FAST Observing Primer

Created: 07/22/04 by PB et al.
Updated: 11/27/15 by TG

When you see this  (back arrow) icon, you can click on it to return to this point.

Table Of Contents

Click on the section below that you wish to read:


This primer instructs new or infrequent users of FAST. Many of the features of both the Realtime system and the Unix operating system are not discussed here. There are other online manuals for the operation of the telescope itself. Note that, even if you are not a new user, there may still be significant changes compared to your previous experience. There is only one username you should use to run FAST and the telescope: "observer." We strive to keep this account unchanged for stability. If you do make minor changes please advise us.

 (back arrow) To Table Of Contents

Getting Started

There are 2 monitors on the main desk in the control room. Log in to flwo60 (a Linux computer), using the name observer. Your typing will first appear on the monitor on your right. The password is printed on the monitor. You will see several windows appear, including a blue one called Main Login, a maroon one called Iraf, a clock, and at the bottom the Xfce window manager icon bar. The blue and maroon windows are simple unix xterm windows. You might use the second monitor to qfast your spectra. Under the new Xfce windows manager both screens are combined into one, flwo60:0.

We use a 3-button mouse with several functions. The location of the cursor driven by the mouse brings focus, i.e. directs keyboard characters to the appropriate window. You simply place the mouse cursor (looks like a capital I) on the window you want to work in. Often, if nothing happened after you typed a command, it was because the mouse was not in the right window. A simple action you can achieve is to click with the left button on a window just about anywhere on it, except on the little boxes at top right: that brings it to the foreground. Other actions, such as clicking, dragging to select, and inserting, are standard X. The vertical bar on the left of each window is the scroll bar. At the top margin of each window is a bar; clicking a mouse button there once results in one of these actions:

Caution: clicking the left mouse button twice on the bar shrinks the whole window into the bar; repeating that on the shrunk bar restores the window.

Before starting the rtsystem, make sure the guide system is up and running on the guide PC. The TV camera and gain boxes stay powered on at all times. Keep the TV gain turned down until you are on the sky. See the docs on the new guide tv system for more info. Use gain = 2.1, or try blev=30, wlev=130, gain=2.5, 32 frames. Try values of 1 blev=40 wlev=90 gain=2.3 for higher contrast, avg 32 frames. Built-in settings are also available; a likely winner for you is "FAST dark".

Basic commands

To start the FAST system, mouse the cursor over to the Main Login window and type

Four windows will appear:
  1. The fast.err Window (small blue)
  2. The Telshell command Window (blue xterm)
  3. The ntcs (Telescope Control System) Window
  4. The finders (Realtime finder charts!) Window
The fast.err window contains the error debugging output for all processes. It may be useful if problems occur, but you may iconify it for now.

The Telshell window accepts all commands for system control of the CCD, telescope, rotator and guider. It has the basic functions of tcsh (command line editing) as well as custom functions. It also has commands built-in to control the telescope, cal lamps and mirror, rotator position and guider functions, which duplicate many of the TCS functions.

  • The full set of Telshell aliases cannot be changed. A number of additional startup aliases and definitions for the system are in the file /home/observer/.nfast.rtrc, which is executed when you type gofast. If you need more aliases or conditions at startup, edit that file very carefully; avoid replacing anything.
  • Upon startup, you are prompted for the binning (only in the spatial direction) that you desire; the standard setup is binby2. To change binning, the commands are binbyX, with X=1, 2, 3 or 4. For example, in the Telshell window, type binby2, which will result in 1x2 binning. You can also use the progfast command, which will prompt for the bin factor desired.

    The images are stored in a directory named /rdata/fast/YYYY.MMDD, for example /rdata/fast/2006.0917 for 2006 Sept 17th. The directory changes and appears automatically at 12 noon. Data are stored as FITS files (without extensions). There is a local storehouse of data files that reside at /faststore, for example /faststore/2006.0917. Every morning at ~8:30 AM the files from the last nights data directory are copied into the /faststore directory. Data are also transfered after that to storage on disk in Cambridge.

    Two or more Telshell commands may be concatenated in a single line by typing them in succession, separated by a semicolon. Not all commands are suggested for use this way, as some commands like total will return and move to the next command before completion. There are only a few commands you need to know to take and look at an exposure:

    bias n
    Takes n zero-second exposures and names them ``BIAS''.
    total n
    Will do 2 fast clears of the CCD, open the shutter for time n, where n is seconds, reads out the CCD and store the data. No prompt will be made for comments - you must enter a name via "object" otherwise file is named after last object name, or seqno.fits (seqno is a sequence number) if no object name has yet been set. If you loaded your object from a catalog through TCS, it will set the object name as well. Total cannot be used to change the exposure time in the middle of one already in progress. To change an exposure time for an exposure already in progress see the extend and istore commands below.
    extend N
    Add N seconds to the current exposure time.
    Stop the current exposure immediately and store the file.
    godark n
    Same as total except the shutter isn't opened. The exposure is named ``DARK''.
    goflat n
    Takes an exposure of length n, labels it ``FLAT'', and notes in the header that the exposure is a calibration flat field.
    repeat n CCDCOMMAND
    Repeats n times the following CCD command. For example: "repeat 5 flat 7" will acquire 5 7-second exposures labeled FLAT (see above). Notice that there is no feedback on the repetitions in the Telshell window, although ntcs will show information about each exposure as usual.
    Prompts for a title and an exposure time (in seconds). Performs a fast clear of the CCD, opens the shutter, reads out the CCD and stores the data. Information contained in the comment block is automatically store in the data header.
    Stops the current exposure (no readout) or sequence of repeated commands.
    clear [ n ]
    Clear charge from the ccd n times
    cc [ n ]
    clears the ccd (fast read) n times.
    Alias for abort
    object name
    Gives the next file a name, puts that name in the FITS keyword OBJECT.
    takes a 5-sec HeNeAr exposure (for binby4); positions mirror and turns HeNeAr lamp on/off.
    takes a 10-sec HeNeAr exposure (for binby2); positions mirror and turns HeNeAr lamp on/off.
    cexv exptime
    takes an exptime-sec HeNeAr exposure; positions mirror and turns HeNeAr lamp on/off.
    view seqno
    displays with ds9 the 2-D fits file numbered seqno in the current data directory.
    Changes to the current data directory and displays the location.
    Invokes the comment editor. The comment block is stored in the fits header as comments.

    Comment Editor

    The comment block can be edited by typing the command comment. Here's how the comment-editing window appears:

    When the window appears, move the cursor to the right side of the window where the changeable parameters are. On the 1.5m, the coordinates, airmass, times are transferred from the mount PC. If you wish to quit and preserve (discard) your edits, click on 'File' ('Quit') when done editing.

    ***NOTE: Please keep the comment fields updated to include correct grating, tilt, and slit for the headers!!!***

    How to observe with FAST

    0.  Before taking any images, from the iraf session enter the initlog
        command to set the Date and Page Number in the logs. This is
        required to ensure proper logs are generated. You can then view
        the log for the current night with the iraf command "viewlog" at
        any time. You can also epar qfast at this time.
    1.  To take FLAT and BIAS exposures for the standard 300-gpm, 3" slit
        combo configuration, in the telshell, type "dobfx2x4-300" which
        is aliased to "source ~/scripts/dobfx2x4-300" and takes 10 (10) BIAS 
        and 21 (10) FLAT exposures with binby2 (binby4) in about 15 minutes.
        To take flats for other setups, turn on incand, move sky/comp to
        comp, and type "repeat 10 flat time".  Remember to turn off the
        incand lamp when done! To take only biases, "bias 10" will yield
        10 BIAS files. Each night, check your calibrations to make sure
        they are normal (see the checklist).
        Here is a binby2 bias (just noise):
        And here is a binby2 15-sec 300gpm flat (in 3 pieces to show more
        dynamic range; from top to bottom, right, middle and left of the CCD):
        If the biases or flats look different to you from the images above, please
        report that to the staff as soon as possible (call in the beginning 
        of the night, send email and describe in the log at the end).
    2a.  Measure the FAST focus once at the beginning of your run with 
         the standard (300 gpm grating) setup. Follow these instructions.  
         A good time to do it is in the afternoon, after darks, biases and
         flats. For the 600 (1200) gpm grating, add 30 (100) focus units (thanks 
         to Warren Brown for the definitive numbers) to the best focus value
         you measured for the 300 gpm grating.
    2b.  For FAST combo observing, make sure that the HeNeAr line at 7384A
         is positioned at pixel 2660. See the printout to the left of the
         whiteboard in the observing room.  To fine-tune the tilt, one
         step of the micrometer (see the FAST description for its location;
         you must be trained in its use) moves the line by ~9 pixels.
         Increase the micrometer reading to decrease pixel location.
     3.  Take darks in the afternoon and morning.  Type "dodarkx2"
         and/or "dodarkx4" in the Telshell for 5 binby2 and 5 binby4 
         900-sec DARK exposures (so each script takes about 75 minutes to
         run. Good times are in the afternoon (assuming the chamber is not 
         in use) or in the morning after observations. Use cntrl-C to exit 
         a script.
     4.  Before sunset and once the darks are finished, fill the dewar and
         record the fill in the log that is usually on the side of FAST or
         in the control room in a conspicuous place. You can display,
         which contains the night's log with "ghostview" (usually aliased
         as gv -orientation=seascape), after you cd to the night's directory. 
     5.  At sunset open the dome.  Go into the chamber and press the
         "Open" button twice.  This button is to your left as you enter.
     6.  Open the mirror covers.  This is the knob to the left of the
         south pier.  You turn to "open" and release.  The first 4 mirror
         covers open; about 10 seconds later the other 4 do.  Make sure
         they are all open.  If not, try "open" again.  Remember to wait
         about 10 seconds to see if anything happens.  If not, close and
         then reopen.  If this relay box gets confused, wait 5 full
         minutes and try again.
     7.  Start up IRAF with "ecl" or "cl" if you prefer; cd to qfast.
         epar qfast and change the "Observation date", and leave with
         ":q". Qfast lives in the "procd" package "initlog" that includes
         the logging scripts and is loaded automatically. Note that 2
         options are available for the qfast parameter "Calibration file
         name," depending on whether you are using the [300 gpm/600 tilt]
         grating or the [600 gpm/440 tilt] grating, respectively,
         "comp300+600" or "comp600+440."
     8.  Leave the rack and the TV gain down until you are ready to
         observe an object.  You can verify the focus of the spectrograph
         in the meantime.  Do an "splot" on the "COMP" exposure you just
         took.  Zoom ("a" and "a") in on the range near 2000 pixels.  Mark
         the beginning and end of the Gaussian-looking line profiles with
         "k"; you want the FWHM to be below 4.1.  If it's not, try again
         these instructions and note any
         change in the logs. You may want to adjust the Guide Rates of the
         handpaddle from the "Rates" menu in the yellow window; I find a
         value of 3 for both RA and dec to be fine (default is 0.5, which
         is very slow).
     9.  Turn on the rack as follows: MAKE SURE the "RA" and "Dec"
         indicators on the TCS-PC (right monitor) are solid blue and not
         flashing red.  If they are, then either hit the hot key on the
         mount (to the right) PC keyboard (F9) (it is marked in red) or
         click on "Stop" in the ntcs (yellow) window.  Then go into the
         back room and push button "2" on the rack.  Wait about 5 sec for
         the relay to click.  Then flip switches "3" and "4" in that
    10.  Turn on the telescope and dome tracking in the tcs window and
          observe a velocity standard, such as NGC 7331; move the mirror
          to "Sky".  In the CCD window type "comment" and make the
          appropriate changes.  Then say "repeat 2 total 180"; this gives
          you two 3-minute exposures.  Guide the telescope by hand during
          these exposures.  Do a "cex" afterwards.
    11.  Find a star (not too bright) near the center of the guider field
         of view. Press either button on the box labeled FOCUS (separate from
         the handpaddle). You may need to go past a good focus (as compact a
         star as possible) and return to obtain the optimal focus. The focus
         system has a low and a high speed, controlled by a toggle switch near
         the 2 buttons.  The red LED readout next to the guider monitor shows
         the position of the secondary relative to the primary; the numbers
         increase as the secondary moves closer to the primary.
    12.  If the dome gets lost: from the ntcs window, open tele tasks and
          click on Dome Init. Then turn dome track back on.
    13.  Do some of the smaller projects -- AGN monitoring, stars, etc.
         Often they have specific standards they want for comparison, like
         Massey standards, which should be indicated nearby.  Generally
         you want the standard for a given object to be near the object
         itself in the sky.  Also they will often want multiple exposures
         (usually short -- a few minutes tops) of both the targets and the
         standards.  Remember to do a "cex" (TV gain down!) after each new
         object (not each new exposure of the same object).
    14.  Observe! Normally, projects provide online 
          catalogs of all objects. These minimize errors and speed up operations.
    15a. NOTE: check the observing instructions for each project to
         see if you need to rotate to the parallactic angle. Note further
         that to rotate, it is essential to be at or near the zenith!
         NOTE: If you enter coordinates that are inaccessible, the
         "Next" indicator on the right PC monitor will be red and the
         telescope will not slew.  So do some other object.
    15b. To check an exposure for redshift, say "qf 161" (for instance) in
         the red IRAF window, in the "qfast" directory there (see Appendix
         1).  To get a redshift (instead of just a spectrum), say
         "quickred=yes".  Type 'q' in the non-Tek IRAF window to achieve
         the quick-reduction.
    16.  To stow the telescope and dome, click on "Stow All" in the ntcs 
         window; the tracking is also turned off by this action.
    17.  Close the mirror covers -- check visually that they all shut.
    18.  Close the dome and restart the A/C; leave fan on 'Auto'.
    19.  Turn off the rack in the order: switch 4, switch 3, button 2.
    20.  Source the standard bias+flat script again at the end of the night:  
         type "dobfx2x4-300"
    21.  Make the night's entry in the on-line observing report.
    22.  Fill the dewar and record the fill in the log.
                                        APPENDIX 1
    A. Windows on flwo60 --there are 5. 1. IRAF window 2. Telshell window. Do "total 600", "comment", "dirs", "dlink", "cex" and so on from here. 3. NTCS window -- yellow. This is where you control the comp mirror, the lamps, enter new coordinates, slew or stow the telescope, and so on. 4. Fast.err -- small, white. Tells you what's going on. You do nothing with it other than look at it to 5. Finders -- this is a version of ds9 with another name. As you process new coordinates with tcs, a finder chart will automatically be retrieved from dsseso. If you mistakenly exit this window it can be restarted with the command "dofinders". Once in a great while the eso server may not be available, due to network or other problem. This can cause the RT system to hang awaiting a chart. In that case, exit the finders window. Then run finders_dssstsci, which will open a window connected to stsci. Then run dofinders and finders will then fetch new charts from the Stsci servers. If eso comes back later you can exit the finders window, and run finders_dsseso and switch back. Another dofinders and charts will be coming from Eso. In the case of a network problem exit the finders window and use the printed charts! B. You can use vncviewer to see what the CCD is doing, for instance. Use the command vncviewer ccd60:2. The password is the same as the flwo60 observer account. If there is a problem, you may be asked to report its contents. C. If something goes awry: 1. To interrupt an exposure, in the CCD window say abort 2. To get rid of a file use the rm command, again in the CCD window. 3. If you did a bad repeat command, to stop that say "abort". D. Getting the headers right. 1. You enter the new coordinates from the ntcs (yellow) window. - from a catalog: load the catalog by saying "newcat whatever.mct"; it knows in which directory to look. Select an item by its sequence in the catalog with "#23", or by name with "!M31" or "!awm7_2.002". - by hand -- type in the RA and Dec and epoch with fields separated by spaces; remember to update the object using the object command. 2. If the next target came from a catalog, you're set. Just say "total 300" in the CCD window. 3. If you are entering coordinates by hand, you have to update using object as well. Always do this before you start the exposure, Then you can say "total 300" to start exposing. E. IRAF directories and qfast There is a "/home/observer/qfast" directory where you may use "qfast" (or just "qf"). That helps, because qfast generates a lot of ancillary files that you don't want in your data directory (e.g., /fast/2010.1003). Toggle between the "qfast" and "[date]" directories with "back". You need to be in the data directory to do splots. Use "view" (Ds9 of the whole chip) from the CCD window. The various programs (view, q, splot) differ in terms of what argument they take. "qfast" and "view" require only the number of the exposure (i.e. "qfast 67") whereas "splot" needs the full file name (if you use ecl, type the number, e.g., 0035, and then a tab will fill in the rest). There are valid wavelength solutions (300 and 600 gpm) already created for FAST quicklook (qfast). The key to making this work is to make sure the following files are in place, and that they are referenced properly from qfast, and that you operate qfast only from the directory where you have the files (the trash directory). The example below is for the observer account, the one to use unless you are Perry or Mike. You may also create your own wavelength solution; notes on doing that and a HeNeAr atlas are in the blue FAST notebook by the stereo. epar qfast in IRAF to look like the following (binby4 in this case): PACKAGE = procdata TASK = qfast nobs = 61 FAST image number to process (rootdir= /fast/) Spectrum image root directory (obsdate= 2010.1004) Date of observation directory (yyyy.mmdd) (fcal = comp300+600) Calibration file name (caldir = /home/observer/qfast) Calibration image directory (row1 = 10) First row for spectrum search (row2 = 70) Last row for spectrum search (keepnam= yes) Keep object name in file name (y or n) (apdisp = yes) Display aperture and background (y or n (imdisp = no) Display raw image (y or n) (spdisp = yes) Display spectrum (y or n) (quickre= no) Find redshift (y or n)? (delquic= yes) Delete quick-look 1-D spectrum (y or n)? (verbose= no) Log progress (y or n)? (flpar = no) flush pfile on assign? (mode = ql) Run qfast only from the /home/observer/qfast directory (essential!). Make sure the following files are in place: /home/observer/qfast/ /home/observer/qfast/database/ Extra copies of all of these files are stored in the /home/falco/qfast directory. Note that qfast creates extra ap* files in the /home/observer/qfast/database/ directory as the night goes on, you may ignore or delete these. qfast problems: If "q" is ambiguous, type "procd" If qfast says id* file not found in the trash directory, you are probably not running qfast from /home/observer/qfast. pr> q 130 row2=150 QFAST: Calibration file not in /home/observer/qfast pr> pwd /home/observer pr> cd qfast pr> q 130 row2=150 [] refspec1='' pr> q 46 ERROR on line 202: ambiguous task `refspec' qfast (nobs=46) try exiting iraf, cd to home, and re-start iraf with ecl, then cd to qfast ** To get quick redshifts, say quickred+, or epar qfast and turn on quickred. Then epar xcsao, and make it look for the template directories in /home/perry/template . Look there to see what the template names are, and then when it asks you which ones to use, you can tell it. F. It is possible to the change the integration time on the fly. If you want to extend the exposure longer, use the extend [n] command to add n more seconds to the current exposure. If you wish to stop a current exposure use the istore command to stop it now and store the integration. Or if you wish to stop and discard it just use the abort commad. G. It is possible to update the telescope coordinates if it is consistently off. Move it by hand to where it should have gone, then on the right PC keyboard, say "Alt =", then "y". I. How far to drive the telescope? To the West: HA of 3.5 hours; up to 4 if dec is around 30. East: HA of 3 hours


  • If you see no stars on the guide TV, make sure the mirror is in the SKY position.

  • If you integrate for a while (ideally, not very long) and expect to see a spectrum but you see nothing, make sure the grating cover is open.

  • If the FAST CCD stops reading out or the status displayed in tcs does not change, see this link: CCD60

  • Sometimes tcs freezes; everything else seems alive, but tcs won't work. A likely explanation is that there is a sub-window (like TeleTasks) hidden but still active. Try hitting the "front" key a few times or iconifying the main tcs window to make sure there isn't one of these hanging around.

    If your command window is still responsive, type "exit" there. When all the tcs-related windows have vanished, type "gofast". If it will not respond you can try killing this window using the X at the top. Let system go away then retry gofast.

    If none of the above works, it's probably necessary to reboot flwo60 and start over. If you do that, you might as well go through the whole telescope startup routine again.

    If you get into bad trouble, for example the screen locks up on you and you get no response for several minutes, you will have to reboot the system. You may also have to do this to restart after being shutdown because of maintenance work or power problems.

    1. If you can still type commands into some window somewhere ( on flwo60!)
    2. Try and exit the Realtime system. Then use the Xfce large K button at the bottom left of the screen. Select Logout at the bottom. This will bring up a menu with several choices. Usually select the "Restart Computer" button here to reboot.
    Within a few minutes, after a lot of messages, the login window should be back. You can log back in, and then restart system with gofast.

                                        APPENDIX 2

    Created: Susan Tokarz 08/20/01
    Updated: Nathalie Martimbeau 04/05/06
    Updated: 10/03/10 by EF

    The following protocols have been established for taking data using the FAST spectrograph. Their purpose is to make automatic reduction possible while maximizing the quality of the spectra.

    The standard set-up is:

    300 gpm grating
    3" slit
    binby2 (binby4 may also be used)
    Unless otherwise indicated, this setup is assumed for the exposure times we mention below.

    The standard method to enter object names and coordinates into the telescope control system for ALL observations is through a catalog. If there is a request for Director's Discretionary Time, please add the observation to catalog prog099.mct, for program 99, and use this catalog. The catalog method ensures that correct program numbers and PI names are inserted in all image headers, which is essential for our pipeline processing.

    1. Take 5 binby2 DARK exposures at the beginning and end of each night. If you run out of time at the beginning of a night, remember to do it at the end of that night. DARKs are critical to obtain the highest quality of reductions. It is strongly preferred that you use a script: 'source /home/observer/scripts/dodarksbinby2' from Telshell. This script will run for about 1.2 hours. On any given night, if you plan to observe for a program that uses binby4, you will also need to take 5 binby4 DARKs. Please use the script: 'source /home/observer/scripts/dodark2.5', which will take 5 binby2 and 5 binby4 DARKs and will run for 2.5 hours. If you are unable to observe or you think you really need more darks, 'source /home/observer/scripts/dodark5' will take 5 hours, twice the number of binby2 DARKs, and the same number of binby4 DARKs. Although the scripts are strongly preferred, you may also collect DARK exposures manually; see the FAST primer for details on the godark command.
    2. Take BIAS and FLAT exposures at the beginning and end of the night with the standard BIAS and FLAT script 'doflats.' Invoke it with 'source /home/observer/scripts/doflats', which will run for about 15 minutes. It will take 10 binby4 BIAS, 10 binby4 4-sec FLAT, 10 binby2 BIAS and 15 binby2 7-sec FLAT exposures. The script is preferred, but you may do all this manually; however, you'll need to turn on the bright incandescent lamp manually and also remember to turn it off when done (all of this is automatic with the script). See the FAST primer for details on the bias or goflat commands.
    3. To summarize, the required numbers of calibrations for the standard setup are:
              FLATS   BIASES  DARKS
      binby2   15       10      5
      binby4   10       10      5 (if needed)
    4. FLATs are essential to calibrate the illumination of the CCD. If you change the grating/tilt during the night, take 10 FLAT exposures after you change the grating/tilt but before you observe any objects. If you will finish the night with the new grating/tilt, you may leave the flats until the end. The point is never to forget to take appropriate flats.
    5. Take 5 sky exposures in the standard setup at the beginning or end of the night. You should only try skies once you have developed observing expertise. Make sure that the guide camera gain is turned down all the way! For consistency, always name the sky observations "sky" and no other name. When taking sky exposures, it is a good idea to look at the 2-d image to check that there is no stellar spectrum in the exposure. Exposure times for sky exposures should be short, on the order of 2 to 10 seconds. Please remember to take a comparison after you have finished your sky exposures. These exposures are wavelength-calibrated and extracted to 1-d spectra, which requires a comparison. Sky exposures are Program '#57 Velocity Standards' and the P.I. is 'All'.
    6. Check your personal email and the 'observer' email for instructions on what to observe. Perry Berlind or Mike Calkins should either email or call you with recommended observations. Also, check the link What to observe tonight. Check the observing binders on the shelf above the computer monitors in the control room for program-specific instructions.
    7. Comparisons should be taken after each new object RA and Dec. For binby2, a 16-sec exposure is needed (type 'cexx'), and for binby4 an 8-sec exposure is needed (type 'cex').
    8. The telescope should NOT be moved to another object during a comparison exposure even in cases where good wavelength solutions aren't especially important. Our automatic reduction system uses an algorithm that matches the telescope RA and DEC of objects and comparisons.
    9. If an object is underexposed, observe it on your second attempt for a sufficient time to get a scientific result; don't expect to add two or more poor spectra to get a reliable velocity. Underexposed spectra add greatly to the difficulty of extraction and require individual, time-consuming attention.

      Doug Mink wrote qfast, an Iraf script that allows you to quickly (and roughly) reduce your spectra for a look at the telescope. It produces a plot of the 1-d wavelength-calibrated spectrum, calculates a velocity and marks the absorption and emission lines for that velocity. Note that there are wavelength-calibration files for the 300 gpm/600 tilt ( and 600 gpm/440 tilt ( gratings. Thus, you should be able to determine whether you have a sufficiently high SNR for a reliable velocity measurement. Although the R value can be used as a rough guide (the higher, the better), you should be able to see for yourself that, e.g., the Mg and Na lines are believable and that emission lines, if present, are clearly real and not noise spikes or cosmic rays.

    10. Standards
      • Once a month, observe a throughput monitoring object, a white dwarf, such as HZ44, from the list of photometric standards using a 5" slit to gather as much light as possible in the slit.
      • Nightly observe a photometric standard, one blue and one red.  If possible and if the standard is not being observed in conjunction with AGN, SN, or QSO monitoring, it should be observed at an airmass no greater than 1.1.
      • Observe a velocity template or velocity standard once a night. Usually you can do it while still in twilight.
      The catalog files containing the standards are in the /pool/Realtime/lib/catalogs directory on flwo60: massey.mct (rvstd.mct) for photometric (velocity) standards.

    11. Please note carefully in the fastlog.lis file any slit or grating change and any comments for the observed object that may help identify its spectrum (position on the slit, clouds, etc.). Also please note any additional stars or galaxies that appear on the slit and could be mistaken for the target object. However, if the slit has been rotated, please indicate where the desired target is located in pixel row. WARNING: Avoid editing the fastlog.lis file while an exposure is in progress; if the exposure finishes before you, you will likely damage fastlog.lis. The format of fastlog.lis is fastidious, especially regarding quotation marks; it is easy to damage the file, so be careful!
    12.  (back arrow) To Table Of Contents