highlighted in green, TP)
  • In TCC-Guider PC, type 'MP 2007.5' to set the coordinate epoch (for pointing to bright star ONLY)
  • Turn on power of guiding camera in lightblue rack, and turn OFF 'bright' button
Skyflats
    At sunset you must begin taking sky flats:

  • SLEW telescope to the East
  • In TCC-Guider PC, type DBB 20, (set step to 20 arcsec)
  • In 'ccd' window set exptime to 3 (minimum), choose u' filter, set Imtype to flat, and object to "Sky Flat"
  • Start exposure with START botton
  • After completing the exposure in TCC-Guider PC, type SS to slew telescope south by 20 arcsec
  • Take 5 frames per filter with exposures longer than 5 sec and never exceeding 23000 adu.
Telescope Zero-Point
  • Deselect the subraster
  • In TCC-Guider PC, type RA hh mm ss.ss, and DEC dd mm ss (ccordinates of a bright star near the zenith)
  • In TCC-Guider PC, use the SLEW command to slew the telescope to the desired position
  • Turn subraster ON and take a new exposure to check that the offset worked fine
  • In TCC-Guider PC, type CSET to zero-point the telescope
  • You should see the bright star in the guider field of view by clickig on the RGDR CENTERFIELD; then for start observing click PARK
  • If the star is too far from the cross, use the paddle to bring the star to the center, and click SETCENTER
  • Focus guider camera, there is a swith labeled as Focus + - above the CCD electonics unit
Focusing the Telescope
  • Point to a 10th magnitude star
  • Click PARK in 'gdr' window
  • In 'ccd' window click OFF next to subraster (the full CCD will be read), set exptime to 10, Loop to 7, filter=V
  • Use focus bottons to set focus reading to 0 in box located above console (always moving upward)
  • In 'ccd' window click FOCUS to start first exposure of 10 seconds
  • Once the first exposure is complete increase focus by .5 units and click on FOCUS again.
  • Complete sequence of 7 exposures
  • In IRAF window display image 'focus'
  • On console set the focus to the best value
  • Don't forget to enable the subraster in the 'ccd' window (click ON)
  • Focus Offsets are provided in the next table:

    V 0.00
    B +0.08




Using the guider
  • In 'gdr' window you need to enter X and Y values, depending on the Subraster selected (next to GOTO box)
  • Click GOTO (wait a few seconds) and click SETCENTER
  • Use TCC to SLEW telescope to your target
  • In 'gdr' window click PARK to remove guider from the field of view of the CCD
  • In 'gdr' window turn ON the KEYPAD and use arrows to move the guider around until you find a guiding star
  • In "GUIDER" enter the parameters of the camera (check sheet)
  • On the TCS keyboard you can use the arrows to move the white box and put it on the guiding star
    (if the box doesn't move type 'xy5')
  • On the TCS use F3 to activate guider
  • On the TCS use F1 to de-activate guider

Observing
  • In 'ccd' window set Imtype to object, select exptime, and filter
  • Don't forget to apply focus offset for the selected filter
    • B: +0.08
    • V: 0.00
  • Turn ON guider (F3)
  • In 'ccd' window use START to begin exposure
  • Turn OFF guider (F1)
Closing the Telescope
  • Turn OFF power of guiding camera in lightblue rack
  • Push OBTURADOR on console to close shutter
  • Push PANTALLA on console to raise windscreen
  • Push ASENCION RECTA on console to turn OFF tracking
  • In TCC-Guider PC, type 'DOME IDLE' to de-activate dome rotation
  • In TCC-Guider PC, type 'DOME PARK' to park dome to the south
  • In TCC-Guider PC, type 'COVER' (telescope will slew south)
  • Go to the platform, raise platform, and put on the telescope cover
  • Lower platform
  • Turn OFF fans in adjacent room (turn OFF switch and set reostat to zero)
  • In TCC-Guider PC, type 'ZENITH' (telescope will slew to the zenith)
  • Turn Power OFF on console
  • Turn console OFF (rotate key)
  • Turn OFF monitors in control room
  • In 'gdr' window click CENTERFIELD
  • Fill out Night Report here
  • You can go party now
Shutter timing and linearity tests (alternative program for cloudy nights)
    If you cannot open the dome because it is overcast, it would useful if you could carry out
    shutter timing and linearity tests following the following instructions:

  • Shutter test
    • Wait until the sky is dark and close the dome.
    • Turn off the incandescent lights from the console.
    • Point the telescope to the zenith.
    • Set the subraster to [1310:1510,501:701]
    • Turn on the quartz lights from until you get about 10 kcounts/pix in 30 sec. Then use the MULTIPLE
      option to get a 10x3sec exposures, followed by a single 30sec expsoure. Repeat this procedure until
      you have about 10 pairs of long-short images.
  • Linearity test
    • Wait until the sky is dark and close the dome.
    • Turn off the incandescent lights from the console.
    • Point the telescope to the zenith
    • Set the subraster to [1310:1510,501:701]
    • Turn on the quartz lights from the console until you get 100 counts/pixel (above the bias which is ~600 counts/pix) in 8 seconds.
      Then take exposures of 4, 8, 16, 8, 24, 8, 32, 8, 48, 8, 64, 8, 80, 8, 96, 8, 120, 8, 144, 8, 180, 8, 240, 8, 320, 8, 400, 8, 500, 8, 600,
      8, 700, 8, 800, 8, 1000, 8, 1200, 8, 1300, 8, 1400, 8, 1500, 8, 1600, 8, 1700, 8, 1800, 8. Feel free to stop this sequence when
      you reach 24 kcounts/pix. The 8 sec exposures are used to control the illumination variations. With the task imstat you can
      check the illumination level in the 8-sec exposures. If you notice large (> 3%) variations please get another sequence.
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