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NotesforObservers

Timestamp:: Feb 22, 2016 12:41:20 PM (8 years ago)
Author:: Arjun Dey
Comment:: --

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PublicPages/MayallZbandLegacy/NotesforObservers

-                      v104
+                      v105
 Prolonged exposure can damage and even destroy the devices. The following rules are in effect:
 . Operation on sky is restricted to between 12 deg twilights.
+. Operation on sky is restricted to between 10 deg twilights.
 . Operation is restricted to when OAs or other NOAO technical/scientific staff are present
 . The cameras and MOSAIC software should be shut down when observing / NOAO personnel are not present
 …
 Then, in one of the NOCS xterm windows, type: "nocs set project"
 = [6] Take a test image to ensure system is working =
+= [6] Take a test Zero image to ensure system is working =
 Check that all is well by taking a test zero exposure.
 …
 = [8] Just before observing =
+. It is best to start things up after sunset and to be ready to start observing before the 10 deg twilight mark.
+deg twilight times for KPNO are listed here:
+Before 10 deg twilight, you can do all the steps in [8] (i.e., this one)
 . Start the mayall-idl:1 VNC session.
 …
 }}}
+= [9] Observe - start of night =
+''No on-sky observations are permitted before 12 deg twilight.''
+. Take a zero image to ensure everything is working
+. Set the focus to some approximate value based on the Truss temperature and the formula:
+. Take a zero image to ensure everything is working. Once the image has been written, use the
+IRAF window and run mscstat <filename> to make sure the system came up OK. See step [6] above.
+. Set the focus to some approximate value based on the Truss temperature and the formula:
 - Focus(zd) = -8400+(1.4-Ttruss)x110
 where Ttruss is in deg C
+. At start of night, check telescope pointing and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane).  When taking the image of the bright star, make sure to create an OBJECT script with NGUI (not a TEST, because MOSSTAT will ignore it), zd filter, 1 - 5 sec exposure.  Watch for MOSSTAT to process the image and report the RA, Dec offsets.  If mosstat fails, it could be because (a) the telescope is mis-pointed, (b) the telescope is out of focus (set the focus approx using the formula above and try again). Once you are able to determine offsets,  give these offsets to the OA with **opposite** sign.  That is, if mosstat reads "RA,Dec offsets = -15.34, 18.32", then you need to provide the OA with the offsets of +15,-18 to zero the telescope coordinates. You can take another OBJECT frame if you want to check to make sure the offset went in the right direction.
+. Move to the beginning of the first MzLS tile position.  What position is that, you ask?  One way to find out is to run mosbot.py (see step 5 below), and look for RA, DEC in expose-1.sh in the exec/mosbot/ directory.  Tell these coordinates to the OA to move the telescope. Another way is to look at teh first entry in the ~/obsbot/pass1.json file on the mayall-idl computer - remember, it is in degrees, so you will have to divide the RA by 15. Getting within a degree is close enough, so no need to be super precise.
+. Focus the telescope
+. Ask the telescope operator to point the telescope to a 5th mag star and to center it on the MOSAIC3 focal plane.
+. Wait patiently for 10 deg twilight.
+= [9] Get Ready to Observe - start of night =
+''No on-sky observations are permitted before 10 deg twilight.''
+. At start of night, check telescope pointing and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane).  When taking the image of the bright star, make sure to create an OBJECT script with NGUI (not a TEST, because MOSSTAT will ignore it), zd filter, 1 - 5 sec exposure.  Watch for MOSSTAT to process the image and report the RA, Dec offsets.  If mosstat fails, it could be because (a) the telescope is mis-pointed, (b) the telescope is out of focus (set the focus approx using the formula above and try again). Once you are able to determine offsets,  give these offsets to the OA with **opposite** sign.  That is, if mosstat reads "RA,Dec offsets = -15.34, 18.32", then you need to provide the OA with the offsets of +15,-18 to zero the telescope coordinates. You can take another OBJECT frame if you want to check to make sure the offset went in the right direction.
+. Move to the beginning of the first MzLS tile position.  What position is that, you ask?  One way to find out is to run mosbot.py (see step 5 below), and look for RA, DEC in expose-1.sh in the exec/mosbot/ directory.  Tell these coordinates to the OA to move the telescope. Another way is to look at teh first entry in the ~/obsbot/pass1.json file on the mayall-idl computer - remember, it is in degrees, so you will have to divide the RA by 15. Getting within a degree is close enough, so no need to be super precise.
+. Focus the telescope
  - create a focus script using the NGUI: exposure time 5 or 10 seconds, zd filter, -100 micron focus steps, click Midpoint to *on*, 9 exposures.
  - run the focus script from the /home/observer/exec directory
 …
 **[wiki:MayallZbandLegacy/NotesforObservers/FocusInfo Example of a focus sequence]
 === Observe - all night long! ===
 . From the mzls@mayall-idl window, generate the top-level observing script (tonight.sh) assuming that we have three plan files named pass1.json, etc.
+=== [10] Observe - all night long! ===
+. From the mzls@mayall-idl window, generate the top-level observing script (tonight.sh) assuming that we have three plan files named pass1.json, etc.
 {{{
    cd ~/obsbot
 …
 Note that if you need to escape the script at some point during the night (see below), you will need to CTRL-C to stop mosbot.py and **restart** it when you are ready to start up again.  If you forget this, you will be observing tiles that you already observed earlier in the night.
 . From the observer@mayall-3 xterm window, start taking exposures using the top-level observing script (tonight.sh):
+. From the observer@mayall-3 xterm window, start taking exposures using the top-level observing script (tonight.sh):
 {{{
    cd ~/exec/mosbot
 …
 }}}
 . "copilot" should already be running. If not, start running "copilot" in the mayall-idl VNC window. Copilot keeps a beautiful running plot of observing conditions.  From any mzls@mayall-idl window:
+. "copilot" should already be running. If not, start running "copilot" in the mayall-idl VNC window. Copilot keeps a beautiful running plot of observing conditions.  From any mzls@mayall-idl window:
 {{{
    cd ~/obsbot
 …
 See [wiki:MayallZbandLegacy/NotesforObservers/Copilot]
 . Monitor focus by checking the image quality on each frame. Keep track of the truss temperature variation and use the information to modify  the focus as needed. Note that the focus may not respond quickly to changes in temperature, so monitor the images carefully before adjusting focus.  The Mayall has astigmatism, so one can sometimes tell from the shape of the images which way to move the focus.  To stop and do a focus sequence:
+. Monitor focus by checking the image quality on each frame. Keep track of the truss temperature variation and use the information to modify  the focus as needed. Note that the focus may not respond quickly to changes in temperature, so monitor the images carefully before adjusting focus.  The Mayall has astigmatism, so one can sometimes tell from the shape of the images which way to move the focus.  To stop and do a focus sequence:
 - Create a file to tell obsbot to quit
 {{{