C100/RetroCam Observing Procedures
Last update for this manual to be used on the C100 telescope on August
29th, 2012 (Nidia)
Contents
1. Initialize System
- Field of view is now: ˜ 3.4' arcmin
1.1 Instrument Control Computer: ARACHNE/CSP5
(Windows XP)
- User name: cspuser
- Password:
- Double click on the RetroCam icon.
- A window called Database Initialization pops up:
- Check Camera, Telescope, Guider, and
FilterWheel ar all ONLNE.
- TemperatureControl should be OFF.
- Type in observer's name in Observer.
- Then click OK
- A window called RetroCam-Control pops up.
- Go to the Modules tab and open the TeleGUI and,
Display.
Once you open TeleGUI the UT time updates.
- In Telescope Control window go to the File tab and
open SkyMap, Airmass, and ObjectList.
- In RetroCam-Control window go to the Option tab and
select DataPath.
- In the window that pops up write the directory in csp4 where the data
will be directed. Use the CSP naming convention.
We are currently using Rigel instead of csp4 as Data Reduction computer,
thus 'datapath' has to be defined accordingly.
Check on next section (1.2.1).
1.2 Data Reduction Computer (csp4 or Rigel)
- 1.2.1 Rigel
- User name: retrocam
- Password: check on control room or ask the technical staff
- After logging in, type: 'goiraf' on a terminal in Rigel. This will open an xgterm and a DS9 window, and start an IRAF session.
- The quick-look reduction package will load while IRAF starts.
- On a terminal in Rigel type 'cd /Volumes/Data_Rigel/'
- Create the working directory for the night: mkdir 20111107_08 (for example)
- Specify the working directory under 'Data-Path' on the RetroCam control window in CSP5: \\rigel\Data_Rigel\20111107_08
- If desired, you can run RetroCam from Rigel using VNC (so you don't need to type into CSP5). Ask the technical staff for help if you are interested in trying this option.
- 1.2.2 CSP4
- User name: cspuser
- Password: available on the telescope
- Open a terminal (you can use the icon in the task bar).
- Create a directory for the night and make it writable by
csp5. For the example above:
> cd /data
> mkdir 20050906_07
> chmod 777 20050906_07
- Open an IRAF window by clicking on the "drawer" icon in
the task bar.
Or in the terminal, type:
> cd
> xgterm -sb -e cl &
- In the IRAF terminal, go to the data directory, e.g.:
cl> cd /data/20050906_07
- See the use of observing scripts in Section 4 below.
- Open DS9 from the Linux terminal:
> ds9 &
1.3 Check UT time
- Check the current UT time (e.g, the USNO web page).
- If the Universal Time at the TCC-Guider PC differs from
this more than a few seconds, ask the telescope operator or the
daytime technitian to try fixing it.
- It is very important that you check
the UT and ST are right (within some seconds) in the
Retrocam-Control window in csp5.
- If this is not the case, restart the RetroCam control program in
csp5 as described in Section 1.1.
- Once you re-open the TeleGUI module the UT should update
and be close to the time in the TCC-Guider PC.
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2. Calibrations and Telescope Setup
2.1 Dome Flats
- Ask the operator to request the telescope to be positioned to the
white spot for domeflat calibrations
- In Retrocam-Control window set:
- Exptime = 5
- Readmode = Double
- ObjType = dflat
- Loops = 15
- Object = Domeflat (no space)
- Turn ON quartz light.Max voltage is 480.
This way you should get about 12,000 ADU on average.
- Go to the dome and check both the telescope and the quartz light
points to the white screen, and that no shadows are cast on the screen.
- In Retrocam-Control window select a filter and click the
Go button to start a loop of flats.
- When done, turn OFF quartz light.
- Click Go again to get "lamp-off" flats.
- Change filter and lamp level, and repeat the two previous steps.
- When the sequence of dome flats is complete, check that the quartz
lamp is OFF.
2.2 Sky Flats
- Ask the operator to go to an empty field.
Beware that some of these fields are dark clouds in
the Milky Way which contain plenty of stars in the NIR.
- In Telescope Control window set dy = 10 (10 arcsec
steps).
- In RetroCam-Control window set:
- Exptime = 5
- Readmode = Double
- ObjType = tflat
- Filter = Hc
- Loops = 2
- Object = Skyflat (no space)
- Start a test exposure with Go. Repeat until you have gone down
below 20,000 ADU. Make sure that average counts are indeed
going dwon between subsequent integrations. If not, the chip is
saturating.
- Change Exptime = 5.
- Reset counter in Filename to first unused number you had before the
tests.
- Push Go to start the first flat.
- Push the N or S buttons in Telescope Control
window between exposures.
- Alternatively, you can do the offsets by running a dither macro:
In RetroCam-Control window press Dither and select
- Dither-Pattern = rot-5
- Dither-Step = 10
- Guider = none
You can change the exposure time while the telescope offsets between integrations.
- Take at least five (5) images.
- Change Filter to Yc and repeat the procedure above.
- Take at least 5 images with 8,000 to 20,000 ADU, and offsetting
the telescope between them.
- Finally, go to Filter = Jo and move the telescope 2 or 3
hours West.
- Try to get 5 images in Jo with high counts and few stars.
2.3 Telescope Zero-Point (CSET)
- Ask the operator to point to a bright star for the zero-point
- In RetroCam-Control window set:
- Exptime = 3
- Readmode = Double
- ObjType = test
- Filter = Yc
- Loops = 1
- Object = Test
- Take an image with Go.
- In the Display window click on the center of the bright
star.
- In the same window click on Center Telescope.
- In Telescope Control window click on the 0,0
button.
The telescope will now center the bright star.
- Ask the operator to do the 'CSET'.
2.4 Telescope Focus
- Same focus value will work for Y and H filters, while
an offset of +0.15 units is needed for J. As an example,
for a temperature about 8-9 degrees, the focus is near 43.00 for
Y and H, and 45.15 for J.
- If the focus is fairly good, ask te operator to start a sequence,
take a single 10sec image, and wait for the operator to change the
focus value
- Exptime = 10
- Filter = Yc
- Loops = 1
- ObjType = test
- Object = Test,
- Display the images in csp4 and run imexamine and its
commands 'r' and 'e' to see the size and shape of point-like sources.
- Tell the operator what the best focus was so that he does an fset.
2.5 Darks
Darks may be taken in the afternoon if the temperature is not much
higher than the expected one for the night.
Else, they should be taken
in the morning, or during the night in case no object can be observed.
Darks should be taken every night with each exposure
time used that night.
Therefore, you may need to add darks in the morning, once you know
which exposure times you have used.
Note that this includes all the exposure times
used for twilight flats.
- In the RetroCam-Control window select:
- Readmode = Double
- ObjType = dark
- Filter = dk
- Loops = 15
- Object = Dark
- Set one of the required exposure times in ExpTime.
- Click Go to start taking the darks.
- Repeat with every required ExpTime.
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3. Observing
3.1 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 is now working for sending the target
coordinates to the TCS.
- Select an SN and send it for the operator to move the telescope
to the target.
- 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. These offsets will be applied in arcseconds;
the image scale is 0.201 arcsecs per pixel.
- 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.
- Start a dither sequence by pressing Execute in the
RetroCam-Control window.
- When the sequence is done, you may need to offset the
telescope as indicated in the Beam Switch column of the target list. Or as
from now on, sky images shall need to be taken, for this do an
offset so that the galaxy if OFF the field of view.
- 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 J.
- Make use of the quick-processing scripts described in
Section 4 below to check the quality of the data
and perform quick photometry.
3.2 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.
- Select an STD. from the object list and SendTo the TCS, and tell
the operator to 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. This offset should be now
smaller. Try with smaller offsets and cross-check.
- 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 from Y-H to J.
3.3 Guiding
- Guiding is now done automatically by the telescope. Once you're
pointing to your target, when selecting the macro on
the Dither, choose guider=auto.
Then the operator will search for a guiding star and put it into the
guiding box and shall start guiding, and when ready, the
observations can start
- A new improved SkyMap is ready. A link shall be added when the LCO web
site is updated with the info and snapshots.
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4. 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.
- rcmosaic:
This script allows to run all the necessary steps
to produce a quick staked image at once.
- 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
- Alternatively, just type: rcmosaic 10 18 and follow the instructions that
will be displayed.
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5. Copying Data to a CSP Machine
At the end of the night, you must transfer data from Rigel to
the /raw directory in csp2.
From a terminal in Rigel, cd to /Volumes/Data_Rigel
and then type:
scp -r name__of_the_night user@csp2:/raw/DUP_RC_name_of_the_night
where 'name_of_the_night' is, for exapmle, 20120828_29
and 'user' is your login name on csp2 computer.
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6. Before You Go to Bed
6.1 Fill in CSP Night Report and SN Logs
- Fill in the CSP
Night Report. (User name and password required.
- 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.
- 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.
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7. 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.