SPUPNIC

SpUpNIC User Manual

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Introduction

Here we provide a preliminary, and hopefully temporary, user manual for SpUpNIC (Spectrograph Upgrade: Newly Improved Cassegrain) - the recently upgraded spectrograph at the 1.9-m telescope's Cassegrain focus. We plan to produce instructive video clips and a more comprehensively illustrated wiki in future, but for now this will have to do!

The spectrograph's collimator and camera optics have been replaced, the instrument has a new detector, all of the mechanisms are now under PLC control and the software (both for instrument control + quick-look data reduction) has been completely re-written.

The instrument has two sub-systems, the PLC sub-system (controlling all the things that move) and the detector sub-system (controlling the data acquisition process). The drivers for these sub-systems run as stand-alone processes, and the user interface runs as a separate process on top of these. Typically, users will connect to the graphical user interface, although certain diagnostic functions can only be accessed using the command line interfaces.

We hope that you will enjoy using SpUpNIC and that you will provide the instrument team with feedback based on your experience by emailing lisa(at)saao.ac.za.

Quick Start

This is a basic overview of taking data; if you're unsure about anything, the Advanced User Guide section contains more information.

• If the instrument control and quick-look interfaces are not running, they may be started from the panel on the left edge of the screen. The instrument control GUI is started with the absorption spectrum icon, and the quick-look GUI from the emission spectrum icon.
• Ensure that the grating you require is inserted, and then set the grating to the required angle.
• Run a Hartmann routine (see the Advanced User Guide) to establish the best focus for the spectrograph.
• Set the required focus.
• Set the slit width.
• Select the required filter (or leave the filter open).
• Select the exposure type (ARC, BIAS, SCIENCE, FLAT, TEST)
• If appropriate, set the exposure time and number of exposures.
• Select a target from the target catalogue so that the object name and coordinates will go into the fits header.
• If taking a science image, acquire the target, and ensure that it is visible through the slit.
• If taking an arc, ensure that the arc mirror is in-beam, and the chosen arc lamp is on (remember to turn off the arc lamp and move the arc mirror out of beam when done).
• Start the exposure with the Expose button.
• The countdown timer will show the time remaining, and the progress bar will first show the exposure completion state, and then the readout state.

Advanced Users Guide

• The SpUpNIC Control interface has a number of tabs:
  • The Main View tab, in which you'll spend most of your time.
  • The Advanced tab, which may be used if things go wrong.
  • The Engineering View tab, which displays various diagnostic settings.
  • The Config tab, which you should not need for the most part.

• The panel on the right is an interactive schematic of the instrument. Components with in/out or on/off states can be toggled by clicking on the relevant part of the image. The light path is shown in red so that one can easily verify the instrument configuration.

SpUpNIC User Interfaces

SpUpNIC's control displays are labelled "Monitor 1" and "Monitor 2", and are located to the right of the TCS monitor in the warm room. To launch the SpUpNIC Control GUI, click on the absorption spectrum icon in the menu bar on the left-hand-side of Monitor 1. All of the spectrograph sub-systems (e.g. grating angle, slit width, arcs, exposures, guide mirror) are controlled from this GUI.

There is an accompanying SpUpNIC Quick Look GUI, which displays each spectrum after readout. To launch the SpUpNIC Quick Look, click on the emission line icon below the absorption spectrum icon.

The instrument Schematic

Normal operations are performed in the "Main View" tab of the SpUpNIC Control interface. On the right-hand-side is a graphical representation of the instrument, which shows the light path through the various components controlled by the GUI. You can click on the guide mirror, arc mirror, rear-of-slit mirror and Hartmann shutters to move them in and out of the beam, and on the arc lamps and slit illumination to switch them on and off. A blue border surrounding the graphic indicates that the spectrograph is configured for acquisition or calibration, i.e. some component is in the beam that would obstruct its path to the science detector. If the system is correctly set up for a science exposure, there will be no coloured frame and the red light-path will go through to the detector.

Start of run

Setting name and run number

In the SpUpNIC Control GUI:

• At the start of your run, click on the "Advanced" tab. In the "Observer Info" box, enter your name and run number. You can determine your run number from the triplicate "CCD and Unit Spectrograph" log book, stored in the "Log Books" section of the bookcase, on top of the chest of drawers beside the door to the observing floor (behind you, if you're sitting at the SpUpNIC interface). Your run number will be one greater than the previous observer's run number, listed in the log book.

Setting up the Grating

Grating	Order	Blaze (A)	Res (A)	Range (A)	Star Filter	Arc Lamp	Arc Filter
4	1	4600	1	800	None	CuAr	None
5	1	6800	1	800	GG495	CuNe	GG495
5	2	3400	0.5	350	BG39	CuAr	BG39
6	1	4600	2	1600	None	CuAr	None
7	1	4600	5	4200	None	CuAr	BG38
8	1	7800	4	2300	GG495	CuAr	GG495
8	2	3900	2	1150	BG39	CuAr	BG39
9	1	7800	1.5	960	GG495	CuAr	GG495
9	2	3900	0.7	480	BG39	CuAr	BG39
10	1	10000	1	800	GG495	CuAr	GG495
11	1	10000	2	1600	GG495	CuAr	GG495
12	1	10000	5	3200	GG495	CuAr	GG495

• If a grating is mounted in the spectrograph, it will be indicated toward the bottom of the "Instrument Setup" section, e.g. "gr8" in the Grating field indicates that grating 8 is mounted. Below this is the grating angle field. If you need to mount a different grating, rotate the grating to 0 degrees by entering 0 in the "Grating angle" box and pressing "Go". You can also move the grating by entering the number of degrees you wish to move it by in the "Grating angle increment" box below.

• Once you have the correct grating in the spectrograph, you can estimate the desired grating angle by referring to the "grating angle settings" plots in Chapter 9 of the old printed instrument manual. Enter the angle in the "Grating angle" box and click "Go", then compare the resulting arc spectrum with the arc maps in Chapter 10 of the old manual. Automated grating angle determination is on the cards, but has yet to be implemented in the Quick-Look GUI.

• The necessary order blocking filters for your grating setting are listed in the table above. Select the required filter from the dropdown menu below the grating angle control.

Arc lamp and filter selection

• Two arc lamps are permanently mounted in the spectrograph - you no longer need to swap out a lamp - but the arc lamp filters are still changed manually. On the spectrograph, the CuAr lamp is in the vertical housing, with two slots for filters below. The CuNe lamp is below it, housed horizontally, similarly with slots for two filters in the light path. Filter requirements are listed in the table above and the filters are stored in a small, labelled wooden box on the bench in the grating room (North-West corner of the dome).

• The arc lamps are controlled from the "Lamp/Mirror Settings" section of the SpUpNIC Control GUI: Arc 1 is CuNe, Arc 2 is CuAr. Click the appropriate "Change" state button to switch the desired lamp on/off, and to move the arc mirror into the beam to take and arc exposure, and out again when finished. Alternatively, click on the appropriate lamp icon in the instrument schematic - this will switch on the lamp and insert the arc mirror into the beam. Having taken the arc, simply click on the arc mirror icon in the schematic to switch off the lamp and remove the arc mirror.

Focusing the spectrograph

Before each night's observations, you should focus the spectrograph. This is done using a scripted Hartmann sequence, which moves a shutter halfway into the beam, takes an arc exposure; then blocks the other half of the beam and takes a second arc exposure. The arc lines are then cross-correlated to measure the shift between the two. The procedure is repeated at a range of camera focus positions until the line shifts are minimised, indicating best focus. This procedure can be performed manually or automatically. For an auto focus run:

1. Above the grating setup, select slit width 7: 1.05" (or smaller) from the dropdown meny and click "Go".
2. In the "Exposure/CCD info" "Advanced" subtab, select CCD modes "Faint" and "Slow" from the dropdown menus, and CCD Binning "1x2".
3. In the "Exposure/CCD info" "Main" subtab, select "Exposure type" = ARC from the dropdown menu, and enter e.g. 20 seconds in the "Exposure time" box.
4. Move the arc mirror into the beam and switch on the appropriate arc lamp for your grating setup.
5. In the "Instrument Setup" section of the SpUpNIC GUI, select the "Auto" tab.
6. Enter an "initial focus position" (e.g. 3.80), a "focus increment" (0.05 is recommended) and a number of "steps" (try 7 iterations) and click "Run". The GUI will grey out and not be available during the Hartmann focus sequence, but you will see the current "Camera focus" field changing and the Hartmann shutters indicate "Moving".
7. On completion, in the SpUpNIC Quick-Look GUI, in the log box to the left of the spectrum display window, you will see a list of focus positions and their corresponding pixel shifts. Best focus corresponds to a shift of zero.
8. Enter the best focus into the "requested" Camera focus box on SpUpNIC Control's "Instrument Setup" window and click "Go".
9. Switch off the arc lamp and move the arc mirror out of the beam by clicking on the arc mirror in the schematic.
10. The Hartmann test ends with the shutter out of the beam.

Observing Setup

• Target name and coordinates can be entered into the "Target Info" box by selecting the "Load Target Catalogue" option. Navigate to your catalogue via the dropdown File menu in the top left corner of the SpUpNIC window on Monitor 1. The catalogue is a simple text file (e.g. Run002.txt) with the following format:

 Target_1_name HH:MM:SS.S -DD:MM:SS.S J2000
 Target_2_name HH:MM:SS.S -DD:MM:SS.S J2000
 Target_3_name HH:MM:SS.S -DD:MM:SS.S J2000

• Do not include spaces in the target names.
• Use single spaces between the name, RA, Dec and Equinox.
• Select the appropriate target name from the list that appears in the Target Info box after the catalogue file has been loaded.

Focusing the acquisition camera

1. With the guide mirror out of the beam (either set the "Science" state in the "Lamp/Mirror Settings" section of the SpUpNic control GUI -- if it says Guide Mirror "Acquisition", click "Change" -- or click on the guide mirror in the graphical view to allow the beam through the hole in the guide mirror.
2. Turn on the slit illumination (in "Instrument Setup" move the Slit illumination slider to .... and click "Change" to turn on the lamp).

On the TCS:

1. Start exposures with the acquisition camera and tune the exposure time/LUT sliders/slit illumination to allow good contrast of the scratches on the lower slit jaw.
2. Adjust the acquisition camera focus in the bottom right "Camera Focus" box until the scratches on the slit jaw appear as sharp as you can get them.

Recipe for setting up slit position on the TCS - using SpUpNIC Control GUI

The purpose of this step is to figure out where on the acquisition image you need to place your star, in order for it to land pretty close to the ideal spot on the slit. Very bright stars can be seen reflected on the slit jaws, and can be placed on the slit directly, but this is not the case for fainter stars, which need the superior reflectivity of the guide mirror in order to be seen on the acquisition camera.

1. Move the guide mirror into the beam, either by setting the "Acquisition" state in the "Lamp/Mirror Settings" section of the SpUpNic control GUI (if it says Guide Mirror "Science", click "Change"), or by clicking on the guide mirror in the graphical view.
2. Acquire a bright star (e.g. ~4 mag from the Bright Stars chapter of the Sutherland Almanac, available in the warm room), roughly centre it on the acquisition camera and continue exposing.
3. Move the guide mirror out of the beam.
4. Move the rear-of-slit mirror into the beam ("Lamp/Mirror Settings" section, "RoS mirror" change from "Out of beam" to "In beam").
5. Turn on the slit illumination (in "Instrument Setup" move the Slit illumination slider to .... and click "Change" to turn on the lamp). Tune the exposure time/LUT sliders on the TCS until you can clearly see the slit running horizontally across the acquisition image, approximately halfway up.
6. Using the hand paddle, move the telescope to place the star on the slit, approximately one third of the image width away from the right-hand edge.
7. Turn off slit illumination.
8. Open a terminal on Monitor 1, and run the following commands

 * ssh -Y tcs@172.17.1.224
 * password ******* (you should have been supplied with the password)
 * sudo ./1X1_thread_forms
 * password *******

1. .....description of pottercam when functioning sensibly.......
2. An image window for the rear-of-slit camera will pop up. This looks up at the slit from behind, to enable you to check that your star is centred on the slit. Move the telescope such that the star falls on the centre of the slit image in both x and y.
3. Move the rear of slit mirror out of the beam and take a test spectrum (e.g. 20 seconds) of the bright star (in "Exposure/CCD info" pane, select "Exposure type" "Science" from the dropdown menu, enter "20" in "Exposure time" and click "Expose").
4. The resulting image will be displayed on Monitor 2. You are aiming for the spectrum to fall on approximately the central row of pixels. If the spectrum is too high, move the telescope slightly ...east?west?  ; if too low, move the telescope slightly west/east.....? ?
5. When you are happy with the position of spectrum on the image, on the TCS, add a red marker over the position of the star on the slit (TCS "Pointer" pane: "Markers", "Add a red marker").
6. Finally, move the guide mirror into the beam, and add a second red marker at the position of the star. This marker will be used to approximately position stars on the slit that are too faint to be seen reflected off the slit jaws.

Focusing the telescope

1. Acquire a ..... mag star with the guide mirror in the beam