Observing

• Camera Setup
• Checking telescope pointing
• Focusing the telescope
  • Focus change as function of temperature and airmass
• Slewing / Field Setup / Goldcam Rotation
  
  
• Guiding
  • Guiding Overview
  • Guide Star Selection
  • Finding Guide Star form Current Position
  • Guider Software Setup
  • Checklist to Start Guiding
  
  
  
• Offsets and Guided Offsets
• Slew and Shutter Limits
• Non Sidereal Tracking
  
  
• Instrument - Direct Imaging
• Instrument - Goldcam
• Instrument - SQIID
• Instrument - Flamingos

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Camera Setup

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Check telescope pointing

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• Select a star near zenith from the Fixed Bright Star cache in the XOE GUI (cache control GUI) - pick a star that is unambiguously bright - 3rd magnitude or brighter.

  In the Fixed Bright Stars cache, you can search using the Search Window button. Input the current LST and a declination of 32 degrees so that you can search overhead. A list will be generated by the search. Select your super bright star by double-clicking on it, that will send it over from the XOE gui to the XTCS gui.

  • Turn down the camera gains so you don't saturate the cameras with your bright star.

  • Press the Go There button in the XTCS gui to send the telescope to the star's corrdinates.

  • If using Goldcam, you should be able to find the star on the slit jaws using the Slit Camera.

  • If using CCD Direct Imaging or Goldcam, move pickoff mirror (using the small Guider GUI) to the "TV" position to view the star using the Acquisition Camera rather than the Slit Camera - here's how:

    In the GUIDER GUI select the tv button. Wait for the text on the tv button to turn green. If after 60 seconds the text still isn't changing try selecting the button again. If this doesn't work try the reset mirror button. Wait for the instr button to turn green then try the tv button again.

  • Turn up the ISIT/Acquisition camera gain knob (Panel A) and be sure it's initialized (little yellow light is on as well as power light).

• Once you've found your star on the camera, tweak the telescope position using the handpaddle, to put the star in the center of the monitor or slit viewer cameras slit viewing area.

• Zero the pointing here - select the Z button on the XTCS GUI.

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Focusing the telescope

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The focus procedures for SQIID and FLAMINGOS are the same as with the direct CCD, except that one must take individual exposures using the instrument control software and increment the focus position manually in between images.

For FLAMINGOS (f/8), we recommend initial focus increments of 200 steps, narrowing to 50 as one approaches the optimum focus. For SQIID, one must use the f/15 secondary handpaddle and the readout on the secondary control rack. Begin with increments of .05 and narrow to .02 as focus is achieved.

Focusing is done by by doing a "focus sequence"; this means selecting a nominal focus value by eye and then adjusting the focus by a small increment and re-evaluating the focus. This process is repeated until best focus is achieved. The specific procedure for doing this with each individual instrument differs slightly.

• Find an SAO star between 8.5 and 9.5 VM.

• If using Goldcam, position the star at the east (top / upper) end of the slit in order to get several spectra on the same frame by charge shifting.

• Run a focus sequence using the observe command. Refer to the instrument start person, and the ICE manual at:
  
  http://www.noao.edu/kpno/manuals/ice/ice.html
  
  

  Once the best focus has been determined it needs to be set using the handpaddle focus controls. The current focus value is shown on the observer's Telescope Status Monitor, and also on PANEL A, on the yellow numbers labeled FOCUS/FLAT FIELD DISPLAY when the CASS. FOCUS button is pressed.

  Approach focus from smaller to larger numbers when setting focus with the hand paddle. This will standardize the focusing method, for any mechanical sloppiness there may be in the mechanism that moves the secondary mirror.

Focus Variation with Airmass and Temperature Changes


Focus at the 2 meter telescope is known to vary with both temperature and airmass. The approximate relationship between temperature and focus can be represented by:
Delta Focus at f/8 = ( Delta Temp ) x ( -75 units ) temp in deg C

Delta Focus at f/15 = ( Delta Temp ) x (0.014 per deg. F)



Note that this relationship will not accurately predict focus changes for very large temperature changes.

At f/8 the approximate relationship between airmass and focus can be represented by:

Delta Focus at f/8 = ( Delta Airmass ) x ( -130 )

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Slewing / Field Setup / Goldcam Rotation

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1. Select object from the object cache in XOE gui:

(a) Select the cache in the XOE gui

(b) Find your object, and double click on it, or press the Send Next button to send it over to the XTCS gui

2. Or, if the object is not in a cache, enter the coordinates manually:

(a) Bring up the NEW NEXT gui from XTCS

(b) Fill in the object's position and press Apply

3. Now - find a guide star for that object, once it's in XTCS:

(a) Press the blue Search GSC button on the XTCS gui

(b) Select a the brightest guide star from the generated list by double click.

(c) Select the Send to XTCS button to associate that guide star coordinate with your object in XTCS. A small star will show up next to your science target object, and flash yellow and green to indicate the association was made.

4. To move to the new filed:

(a) Press the Go There button on the XTCS gui






Goldcam Rotation - rotate goldcam as follows:

(a) Go to zenith.

(b) Turn on low dome lights (PANEL A below FANS)

(c) Wait for telescope to reach Zenith

(d) Move platform underneath telescope

(e) Remove lock bolt if needed (ask an operator if you cannot move the rotator)

(f) Undo the 3 hand knob / rotator clamps (1-2 turns)

(g) Rotate to desired angle using hand wheel, being careful not to strain the instruments main umbilical cable connections.

(h) Re-clamp the 3 rotator knob / clamps on the rotator.

(i) Stow the platform in the east, and down position.

(j) Turn off low Dome Lights

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Guiding

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• Guiding Overview
• Guide Star Selection
• Finding Guide Star form Current Position
• Guider Software Setup
• Checklist to Start Guiding

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Guide Star Selection - Prior to Moving the Telescope

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Prior to moving to your new science field, you need to do a "Guide Star Search" to look for usable guide stars around your field. So just send the coordinates of your new science field over from the XOE gui, to the XTCS gui by double clicking. Then select on the XTCS gui, the blue button that says "GSC Search".


This brings up the GSC Search GUI

This GUI is, as its name implies, is used to search for and select guide stars. Simply select the search catalog button. This will bring up a list of guide stars and automatically select a default guide star which is the star closest to the current guide probe position. Stars with brightness of approximately 11-12 magnitude are suitable. Brighter stars are better. Adjust the Guider Camera gain on the camera as needed.

Once you have a star you like, just double click on it, and that places it in the top of the GUI, then click on "Send to XTCS" in order to associate the star with your science field.

Next, on the XTCS GUI, select "Go There" and the telescope will move to your new science field, and send the guide probe, to the guide star that you selected just off of your field.

The guide star will show up on the "Guider Monitor", after the guide probes have finished moving. Should you not see your guide star, be sure that the guide probe is not still in motion, by checking the Telescope Status Display, and looking at the "collim" value - that will show the probes position and whether or not it is still in motion.

So - you should now have a guide star on the monitor at this point. You can make adjustments to the guide probe position (star position on screen), by moving one of the 4 arrows on the "Guider GUI".

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Selecting a Guide Star from Current Position

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1. Open a New Next GUI from the XTCS GUI.









2. Input the coordinates of the current position as shown on the Tele: line of the Telescope Status Monitor.

3. Select the Apply button.

4. Start the GSC Search GUI from the XTCS GUI.

5. Ensure that the current coordinates are listed in the Target for search section of the GUI.

6. Press the search catalog button.

This will generate a list of available guide stars and their positions. If the text on the search catalog button turns red then the search has timed out and you should press the button again.

7. Select a guide star by clicking on it and then select the Send to XTCS button.

8. Select the Go There button.

The guide probe should move to the position of the selected guide star. The numbers beside the collim: label on the Telescope Status Monitor should change and the guide probe status listed at the end of the line should change to probe and then tracking.

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Guider Software Setup

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To start / stop or restart the Linux TV Guider Software:

On Teal, make sure there is no Linux TV Guider GUI running (check panel at bottom of desktop for "TV Guider"). If there is a gui running, just exit out of it. Then, on teal's desktop, single click on the "Shutdown Guider" icon, wait for the "busy mouse icon" to go away (about 20 seconds). The software is shutting down. Then single click on the "Restart Guider" icon, as shown below, to start or restart the software.




Once the Linux TV Guider software is running, you will see a Guider Monitor that looks like the one below. And a new "Linux TV Guider GUI" (lower image) will come up on Teal as well.

                  



Linux TV Guider Software - setup and control

Now that you have a guide star, and have the Linux TV Guider Software running, here is how to interact with the software to optimize and begin guiding


Setup the Linux TV Guider Software on your star with these three main GUI functions:


• Warp to Star - this sends the white guide box to the brightest star in field.
• Box Size arrows - allow you to adjust box size for different star sizes - adjust to be sure the star is surrounded by some sky.
• Leak Average arrows - allows you to change in the frame per integration average (leak rate).

Turning Guiding on and Off - use the "Guider GUI" "GUIDE" and "OFF" modes.

NOTE: Automatic "guide star tracking". .

When you first move to a new field, having sent the guide probe to a new guide star, the software is automatically in "track" mode - this means that if you make adjustments to the telescope position, in order to set up your field, the guide probe will compensate or "track" by making corrections that are equal to your movements with the telescope. To turn this feature off: in the :Guider GUI" click "OFF" under modes. This should turn the tracking feature off.




If you have wind shake, you may wish to increase the leak rate a bit, if you have a very bright star, you may wish to enlarge the box size, and or turn down the guide camera gain. If you have any questions at all, see the

Dealing with Linux Guider Software Hangs and Freezes




Should the Linux TV Guider Software be displaying a monitor that is not updating, or that is displaying a "thatched pattern" on screen, then the software is hung. Just follow the "Starting, Shutting Down, and Restarting the Linux TV Guider Software" process as per above, and you should see the system come back up fine.

Is the guide camera turned on, properly initialized, with the gain turned up, so that you can see your field? (see the camera section on the main menu)

Is the guide camera's neutral density filter stuck in the way, filtering your star out? If it is stuck, please ask for assistance, a slight tap can unstick it.

Have the guide probes finished moving? Check the Telescope Status Monitor (VDU) (below) for probe motion - look at "collim" value. If the numbers are changing, the probe is still in motion. Wait for it to stop and check for your guide star again.

Is the telescope pointing verified? Can you easily find bright stars?

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Offsets and Guided Offsets

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Slew and Shutter Limits

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                          HA                         DEC
					  
TCS Slew Limit:     -6:00E    6:00 W          -41.0 S     90.0 N
With Flamingos:     see note below:



Special slew limitations exist for Flamingos

From the Flamingos manual link this statement regarding the special slew limits for Flamingos at the 2meter:


"2-m Declination Limit: The instrument will run into the fork of the 2-m telescope when going sufficiently far north. he declination limit for Flamingos use is +70° . There is no hour angle limit, (although the instrument doesn't clear the control room roof by much). Anyone who needs to observe fields north of +70° must propose to use the 4-m telescope."



• Objects with zenith distances less than 82 degrees.
• Lower shutter limit = 62.3 degrees zenith distance. To observe below this limit see the notes below.
  
  If you command the telescope to move and it does not move - it may be because you are asking it to move to a position it can not travel too based on the limits in software (TCS) as above.
  
  
  
  
LOWER SHUTTER CONTROL - A SPECIAL NOTE: Lower shutter operations and limitations.

Do not operate the lower shutter control lever yourself. This must be done my a staff member.

To observe below the lower shutter limit value of 62.3 degrees, you must have the lower shutter raised by a staff member. Repositioning the lower shutter is a potentially dangerous operation, and can only be conducted by a staff member. Call the WIYN or 4meter Telescope Operator, and request that they come over to reposition the shutter for you. Give them ample warning as they may not be able to get away from their telescope's observing program without some delay, to your observing program.

The lower shutter, when attached to the main shutter, will produce vignetting of the telescope at zenith. Again, to change the condition of the lower shutter, call a staff member to come over and conduct the change for you.

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Non Sidereal Tracking

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• Be sure that the normal telescope tracking is on.
• Enter the RA and DEC values.
• Click ON to start tracking at the desired rates.
• Click OFF to turn Drift Rates off.

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Instrument - Direct Imaging

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Wide Field Acquisition Camera:

The Wide Field camera is turned on on the telescope. It is the long light tan camera. At the back of the camera, you will see a small black power switch. Slide the power switch over to turn on camera power. A red led will light.

Use the Wide Field Acquisition camera for acquiring your fields. The use of this camera requires your to move the pick-off mirror into the "TV" position. This is done on teal's desktop by clicking on "TV" in the "Guider GUI".

When the pick-off mirror is in this position, the CCD is then vignetted, until you move the pick-off mirror back out of the light beam, and into the "Instr" position. ("Inst" meaning "instrument" - which is to say that the light is then going through to the, instrument. Rather than being "picked-off" in the "TV" position, and reflected over to the the Wide Field Acquisition Camera.)


Guider Camera:

The guider camera is turned on on the telescope To focus the telescope the observer will take a series of integrations on the same frame at different focus values. The instrumentation start person will go over this with you.

After the telescope is focused, the tv image must be focused by manually moving the wide field tv acquisition camera. If you cannot focus the tv from the platform, then you can find the offset focus value between the tv and the telescope.
Further information on direct imaging can be found in the Manual here:


Direct Imaging Manual for Kitt Peak - http://www.noao.edu/kpno/manuals/dim/dim.html

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Instrument - Goldcam

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Slit Viewing Camera

The Slit Viewer Camera (aka - slit camera) is turned on on the Camera Control Panel - at the operator's console, with the flip of the power switch. The gain needs to be turned all the way down, and the "init" button needs to be pressed once the power is on, and the gain is down, in order to initialize the camera. Be sure to turn the gain down on this and the other cameras in use as well, whenever you do a comparison, or internal flat, as the amount of light that the camera

The Slit Viewer Camera is the normal acquisition camera. This camera looks down on the silvered slit jaws of the instrument. When you see a star on the slit disappear, that's a good indication that your star is "going down the slit" and the light is getting into the instrument.

The goldcam slit viewer camera video gain must be zero before comparison lamp is turned on or damage will be done to the ICCD camera.


Wide Field Acquisition Camera


The Wide Field camera is turned on on the telescope. It is the long light tan camera. At the back of the camera, you will see a small black power switch. Slide the power switch over to turn on camera power. A red led will light. You adjust the camera gain from inside the control room, at the camera control console.

Normally, all field acquisition is done using the Slit Viewer Camera. However, the wide field acquisition camera can be used for a wider view of your field than the Slit Viewing Camera can provide.

To use this camera you need to set the mirror to the "TV" position. Don't forget that this mirror position vignettes the instrument, so when you are finished finding your field, be sure to select the "Thru" position again on for the pick-off mirror. Once you do so, you should be able to see your object of interest on the Slit Camera, and setup the object for the exposure.

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Instrument - SQIID

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Instrument - Flamingos

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"2-m Declination Limit: The instrument will run into the fork of the 2-m telescope when going sufficiently far north. he declination limit for Flamingos use is +70° . There is no hour angle limit, (although the instrument doesn't clear the control room roof by much). Anyone who needs to observe fields north of +70° must propose to use the 4-m telescope."