C40/RetroCam Observing Procedures

Contents


1. Initialize System

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2. Activate Telescope

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3. Calibrations and Telescope Setup

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4. Observing

    4.1 Supernovae

    • Check the current list of targets and exposure times for RetroCam.
    • Check the target RA order and priorities. Also look at the finding charts and the airmass plot, if available.
    • In the Object List window go to File and Load.
    • Select the file csp.objects and click Open.
    • The current list of SNe being followed is displayed.
    • You can use the buttons to Add, Edit, or Remove an object.
    • Remember to save your changes or else you'll lose them when you close the application.
    • The Preview button shows the situation of the selected target in the Airmass and the Skymap windows without having to point the telescope to the object.
    • The SendTo button has no effect here.
    • In the TCC-Guider PC type 'MP 2000.0'.
    • Select an SN and, in the TCC-Guider PC, type its 'RA hh mm ss.s' and 'DEC dd mm ss.s'. Then type 'SLEW'.
    • When the slew is complete, press the Get button in the Telescope Control window in order to have the right coordinates RA and DEC written in the image headers.
    • To check the pointing, in the RetroCam-Control window set:
      • Filter = Yc or Jo
      • Exptime = 10
      • Loop = 1
      • ObjType = astro
      • Object = SNYYYYaa   (no spaces; YYYYaa is the IAUC or temporary SN ID).
    • Take a test image by clicking on Go.
    • Check that the field is the one shown in the finding chart.
    • Remember that the coordinates in NIR not necessarily match those given in the yellow table.
    • If you need to correct the pointing, use the dx and dy offsets and the directions panel in the Telescope Control window.
    • The upper-left (NE) quadrant should be avoided because it contains several dead spots.
    • Also check that the SN and some of the field stars will end up having decent counts and not saturating with the exposure time to be used.
    • Reset the Filename counter to the value previous to the test, and set Exptime, Loops, and Macro as indicated in the target list of the night.
    • To define the Macro, press Dither and select the options of Dither-Step, Dither-Pattern, and Guider. Make sure you select Guider = auto.
    • Set Readmode = Quadruple for filters Yc and Jo, and Readmode = Double for filter Hc.
    • Choose a suitable guide star and start guiding. See instructions Section 4.3.
    • Start a dither sequence by pressing Execute in the RetroCam-Control window.
    • Keep an eye on the guider screen and check that the guide star is not lost (this may happen a couple of times in the night.) There is no alarm when this happens.
    • When the sequence is done, you may need to offset the telescope as indicated in the Beam Switch column of the target list. See instructions on how to recover the same guide star in Section 4.3.
    • Repeat this procedure with every requested filter.
    • Keep in mind that each filter may require a different dither macro.
    • Also remember to apply the focus offset when you change from/to Hc.
    • Make use of the quick-processing scripts described in Section 5 below to check the quality of the data and perform quick photometry.

    4.2 Standard Stars

    • If the night is photometric, observe at least 3 or 4 Persson Standard stars.
    • In the Object List window go to File and Load.
    • Select the file persson.objects and click Open.
    • The list of Persson standards is displayed.
    • Pick a star from this list with J magnitude between 10.8 and 12.0.
    • Make sure the standard stars you observe in one night cover a wide airmass range between 1 and 2.5.
    • In TCC-Guider PC type in the 'RA hh mm ss.s' and 'DEC dd mm ss.s' and then 'SLEW'.
    • When the slew is complete, press the Get button in the Telescope Control window in order to have the right coordinates RA and DEC written in the image headers.
    • In the RetroCam-Control window select:
      • Exptime between 5 and 10
      • Readmode = Double
      • ObjType = standard
      • Loops = 1
      • Object = SJ####   (no space, #### is the number of the standard)
    • Take a test exposure with Go and check the field and exposure time.
    • You may need to move the star off the quadrant divisions. If so, in Telescope Control set dx and dy to something like 50 and move diagonally in the chip.
    • Avoid the upper-left (NE) quadrant. It cointains spots of dead pixels.
    • If the star is too bright, you may need to defocus slightly the telescope so that it doesn't saturate.
    • In the RetroCam-Control window select the macro by clicking on the Dither button. Then select:
      • Dither-Step = 15''
      • Dither-Pattern = rot-5
      • Guider = none
    • No guiding is required.
    • Launch a dither sequence by clicking on the Execute button.
    • Change filter and repeat the previous step until you have done Yc, Jo and Hc.
    • Remember to apply the focus offset when changing to/from Hc.

    4.3 Using the Guider

    • Once you have gone to the SN field, you need to choose a guide star.
    • Go to the SkyMap window and select a star of mag between 10 and 12 in the guider field (a blue rectangle above the square chip field.)
    • Avoid the bottom region of the guider field because this may cause vignetting on the chip.
    • Double click on the star with the right-hand mouse button. This will write offsets in the Guider Control window.
    • Click on Move to move the guider to the selected star.
    • You should in principle see the star in the Guider screen. However, this is usually not the case. Move the guider NW several times by clicking on the corresponding button in the Guider Control window.
    • Once the star appears, place it in the upper part of the guider screen.
    • Check the guider camera focus and adjust it if necessary using the switch on the light blue rack.
    • In TCC-Guider PC press the Guider button to activate the guider camera monitor.
    • Move the guider box using the arrow keys and put it on the guide star. You can select two "speed" modes for these movements by pressing the Delete and Insert keys.
    • Check the count level mx in the guider camera monitor is below 250 (saturation).
    • With the star inside the box, press F3 in the TCC-Guider PC to start guiding. Now you are ready for launching a dither macro.
    • When the telescope is offset to a new position during the dither sequence the guiding won't be stopped. There will be a delay of 4 seconds before the start of the next integration while the guider camera will try to follow the telescope and bring the guide star back in the guider box automatically. This is successful in more than 95% of the cases, and you won't have to touch anything.
    • If the guider fails to find the star instead, you can do the following:
      • pause the integration by clicking on Pause in the Telescope Control window until the star enters the box on its own.
      • place the star in the box either by moving the camera using the Keypad in the Guider Control window in csp5, or by moving the box using the arrows in the TCC-Guider PC keyboard.
    • If the object is close to the pole (DEC < -80 deg), you will have to pause almost after every integration.
    • When you have to do a Beam Switch on an object, you can recover the same guide star you have been using by moving the guider according to the telescope movement. This way you won't need to stop guiding.
      • If, for instance, you did a telescope offset of dy = 180 arcsec to the N, in the Guider Control window enter Xoff = 0 and Yoff = -180, and click on Move right after you move the telescope. This will move the guider roughly back to the guide star. You will need to move slightly the guider box to place the star inside it.
    • Before you move the telescope to a new object you will have to stop guiding by pressing F1 in the TCC-Guider PC.
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5. Quick-Processing IRAF Scripts

  • A series of IRAF scripts are available in csp4 to help the observations.
  • The scripts are loaded automatically when you start IRAF. The task definitions are given in the 'loginuser.cl' file in ~/iraf/.
  • The script files themselves sit in ~/iraf/retro_quick/.
  • The following tasks are available:
    • dis:
      Displays an image without having to type in the whole name.
      Usage:    cl>  dis  num   loo
      where 'num' is the frame number, and loo is the loop number.
    • disi:
      The same as above but it starts imexamine.
      Usage:    cl>  disi  num   loo
    • dp:
      Displays the difference between two "_001" frames.
      Usage:    cl>  dp  num1   num2
      where 'num1' and 'num2' are the frame numbers of the images to be subtracted.
    • pdiffi:
      Displays the difference between any loop of two frames and starts imexamine.
      Usage:    cl>  pdiffi  num1  num2
      by default, it subtracts loops "_001" of both frames.
      You can edit the optional parameters 'l1' and 'l2' to use other loops.
    • avgo:
      Displays the difference of two frames after averaging all the loops in each one.
      Usage:    cl>  avgo  num1  num2
      You can modify the optional parameter 'scl' to change the scaling factor to be applied before subtraction --- scl = "mode" is the default.
    • sky_stats:
      Shows the median and mean sky level for a range of frames. Useful to check flats.
      Usage:    cl>  sky_stats  num1  num2
      where 'num1' and 'num2' give the range of frames to analyze.
    • p_fid:
      Mark a fiducial star used to align dithered images.
      Usage:    cl>  p_fid  r  num1  num2  aut/man
      where 'num1' and 'num2' give the range of frames in a sequence. Options 'aut' or 'man' allow to make the program select a star, or the user to mark it. The task will write the star position in the headers of frame num1.
    • p_fx_asecs:
      Correct the RA and DEC offsets between frames that are written in the header keywords ASECS and DSECS.
      Usage:    cl>  p_fx_asecs  r  num1  num2
      where 'num1' and 'num2' give the range of frames in a dither sequence. The user will be prompted to mark the same star in all frames (after averaging the loops). r_quick will usually fail if this is not done in advance.
    • p_mimdel:
      Delete a range of frames of some kind.
      Usage:    cl>  p_mimdel  pre  num1  num2
      where 'pre' is a frame prefix ('icr' for loop-combined, 'isx' for sky-subtracted, etc.), and 'num1' and 'num2' give the range of frames in a dither sequence. Since p_fx_asecs fixes the headers of 'irr' frames only, you will need to delete the 'icr' frames before running r_quick, in order to get the right offsets.
    • r_quick:
      Produce a quick and dirty stack of a range of frames.
      Usage:    cl>  r_quick  num1  num2
      It produces a sky by averaging the frames. It asks the user to mark a few stars with 'a' in imexamine. It may fail if the dither steps are too large (>30''), or if the guider star got lost.
  • To make a fast combination of a dither sequence:
    For example, a sequence of frames 10 to 18.
    • p_fid r 10 18 aut
    • p_fx_asecs r 10 18
    • p_mimdel icr 10 18
    • r_quick 10 18
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6. Copying Data to a CSP Machine

  • At the end of the night, tranfer the data from csp4 to csp3.
  • Open a terminal window in csp4.
  • Go to the directory with the data of the night, e.g.:
    > cd /data/20050906_07
  • Do a secure copy to csp3 giving your user name in that computer, e.g:
    > scp -r ../20050906_07 username@csp3:/data/ir
  • You will be asked for your password in csp3.
  • The link should be fast enough to copy more than 100 MB per minute.
  • While the secure copy runs, you can proceed to the next item.
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7. Closing the Telescope

  • Turn OFF power of guiding camera in lightblue rack.
  • Move telescope to HA 2:30 East to secure that nothing falls on mirror while closing dome shutter.
  • 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.
  • Fill out Night Reports and SN Logs (see below)
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8. Before You Go to Bed

    8.1 Fill in Night Report and SN Logs

    • Fill in the LCO Night Report.
    • Add a line requesting the staff to switch to the CCD camera, if applicable.
    • To make sure the request is heard, stick a note on the telescope console directed to the daytime technicians so that they see it in the morning.
    • Fill in the CSP Night Report. (User name and password required. If you are not a CSP member, please be so kind to send an e-mail to Gastón Folatelli, gfolatelli@lco.cl, instead.)
    • In the "Night time report" field, inform about objects observed and calibrations taken. Give details about weather conditions and describe technical problems, if any.
    • Fill in the CSP SN Log of the night. (User name and password required.)
    • This form allows you to input all the SNe of the night at once in a comma-separated list.
    • The SN names can be introduced in a variety of formats. The program then completes the names in the standard form.
    • In the Filters field you can input a generic 'YJH'.
    • Click on Submit and an editable list will appear.
    • Modify the fields according to what you observed in the night.
    • In particular, check the Filters and Weather fields because these may change from SN to SN.
    • The rest of the fields will generally have the same information for all the SNe.
    • Click on Submit to send the logs to the database.

    8.2 Burn two DVDs

    • To burn the data to DVD you have three alternatives:

      1- Use growisofs in csp4 (Linux).
      • Follow these instructions by David Murphy.
      • Put only the irr_*.fits in a subdirectory. E.g.:
        > mkdir todvd
        > mv irr_*.fits todvd/
      • Check the size is less than 4.3 Gb:
        > du -h todvd
      • In the unlikely case that the data are more than this value, separate them in two directories and burn two DVDs.
      • Burn:
        > growisofs -Z /dev/cdrom -R -J -apple todvd
      • Do not run heavy processes (e.g., image processing) while burning. Other light processes like mozilla, editors, etc are not a problem.
      • Burning takes about 15 min for a whole DVD (4.3 Gb), at speed=4x.
      • When done, the DVD is ejected and loaded again.
      • Take the DVD from the drive by pushing the eject button.

      2- Use RecordNow DX in csp5 (Windows).
      • Close all other applications. (Yes, do you like Windows...?)
      • Double click on the RecordNowDX icon on the desktop.
      • Choose the option Make a Data Disc.
      • In the following window click Next.
      • Click Add Files and Folders.
      • Click the drop down arrow in Look in.
      • Select data on 'Linux Samba Server ...'.
      • Select only the irr_*.fits files with drag and drop.
      • Check the total size of the stuff to be burnt is less than 4.3 Gb.
      • In the unlikely case that the data are more than this value, leave some files to a second DVD.
      • Click Next. You'll be warned not to run other applications. Click ok.
      • The DVD burning will start right away!
      • Don't run other processes while burning.
      • This program by default verifies the written data after burning. This is a nice feature but it takes twice the time.
      • When done, the DVD will be ejected.

      3- Use K3b in csp4 (Linux):
      • Open K3b either from a terminal:
        > k3b &
        or by clicking on the icon at the task bar.
      • Select the option Create Data DVD Project.
      • In the upper half of the window select the files to be burnt. Use the left-hand mouse button in combination with the Shift and Ctrl keys.
      • Select irr_*.fits files and drop them in the lower half of the window.
      • Check the total size of the stuff to be burnt is lees than 4.3 Gb.
      • In the unlikely case that the data are more than this value, leave some files to a second DVD.
      • Click on Burn.
      • Under the Writing tab, select:
        • Speed = 2x
        • On the fly
        • Verify written data
      • At the Volume Desc tab you may input a Volume name for the DVD (e.g.: '20050906_07 - RAW'.)
      • Under the Filesystem tab, select:
        • Generate Rock Ridge extensions
        • Generate Joliet extensions
      • Click the Burn button to start recording.
      • After the data are written and verifed the DVD will be ejected.

    • Label both DVDs with:
      C40'' + RetroCam
      Raw data
      Observer's name
      Directory name (e.g. "20050914_15/")
      Total size
      Copy number (1 or 2)
      DVD number, if there is more than one for the night.
    • Put the DVDs in plastic cases and send one of them to Gastón at El Pino along with the log sheets.
    • Keep the other DVD in Nidia's office at the ASB.
    • Plastic cases can be found in Nidia's office.
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9. Linearity Tests (Only for Cloudy Nights)

  • Wait until it is dark outside and close the dome.
  • Turn OFF the incandescent dome lights from the console.
  • In TCC-Guider PC, type 'DOMEFLAT' to point the telescope to the white screen.
  • In RetroCam-Control window set:
    • Filter = Yc
    • Readmode = Double
    • ObjType = dflat
    • Loops = 1
    • Object = Linearity
  • Turn ON the quartz light from the grey box over light blue rack and adjust voltage so that you get 2000 ADU in 10 s (550 V should be OK).
  • Take the following series of exposures, changing ExpTime each time to the values below, and pressing Go.
    ExpTime values: 10, 3, 10, 7, 10, 15, 10, 20, 10, 30, 10, 45, 10, 60, 10, 75, 10, 90, 10, 105, 10, 120, 10, 135, 10, 150, 10, 165, 10, 180, 10, 195, 10, 210, 10, 225, 10, 240, 10, 255, 10.
  • You must reach about 48,000 ADU in 255 s.
  • Turn the quartz light OFF and take Darks at each Exptime above, using Loops = 1.
    In RetroCam-Control window set:
    • Filter = dk
    • Readmode = Quadruple
    • ObjType = dark
    • Loops = 1
    • Object = Dark
  • Only ONE dark at 10s is needed.