Swope Operation Manual -New

Swope Telescope operation manual

This manual describes how to take direct imaging CCD data on the Las Campanas 40-inch Swope telescope with the 4Kx4K E2V CCD231-84 detector. Last updated: August 15, 2024 (Nidia )

Activate telescope and instrument:

A set of switches and push-buttons has been installed on the upper left corner of the main desk:

• The new TCS runs on a Windows machine whose remote display is shown in puma's right side monitor.
• To activate the telescope rotate the `TCS and Control Enable' key and push the white button labeled 'Consol Power ON'.
• If the TCS window is not open, double click on the TPS icon in the Windows display. This will bring up the TCS GUI and the KeyPad window (see figures below). The TCS GUI has several menus; 'Pointing' and 'Dome' will be the most used.
• Turn on the dome lights from the KeyPad window.
• In the TCS Pointing menu, select 'Cover Position'.
• Go upstairs, raise the platform with the white hand paddle, and remove the telescope cover. The hand paddle power is enabled by the ON/OFF switch on the paddle, which has three functions allowing movement of the platform, the dome and the wind screen. After the cover has been removed, move the platform all the way down and disable the hand paddle power. Go back to the control room downstairs.
• Use the Pointing menu 'Park' command to bring the telescope back to Zenith.
• Use the KeyPad to turn the dome lights off.
  

We recommend taking sky flats at twilight, which provide better correction (to 1% level) than domeflats. However, domeflats are useful for shutter and linearity tests. The 'Flat Position' command in the 'Pointing' menu will set the telescope for domeflats. The quartz lamp is turned on from a box on top of the light-blue rack (do not exceed 935 Volts).

Before opening the telescope:

• Turn on the fans from the switch in the equipment room.
• The wind screen is commanded from the LPLC touch panel. Click on 'Go Local' (the usual status will be 'Remote'). Use the Windscreen menu to lower the screen. Then click on 'Go Remote'. The LPLC touch panel will be moved to the telescope area in the future.                                                             .
  

• The dome is controlled from the TCS 'Dome' menu. Preferably, do not open or close the dome with the telescope pointing to Zenith.
• Telescope and dome tracking are activated from the KeyPad window.
• The pointing model will be automatically loaded.
• If the E-Stop (emergency stop) button is activated or a power failure occurs, the yellow 'E-Stop warning' light will turn on indicating that the 'E-Stop Reset' button needs to be pushed in order to restart telescope and instrument control.

Swope GUI

The SWOPE-CCD application consists of different controls:

1) Science Camera and Filter wheel control

2) Guiders control

3) Telescope control

In addition to these GUIs there are the image viewer (Quick look tool), the dewar status window, the airmass display and the object list window. A password protect mode allows access to the engineering GUIs. A detailed description of the application can be found here: http://instrumentation.obs.carnegiescience.edu/Software/Swope/

The detector is read out through 4 amplifiers producing four independent files called ccdnnnnc1.fits - ccdnnnnc4.fits. The quadrants as seen in the Quick-Look tool are named counterclockwise beginning from the top right quarter of the image (i.e., top right is c1, top left is c2, bottom left is c3 and bottom right is c4).

Science Camera and Filter wheel control

This window controls the CCD camera and the filter wheel. Exposures are started with the Start button. Macros can be started with the Execute button.

Exposure parameters

ExpTime is the exposure time in seconds for the next observation. For this parameter and the ones for Loops and File# the entry window will be highlighted red after the number is typed. The value is not recorded by the program until the user hits Enter. The exposure time can be changed at any time during the exposure. Remember to hit Enter to validate the new value.

Loops: Setting up a loop can be a convenient way to take flat fields and bias, or to make a series of observations in order to split the total exposure into shorter individual ones.

ExpType: The exposure type (saved in the fits header) can be set to "Object", "Focus", "Bias", "Dark", or "Flat". Selecting "Bias" will automaticaly set the exposure time to 0 seconds. Selecting "Dark" will disable the shutter for the exposure. Selecting "Focus" will enable a focus sequence, automatically setting the loop number to 7 (this can be changed if desired). The focus frame will be saved under a normal filename (e.g. ccd0065.fits). In this frame, the spacing between the first and second images will be larger than for the rest of the sequence, allowing identification of the sequence order.

Binning can be set to 1, 2, 3 or 4 in rows and columns. Note that the readout time given in this manual is for 1 x 1 binning.

Filter: There is room for 10 different filters in the filter wheel. Clicking on the button will present you with the available filters. A 'combo' option is also available to allow combination of two filters.

One or more Quadrants can be selected to be read instead of the whole detector (note that this will not save time because each quadrant is read independently). The selection is enabled by clicking the Q checkboxes

Object: Enter here the title you want for the image.

File: File number will be automatically incremented for every new exposure.

Execute: This command is used to start a macro. The macro file name must be specified on the next window to the right. This option is useful when shutter time and/or linearity tests are performed. More details here:http://instrumentation.obs.carnegiescience.edu/Software/Swope/swopegui.html

Speed: only the Turbo readout speed is available at the present time.

Shutter: This is a flag that indicates whether the shutter is open or closed.

Snap will make a 4x4 binned image of the current field without incrementing the file number. The exposure time is as selected in ExpTime.

Subraster Allows to select subrasters on the chip. The regions can be defined giving its central coordinates followed by the width and height of the subraster (XYWH) or by its corners (XXYY). Savemode minimal will save only the selected region while savemode full will keep the original dimension of the quadrant filling with zero the region outside the selected.

Pointing

• A list of pointing stars is available on puma and mula computers. Under 'object lists', select 'cset.objects' and pick up a star which is close to Zenith.
• On the TCS Pointing menu click on 'Select object' to open the 'Select the telescope target' window:

• Click on the bullet next to 'Simbad' and write the star's name in the window next to it (e.g. HR5212, or hr5212), then click on Search. The object's details will be displayed. Click 'OK'.
• Alternatively, you can click the bullet next to 'Coordinates' and manually enter RA and DEC (e.g. 13 52 00.90 -31 37 10.0).
• In the KeyPad, click on 'Go to target'. The message 'Telescope slewing' will appear in red in the TCS GUI. This message will disappear once the target position is reached.
• Take a short exposure (1-2 s) of the field and compute the required offsets to place the bright star at the center of the image (scale is 0.435 "/pixel). Use the Telescope GUI to apply these offsets. Take a new exposure and repeat procedure until pointing is right.
• In the TCS Pointing menu select CSET. If you make a mistake, you can revert to the previous CSET using the 'Reset CSET' option.
• Next click on Centerfield on the guider window and check that the bright star ends near the center of the guider display. If it doesn’t, move the guider to place it near the center and then click on SetCenter on the guider window; a dialog-box will ask you for confirmation. Do not forget to click  'Park' on the guider window after this, to take the guider probe away from the Centerfield.

Focus

Focus sequences are allowed by setting Focus as ExpType on the CCD command window. This will allow 7 position sequences (Loops =7). This default can be changed to other number if desired. We recommend taking 10s exposures changing focus by 0.050 units in between. The secondary mirror is moved from  the  Focus  section  at the bottom of the telescope GUI (Figure 6). The focus needs to be determined for each filter to be used; a focus value of 23.125 was found for V filter after November 2023 engineering (for that setting, the guider focus was 3700). Focus offsets for the different filters are displayed in the board (a value -0.450 relative to V is good for all the Sloan filters). Once the focus sequence is over the corresponding file can be displayed and examined in the IRAF window. The spacing between focus exposures will be double between the first and second steps to allow identification of the sequence order. Once the approximate focus value is known, it is possible to run new focus sequences using smaller focus steps (such as 0.025 or 0.020). Focus may change along the night depending on temperature and telescope position. Sometimes a new focus sequence will be needed.

If you are using several filters, and  already know the focus offsets between them, you may edit the Filter Hardhat (available under the Camera menu) to set the corresponding offsets so the guider will focus automatically each time you switch filters.  The filter Hardhat also provides a 'Combo' option which allows superposition of two different filters (one from each filter wheel).

If the focus becomes unresponsive, follow the instructions in the picture below (do not restart the Swope GUI):

Guiding

The main components of the guiding interface are the Skymap, Guider1 and Guider2 windows.

Skymap displays a star catalog and and overlay of the science camera field of view (red box) the patrol area of the guiders (blue boxes) and the area where the guiders vignette the science array (dashed rectangle). By selecting a star the catalog entry will be displayed in the text box in the lower left of the window. The selection will also update the probe relative position on the Guider window. The probe will be moved to that position by pressing the Goto button. The guider probe can be also moved by selecting an offset or by using the keypad (after selecting Enabled in the box next to it). The last section of the Guider window allows to select imaging mode (i.e. the guiding mode) or Shack-Hartman (not yet implemented). The focus of the guiding camera can be changed using the text box in the last row or by moving the slider.

The star catalog in use by Skymap is indicated in the top left box; which can be clicked to see the available options and eventually switch catalogs.

Please note that the Skymap display will only be updated to the current telescope position by taking an image (which can be a snap) or clicking the 'Get' button in the Telescope GUI.

Once the probe is at the desired position it should be possible the see the guiding star to appear on one of the guider displays (see figure).

The guider focus can be adjusted by clicking and moving the slide bar button on the guider GUI or just writing the desired focus value next to it. Each time the telescope focus is modified (e.g. to apply focus offsets between filters) the guider foucs has to be modified accordingly.

The keyboard below the guider display is used to interact with the guider computer.

At the beginning of the night a software reset of the camera is recommended by typing DSPI. It is also recommended to check that the PA and PX parameters are set according the values in Table 4. The cooling system is initiated by entering TEC 1.5. To adjust the range of intensities between black and white displayed the command SPAN is used (e.g. SPAN 1000). In order to guide, the guiding box has to be moved on the star image using the cursors. To change cursor steps use the keys INSERT and DELETE.

Guiding is started with <F3> and it is stopped with <F1>. Usual guider settings are 'sn' = 0.5, 'bx' between 19 and 23, 'tf' = 2, 'tg' = 0.60, 'avf' = 0, 'avg' = 1 or 2. Span around 1000 will work for a 10th mag. guide star; depending on seeing and transparency.

A more detailed description of the guider software (GCAM) can be found at this address: https://www.lco.cl/wp-content/uploads/telescopes/magellan/gcam-usermanual.pdf

CHECK LISTS

Beginning of the night:

• Turn on telescope/instrument power and TCS (rotate 'TCS and Console Enable' key).
• Push the white 'Console Power ON' button.
• Move the telescope to the Cover position and remove the telescope cover.
• Lower wind screen from the LPLC touch panel (remember you have to select 'GO LOCAL' to do this and then 'GO REMOTE' again.
•  Open dome shutter (use the TCS Dome menu).
• Turn on the fans in the equipment room.
• Make sure that dome lights are off (check the KeyPad window).
• In the TCS KeyPad turn on Tracking and Dome tracking.
• Turn on guider cooling (TEC 1.5).
  

End of night:

• Make sure the guider is 'off' (F1) and set it to the Park position.
• On the guider console type Tec 0.0 to stop cooling and SPAN 9999999 (or any large number).
• Deselect Tracking in the KeyPad window.
• Close the dome shutter using the TCS Dome menu.
• Move the telescope to the Cover position.
• Turn the dome lights on.
• Go upstairs and put the telescope cover on. Take the platform all the way down.
• Turn off the dome lights.
• In the LPLC touch panel select 'GO LOCAL', set the wind screen to its top position, and select 'GO REMOTE' again.
• In the TCS Pointing menu select Park. This will move the telescope to Zenith and the dome to the South.
• Deselect 'Dome tracking' in the KeyPad window.
• Turn the fans off in the equipment room.
• Push the white 'Consol Power ON' button to turn power OFF.
• Turn off the telescope and TCS by rotating the 'TCS and Console Enable' key.
• Activate screen saver in the LPLC panel.
• Fill out the C40 daily report at https://reports.lco.cl (VPN required).

Appendix

Macros

Macros can be used by placing a text file in the DATA directory of the observer’s account on puma.

The file could be something like this:

filter g

exptime 12

start

filter B

exptime 30

start

filter u

exptime 100

start

To run the macro, the file name has to be specified in the window (usually empty) next to Execute on the CCD GUI, for example: /Users/obs1/DATA/macro_test Then the macro is started by clicking on the Execute button.

Tables

Dome reset

If the dome becomes fully non- responsive (which happens very seldom), it may need a reset from the dome control box located in the equipment room:

Object lists

Object lists can be loaded in the TPS directory of the Windows machine (use a pendrive or connect from puma via SAMBA -ask the technicians).

At present object lists need to be in the following format (this may be changed in the future):

%Object_name%RA(degrees and fraction)%DEC(degrees and fraction), no spaces.

Example:

Filename 'targets.dat'

%JGEM24a%122.215846%-17.516465
%AT2024hfx%124.923208%-17.4687389
%AT2024hfq%126.286902%-24.729418
%AT2024hfs%127.160212%-20.383216
%AT2024hfr%130.266165%-18.593131

In the TPS directory of the Windows machine, edit the file List.dat and add as a new line the filename of the object list you want to load. Both List.dat and targets.dat are in the TPS directory.
Then close the TCS and open it again so the new list can be read by the system.

In the Pointing menu, go to 'Select target' and click on the bullet next to 'Custom object'. The available target lists will be displayed (List.dat file). Choose the list you want to load and click on the next window to select the target. The target details will be displayed. Click OK and then Go to Target.

Pointing Limits

Current pointing limits at Swope are:

Altitude: 20 degrees (airmass 2.9).
Hour Angle East: -6 h
Hour Angle West: +7 h

Checking guider and telescope connection

If at some point you need to verify that the guider has connection with the TCS, follow these instructions:

• Open an SSH connection to the TCS by opening a `New terminal console' with the program 'Bitvise SSH Client' on the Windows PC (login with the usual puma/mula credentials).
• In the new terminal console type: tmux attach, and then enter.
• This will show the TCS window.
• You will see in the terminal messages with the following format: Guider Xnn Ynn Gnnnn (where 'n' is a number). This indicates that the TCS is communicated with the guider.