What to do in the afternoon

last update:  May 30, 2013

1.  Log on to pixel as mmtobs.  In the IRAF window you are using for data collection, type

cl> ccdinfo

to be sure that the CCD computer is up and talking to pixel.

2.  Bring up Conductor, the MAESTRO Spectrograph control software, if it is not already running.

3.  Make a directory for tonight's data in /home/mmtobs and start a new log.

4.  Check the CCD by taking a bias or two.  It is normal for the CCD to have collected charge in the bottom of the format if the lights have been left on in the chamber, and the CCD hasn't been read out in a while.  It's best to have the lights in the chamber off.

5.  Pick the section of the CCD you will save.  Lately we've used [1:4096,1:2048] when binning 1x1.  This changes slightly every time the dewar is remounted, but it's a good idea to pick one section for the entire run and stick with it.

6.  FOCUS.  After the spectrograph is mounted on the telescope, it is necessary to focus the guide camera and spectrograph.  If someone was using MAESTRO before your first night, you should not need to change the focus, unless there has been a huge change in chamber temperature. 

Here are the steps to focus:

1. Select the slit you want to use for science tonight.
2. Focus the internal guide camera on the edge of the slit hole by moving it on its stage with Conductor.  You may have to turn on a quartz lamp in order to see the slit plate.  Once you are focused, you can deactivate the guider focus frame in Conductor.
   
3. Select the narrowest slit that is available.  Be sure the CCD binning is 1x1.
4. Focus the spectrograph by taking internal Th-Ar exposures at different L1 positions.  
   
• First, zero the position of L1 by running it to the REVERSE limit, and zero-ing the steps.
  
• Take well exposed (150 sec)  Th-Ar exposures.  Take steps of 200 units between exposures for a first pass, then go back and take smaller intervals near the best L1 focus.   
  
• We sometimes have trouble recovering if we hit the L1 forward limit;  try to avoid it.
• Use imexam or your other favorite script to pick the best focus from the focus series you have taken.  Be sure that you go THROUGH focus and pick the L1 position at the "bottom of the parabola". 
  
• There is sometimes a slight tilt in the CCD dewar;   be sure to look at lines in the middle of the format and in the edges, to "split the difference" and pick your best L1 focus.
• Set the L1 stepper to the best focus.  Now you can deactivate the the L1 Focus Actuator frame in Conductor.
5. When you get on the sky, the telescope operator will focus a star on the slit by moving the telescope secondary.
   
6. To really see how good your focus is, and what the spectral resolution is, take an exposure of a "low vsini" star (see the list on the MAESTRO home page). These are stars whose lines have widths << MAESTRO's spectral resolution.  Taking data on one such star per run is more than sufficient for most programs.  This tests the focus all the way through the telescope and spectrograph.
   

7.  Take Calibrations  (see page on Recommended Calibrations)

1.  Take a long Th-Ar through the slit you will use for science
2.  Take a Quartz through the slit you will use for science
3.  Take Milky Flats if they are available. 
4.  Take 5-10 zeros (bias frames) so we can monitor some subtle fixed pattern noise which we are hoping to track down and eliminate.

8.  The telescope operator will arrive at the summit at about 4pm.  Check that he or she has received your observing catalog. 

9.  Turn off the lamps, go have dinner, watch the weather, and relax until sunset.